Poster Abstracts

L. Abbo: Network boundary study in coronal hole and quiet Sun regions with HINODE/EIS data
Abstract Author(s): Abbo, L. (1), Gabriel, A. (2)
Institution(s): (1) INAF-Osservatorio Astronomico di Torino, Pino Torinese (TO), 10025 - Italy, (2) Institut d'Astrophysique Spatiale, Université Paris-Sud 11, 91405 Orsay - France
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 1

Images in spectral lines formed through the transition region show the boundaries of the supergranular cells in enhanced brightness, up to coronal temperatures, at which point the cell visibility disappears. This was interpreted as due to the magnetic field lines, concentrated at the cell boundaries, spreading out at the higher level and lower pressure of the corona, leading to near horizontal fields ('canopy' model, e.g. Gabriel 1976). Theory cannot predict the precise temperature of this spreading, which must depend on observations.
Using observations from EIS spectrometer on Hinode and CDS spectrometer on board SOHO, we analyse intensity maps over a range of temperatures through the upper solar atmosphere, from transition region up to coronal layers. Our purpose is to study the network boundary width of supergranular cells through the analysis of spectral lines formed at different temperatures in order to explore the expansion rate with height of the magnetic funnels. The method consists in analysing the autocorrelation function of monochromatic images over a range of temperatures up to the solar corona. The study concerns coronal hole and quiet Sun regions in order to investigate a possible variation in the temperature and magnetic structure of the flux tubes.

A. Asensio Ramos: Bayesian model comparison in spectropolarimetry
Abstract Author(s): Asensio Ramos, A. (1)
Institution(s): (1) Instituto de Astrofisica de Canarias
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 2

The selection of a model for the inversion of Stokes profiles is typically done based on subjective reasons. In this talk I present the application of Bayesian model comparison techniques for deciding which is the model best suited to the observations. The Bayesian approach correctly balances the complexity of the model with the amount of information present on the observations.

L. Bellot Rubio: Pervasive linear polarization signals in the quiet Sun internetwork
Abstract Author(s): Bellot Rubio, L. (1), Orozco Suarez (2)
Institution(s): (1) Instituto de Astrofisica de Andalucia (CSIC), Granada, Spain; (2) National Astronomical Observatory, Mitaka, Japan
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 3

Using Hinode data, we demonstrate that linear polarization signals occur nearly everywhere in the quiet Sun internetwork. As the noise level is reduced, up to 75% of the area covered by the observationsshow clear Stokes Q or U signals. The mere presence of linear polarization implies that internetwork fields are very inclined, assuggested by other studies. We determine the distributions of field strength, inclination and azimuth by inverting pixels with Stokes Q or U amplitudes of at least 0.58% of the continuum intensity, i.e., 4.5times the noise level. These signals, which account for more than 50% of the field of view, allow a very precise determination of the magnetic field vector to be made. At the highest angular resolution to date, our results confirm that internetwork fields are weak and highly inclined, but not completely horizontal nor isotropicallydistributed. We suggest that these fields are the ones traced by Hanle measurements.

B. Schmieder: Proto-sunspots at the beginning of Solar Cycle 24 observed by THEMIS/MTR and Hinode/SOT
Abstract Author(s): Schmieder, B. (1), Guo, Y. (2), Bommier, V. (1)
Institution(s): (1) Observatoire de Paris, (2) University of Nanjing
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 4

Coordinated campaigns with THEMIS, Hinode and other instruments have allowed us to study the starting of the new solar cycle in 2009. Ephemeral bipolar regions appear at high latitudes. We performed a comparative study between THEMIS/MTR and Hinode/SOT polarimetry analysis using UNNOFIT or MELANIE inversion codes. SOT allows to detect fine vertical bunches of flux tubes. These bunches of flux tubes never achieve to create a sunspot and even a pore. MTR allows us to have magnetic information at different levels in the atmosphere through the flux tubes.

R. Erdelyi: MHD waves in magnetic bright points: The construction of magnetic waveguides using solar magneto-seismology
Abstract Author(s): (1) Erdelyi et al.
Institution(s): (1) SP2RC, University of Sheffield
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 5

Here we demonstrate how the observation of broadband frequency propagating MHD waves in magnetic flux tubes between the photosphere and TR can provide valuable insight into their magnetic field structure. In a case study, by implementing a full nonlinear 3D MHD simulation with realistic photospheric drivers, we demonstrate how the plasma structure of lower atmospheric magnetic flux tubes can act as a spatially dependent waveguide for a range of MHD waves (kink, sausage, Alfven etc.). In particular, for the torsional Alfven waves the frequency filtering of the flux tube is exploited. Importantly, for solar magnetoseismology applications, this frequency filtering is found to be strongly dependent on magnetic field structure. With reference to anobservational case study of propagating torsional Alfven waves using spectroscopic data from the Swedish Solar Telescope (SST), we demonstrate how the observed 2D spatial distribution of maximum power Fourier frequency shows a strong correlation with the presented forward model. This opens the possibility of beginning an era of lower atmospheric (chromospheric) magnetoseismology, to complement the more traditional methods of mapping the magnetic field structure of the solar chromosphere.

M. Franz: Net Circular Polarization as a tool to measure the gradient with height of the penumbral magnetic field
Abstract Author(s): Franz, M. (1), Borrero, J. M. (1), Schlichenmaier, R. (1)
Institution(s): (1) Kiepeneheuer Institut fuer Sonnenphysik
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 6

We investigate the influence of the gradients with height of various atmospheric parameters on the total net circular polarization (N). In our contribution, we demonstrate that at disk center, the correlation between N and Doppler velocity is larger in down-flow channels than it is in up-flow channels. This is due to a) the larger value of the average zenith angle of the magnetic field in down-flow channels and b) the larger difference between the zenith angles of the magnetic field of the individual atmospheric components (Franz 2011). Furthermore, we argue that only a decrease of the magnetic field strength with optical depth can account for the negative N in the center-side penumbra of sunspots at large heliocentric angles. By means of spectral inversion of Stokes profiles, we show that a simple model atmosphere with linear gradients in Doppler velocity and magnetic field strength is sufficient to account not only for the distribution of N, but also for its amplitude. Our results yield a scenario in which the velocity always increases with optical depth, while the gradient of the magnetic field strength with optical depth is either positive or negative, thereby accounting for the pattern of positive and negative N in the center-side penumbra (Franz et al. 2011).
Franz, M.: 2011, PhD Thesis, Kiepenheuer Institute fuer Sonnenphysik
Franz, M., Borrero, J. M., and Schlichenmaier, R.: 2011, A&A, (in preparation)

P. Heinzel: Visibility of solar prominences in SDO/AIA channels
Abstract Author(s): Heinzel, P. (1), Schmieder, B. (1), Parenti, S. (1), Gunar, S. (1), Golub, L. (1)
Institution(s): (1) Astronomical Institute, Academy of Sciences
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 7

SDO/AIA channels cover an extended range of temperatures and can thus be used todiagnose the transition-region plasmas up to coronal ones. In coronal lines one can seecentral cool parts of prominences as dark structures which is due to absorption and emissivityblocking. In the range of AIA wavelengths, the main contribution to absorption is thephotoionization of HeI and HeII by the coronal line radiation. This allows to determine thecolumn masses of prominences and the ionization degree of helium. An interesting exceptionis the channel around 171 A, where the prominences surprisingly appear inemission, like in 304 channel. In this contribution we first briefly review our previouswork on absorption and blocking and then study the behavior of the 171 emission. We use recently obtained DEM for quiescent prominences and compute the synthetic spectra in selected AIA channels. We then compare 171 and 195 channels and derive conclusions concerning theprominence emissivity, as well well as the absorption and blocking. The emission seen inthe 171 channel can be used to better constrain prominence DEM curves.

Y. Iida: Flux Dependence of cancellation occurrence in Quiet Sun
Abstract Author(s): Iida, Y. (1), Hagenaar, H. (2), Yokoyama, T. (1)
Institution(s): (1) University of Tokyo, Tokyo, Japan, (2) LMSAL, CA, USA
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 8

The frequency of magnetic flux cancellation depends on the flux content of the considered flux elements. This is investigated by using long-term (~140 hours) magnetograms obtained by SOT/FG. Parnell et al. (2009) reported a power-law distribution of flux content with an index of -1.85, which covers a flux range from small patches in quiet Sun to large active regions. This distribution is considered to be achieved and sustained by four magnetic activities, namely emergence, merging, splitting, and cancellation. Though it is important to determine the flux dependence of these activities for the understanding of flux maintenance of the photosphere, there are few reports because of their complexity. Flux dependence of emergence on flux content is reported by Thornton & Parnell (2011). The authors in the Hinode-4th meeting report the flux dependence of merging and splitting. We investigate the flux dependence of cancellation in this study.
The magnetograms obtained by SOT/FG from December 30th in 2008 to January 5th in 2009, whose duration is long enough for a statistical investigation of cancellation, are used. The time interval between magnetograms is five minutes and full field of view is 84"x100". 5973 Cancellations are detected in this data set. Cancellation occurrence rate depends on decreased flux content during cancellation with a power-law index of -2.52. The slope steeper than -2 indicates that tiny cancellations take more important roles in the maintenance of flux distribution. Our findings are combined with the results of previous studies in order to discuss the flux maintenance in quiet Sun.

I. Kitiashvili: Vortex tubes as a source of acoustic emission in quiet Sun
Abstract Author(s): Kitiashvili, I.N. (1), Kosovichev, A.G. (1), Lele, S.K. (1), Mansour, N.N. (2), Wray, A.A, (2)
Institution(s): (1) Stanford University, (2) NASA Ames Research Center
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 9

Observations of the oscillatory behavior of the solar surface provide information about the photospheric and internal dynamics. Combination of observations and realistic radiative hydrodynamic numerical simulations is an excellent tool for a better understanding of the complicated turbulent phenomena on the Sun. Realistic simulations of quiet-Sun convection show a very important role of swirling motions (vortex tubes), which are ubiquitous on the surface and in near-surface layers. Strong vortex events occur often and are better visible in density and pressure variations. Interaction between the vortex tubes is associated with excitation of acoustic waves in a subsurface layer 150-300km deep. In the talk we will discuss various aspects of the vortex tubes dynamics: themechanism of formation, the thermodynamic and flow structure, dynamical properties, and the vortex annihilation process as a source of acoustic waves. We will compare the theoretical results with high-resolution observations.

I. Kitiashvili: Formation of multi-scale structures in solar magnetoconvection and their dynamics
Abstract Author(s): Kitiashvili, I.N. (1), Kosovichev, A.G. (1), Mansour, N.N. (2), Stenflo, J.O. (3), Wray, A.A. (2)
Institution(s): (1) Stanford University, (2) NASA Ames Research Center, (3) Institute of Astronomy ETH Zurich
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 10

Dynamical self-organization phenomena are observed in supergranulation, plage regions, pores and sunspots. Recent progress in computational capabilities allows us to consider various regimes of the solar dynamics based on first physical principles. Realistic radiative MHD simulations help to answer important questions about the physical characteristics of solar magnetoconvection that support processes of magnetic structure formation of various scale. We will discuss results of our numerical simulations from the point of view of spontaneous formation of magnetic structures and self-organization processes on different spatial scales, as well as the role of turbulent vortex tubes in these processes. For comparison with observations we calculate Stokes profiles for the Hinode SP lines and investigate effects of unresolved small-scale turbulent properties.

E. Lim: Photospheric Signature of Granular-scale Flux Emergence and Cancellation
Abstract Author(s): (1) Lim, E.-K., (1) Yurchyshyn, V. (1), Abramenko, V. (1), Ahn, K. (1), Cao, W. (1), Goode, P. (1)
Institution(s): (1) Big Bear Solar Observatory, New Jersey Institute of Technology
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 11

We studied small-scale flux emergence on granular scales in an active region. New Solar Telescope (NST) of Big Bear Solar Observatory made it possible to clearly observe the photospheric signature of flux emergence with very high spatial (0".0375/pix) and temporal (15 s) resolution. From TiO observations, we found several elongated features stretching from the penumbral filaments at a relatively high speed (> 4 km/s). After an arched darkening appeared at a tip of a penumbral filament, a bright point (BP) developed and quickly moved away forming and stretching an elongated feature. Its size was approximately 3" by 0".5. The moving BP encountered nearby structures and a well-defined elongated shape faded away. Magnetograms from SDO/HMI and NST/IRIM showed that those features are associated with small-scale emerging and moving magnetic features, and their disappearance with magnetic cancellation. With two events, we describe detailed morphological developments, and their different cancellation processes.

Y. Matsui: Multi-wavelength observation of EUV jet in AR 10960
Abstract Author(s): Matsui, Y. (1), Yokoyama, T. (1), Imada, S. (2)
Institution(s): (1) Univ. of Tokyo, Japan, (2) Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 12

We report the relationship between the velocity and the temperature of a solar EUV jet. This jet occurred in the active region NOAA 10960 on 2007 June 5. Multi-wavelength spectral observations with EIS/Hinode allow us to know Doppler velocities at the wide temperature range. We analyzed the inclination angle of this jet from the stereoscopic analysis with STEREO. Using this inclination angle and Doppler velocity, we derived the real velocity of the jet. We found: (1) The jet consists of multi-temperature plasmas in a few 10⁴ K to a few MK range. (2) The dependence of velocity upon the plasma temperature shows that the jet has two major components. (3) One component is a hot jet whose velocity is close to the sound speed at temperatures above 1 MK. (4) The other is a cool jet (< 1MK) which has approximately 250 km/s speed and has no dependence on plasma temperature. We interpret that the hot jet is driven by the chromospheric evaporation mechanism because of its temperature dependence and that the cool one is driven by the magnetic Lorentz force because of its super-sonic speed and non-dependence on temperatures. A morphological interpretation of this event is given based on the reconnection model by utilizing the multi-instrumental observations. Discussion of such double driving mechanisms for a jet event is also given along with our recent MHD simulations.

D. Nandi: A Case for Polar Magnetic Field Diagnostics from the Perspective of the Solar Dynamo
Abstract Author(s): (1) N., Dibyendu
Institution(s): (1) Indian Institute of Science Education and Research, Kolkata, India
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 13

The solar cycle involves the recycling of the toroidal and poloidal components of the Sun's magnetic field mediated via various flux transport processes. The toroidal field is produced in the interior of the Sun through stretching of the poloidal component by differential rotation. While there is no consensus on the mechanisms involved in poloidal field creation, recent evidence strongly supports the ideas of Babcock and Leighton — who envisaged that the decay and dispersal of tilted bipolar active regions is the main contributor to the poloidal field. This process, which plausibly constitutes one-half of the dynamo mechanism, occurs at photospheric and near-surface layers and can therefore be observationally constrained. Moreover, recent solar dynamo simulations aimed at exploring the physics of solar cycle predictability point out that the polar field of the preceding cycle is the primary determinant of the strength of the following cycle. Based on these ideas, I will present a case for accurate quantitative diagnostics of the Sun's polar magnetic field.

E. Pedram: CME-related changes in line-of-sight magnetic field strength in dimming regions observed by Hinode on 14 December 2006
Abstract Author(s): Ehsan Pedram (1), Sarah Matthews (1), Lidia van Driel-Gesztelyi (1, 2, 3)
Institution(s): (1) University College London - Mullard Space Science Laboratory, (2) Observatoire de Paris, LESIA, (3) Konkoly Observatory of Hungarian Academy of Sciences
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 14

Following many coronal mass ejections (CMEs), dark areas referred to as coronal dimming regions have been observed to form within and around the erupting active region. We probe the nature of coronal dimmings in relation with the expanding CME though the analysis of their photospheric magnetic field in the flare and CME event of 14 December 2006 using data from Hinode's SOT. We have systematically analysed the variation of the magnetic field strength in a large region surrounding AR 10930 using Hinode SOT stokes V data. Our analysis shows that at the site of the dimmings there is a decrease in the magnetic field strength at the onset of the dimming in the dominant polarity of the plage regions surrounding the AR, persisting during the dimming without recovering to pre-CME values. This finding indicates a permanent reconfiguration and opening of the magnetic field lines as a result of a change in their inclination angle in the dominant polarity of the plage regions surrounding the erupting active region leading to a decrease in the plasma density observed as coronal dimming.

A. Sainz Dalda: Magnetic field topology of pores and naked sunspot
Abstract Author(s): Sainz Dalda, A. (1), Tarbell, T. (2), Title, A. (2)
Institution(s): (1) Stanford-Lockheed Institute for Space Research, Palo Alto , CA, USA, (2) Lockheed Martin Solar and Astrophysics Laboratory, Palo Alto, CA, USA.
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 15

Pores and naked sunspot are well-known solar features for long time ago. However, their magnetic topology and evolution are still unrevealed. Spectropolarimetric data with a high cadence, sensitivity, spatial and spectral resolution taken with the instrument SOT/SP on-board of the satellite Hinode have helped to shed light on them. We present the evolution of the magnetic field vector and thermodynamic magnitudes of a large-sized pore. Numerical simulations use to reproduce naked sunspot and pores as a sunspot without penumbra during either its evolution (naked sunspot) or its full life (pore). Our results offer the values that the model and numerical simulation must explain and reproduce respectively. In addition, paradoxically, the lack of penumbrae in these structures may give us a better understanding of its originating mechanism.

G. Scharmer: Convective flows in a sunspot penumbra
Abstract Author(s): Scharmer, G. B. (1), Henriques, V. M. J. (1)
Institution(s): (1) Institute for Solar Physics of the R. Swedish Academy of Sciences
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 16

We discuss small-scale flows in the interior part of a sunspot penumbra, observed with SST/CRISP at 0.15 arcsec spatial resolution in the CI 5380 and Fe I 6301 lines. Both lines show clear correlation between intensity and vertical velocity, demonstrating the presence of overturning convection. The measured RMS velocities are sufficient to compensate penumbral radiative losses. The relation between the convective flows and the magnetic field topology are discussed.

D. Schmit: Diagnosing the Prominence-Cavity Connection
Abstract Author(s): Schmit, D. (1), Gibson, S. (1)
Institution(s): (1) University of Colorado-Boulder, High Altitude Observatory
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 17

The magnetic field is thought to play a central role in both the support of the prominence as well as the thermodynamic isolation of the surrounding cavity. We use the Hinode/EIS and SDO/AIA datasets to probe for the first time the dynamical link between these related structures. These observations are compared to the 3D magnetic geometries predicted by MHD models. The dynamic features are explained within the context of 1D field-aligned momentum and energy imbalance.

P. Schwartz: Statistics of mass loading of quiescent prominences
Abstract Author(s): Schwartz, P. (1, 2), Heinzel, P. (1), Kotrc, P. (1), Anzer, U. (3), Kupryakov, Yu. A. (4)
Institution(s): (1) Astronomical Institute, Academy of Sciences of the Czech Republic, Ondrejov, Czech Republic, (2) Astronomical Institute, Slovak Academy of Sciences, Tatranska Lomnica, Slovak Republic, (3) Max-Planck-Institut fuer Astrophysic, Garching, Germany, (4) Sternberg Astronomical Institute, Moscow, Russia
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 18

From May through June 2011, a multi-spectral observing campaign of quiescent prominences took place. Observations
were carried out in EUV by AIA/SDO, in soft X-rays by XRT on Hinode (HOP) and in H_alpha by horizontal spectrographs of the Ondrejov observatory. Our aim was to observe a large number of quiescent prominences, in order to make statistics of their total masses. The total mass of each prominence is obtained by integration of the column density of the hydrogen and helium plasma over the whole prominence area. The column density is obtained using semi-automatic code based on the method of Heinzel et al. (2008) and the code is capable of analyzing a large aumount of prominence observations. Moreover, we improved the method by taking into account non-symmetrical distributions of the coronal X-ray and EUV emissivity in front and behind the prominence. H_alpha intensities are used to estimate the hydrogen ionization degree, a very important parameter for the mass-loading determination.

E. Scullion: Understanding chromospheric swirls in the solar corona
Abstract Author(s): Scullion, E. (1), Wedemeyer, S. (1), Rouppe van der Voort, L. (1), Fedun, V. (2), Erdelyi, R. (2)
Institution(s): (1) Institute of Theoretical Astrophysics, University of Oslo, Norway; (2) SP2RC, University of Sheffield, Applied Mathematics Department, UK
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 19 (Digital Poster Display)

Recently discovered, and frequently occurring, chromospheric swirls may play an important role in channelling magnetic energy and plasma from the solar photosphere through to the hot outer solar corona. Spatially confined swirl events where first detected (2009) in the chromospheric Ca-II 854.2nm spectral line with the 1-m Swedish Solar Telescope (SST). Their characteristic vortex motions are believed to be driven by the build up of magnetic tension in the intergranular lanes and forced through photospheric convective buffeting. But, until now, it was unknown (both observationally and numerically) whether there was a coronal counterpart to these swirls. Also, more importantly, is there sufficient energy flux in the swirls to heat the outer atmosphere and contribute to the coronal heating? Here we present unique co-observations of chromospheric swirls, as observed with the SST / CRISP, SDO (Solar Dynamics Observatory) and Hinode (XRT/SOT/EIS) from May 2011. We successfully co-align these observations and reveal the coronal counterpart of swirls. Furthermore, we present a supporting 3D numerical model of swirl formation using a fully non-linear MHD (Magneto-HydroDynamic) code called SAC (Sheffield Advanced Code). We investigate wave propagation (driven by photospheric convection) and subsequent wave transmission through the chromosphere and into the corona. With this study we address an important piece of the puzzle regarding solar swirls with respect to their signature in the solar corona and, henceforth, further our understanding of how small-scale processes (which dominate the solar chromosphere) become coupled into the magnetized corona.

R. Stein: Spontaneous Pore Formation in Magneto-Convection Simulations
Abstract Author(s): Stein, R. (1), Nordlund, A. (2)
Institution(s): (1) Michigan State University/Niels Bohr Institute, (2) Copenhagen University
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 20 (Digital Poster Display)

Pores form spontaneously in simulations of emerging, minimally structured (uniform, untwisted, horizontal) magnetic field from a depth of 20 Mm in a domain 48 Mm wide. The inflow field strength was slowly increased from 200 G to 1 or 5 kG with an e-folding time of 5 hours. The field emerges first in a mixed polarity "pepper and salt pattern", but then due to the underlying large scale magnetic field structure collects into separate, unipolar concentrations. In the 5 kG case a pore formed spontaneously after 19 hours and in the 1 kG case after 44 hours. The pores have both accumulated a magnetic flux of about 2x1020 Mx. The magnetic concentration in the pore first forms near the surface at the edge of a large rising magnetic loop. As time goes in they accumulate more magnetic flux and extend downward, as high magnetic flux, low temperature and low density concentrations, reaching all the way to the bottom of the 20 Mm computational domain. They have a filamentary structure near the surface, but appear more coherent deeper in the interior. The minimum intensity in the pore is 20% of the average intensity and they are edge brightened in parts of their circumference. The magnetic field is vertical in the pore interior and inclined to the vertical at angles greater than 45 deg near their edges. The pores have lasted for over 10 hours so far.Stokes spectra of the Fe I 630.15 and 630.25 nm lines have been calculated and degraded by the Hinode annular psf, the slit diffraction and frequency smoothing for both quiet Sun and plage regions of the simulation.This work has been supported by NASA grants NNX07AO71G, NNX07AH79G and NNX08AH44G and NSF grant AST0605738. The simulations where performed on the pleiades cluster of the NASA Advanced Supercomputing Division at the Ames Research Center.

Y. Su: Structure and Dynamics of the Quiescent Prominence Eruption on 2010 December 6
Abstract Author(s): Su, Y. (1), van Ballegooijen, A. (1)
Institution(s): (1) Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 21 (Digital Poster Display)

We present observations of the quiescent prominence that erupted on 2010 December 6. This prominence contains two parts: one part located in the active region remnants contains mainly horizontal threads, and another part located in the quiet Sun contains mainly vertical threads. Combination of SDO/AIA and STEREO/SECCHI/EUVI allows us to see the fine structures of this prominence both at the limb and on the disk. H-alpha observations from KSO are also included. We focus on the fine structures and dynamics of this prominence before, during, and after the eruption. Prior to the eruption, STEREO shows that filament material frequently ejects from the active region part to the quiet Sun part. This ejection results in the formation of a tree-like structure (concentration of dark vertical threads) near the border between the active region remnants and the quiet Sun. Around 14:18 UT, brightenings appeared around the filament in the active region remnants, which is followed by the lifting off of the filament starting from the center of the active region remnants. Most parts of the filament are erupted except a small fraction near the quiet Sun end. The filament left behind shows vertical threads in SDO/AIA at the east limb, but a thin dark filament on the disk is observed by STEREO/EUVI.

M. Zhang: Hemispheric Helicity Trend for Solar Cycle 24
Abstract Author(s): Hao, J. (1), Zhang, M. (1)
Institution(s): (1) National Astronomical Observatory of China
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 22

Using vector magnetograms obtained with the Spectro-polarimeter (SP) on aboard Hinode satellite, we studied two helicity parameters (local twist and current helicity) of 64 active regions occurred in the descending phase of solar cycle 23 and the ascending phase of solar cycle 24. Our analysis gives the following results. (1) The 34 active regions of the solar cycle 24 follow the so-called hemispheric helicity rule, whereas the 30 active regions of the solar cycle 23 do not. (2) When combining all 64 active regions as one sample, they follow the hemispheric helicity sign rule as in most other observations. (3) Despite with the so-far most accurate measurement of vector magnetic field given by SP/Hinode, the rule is still weak with large scatters. (4) The data show evidence of different helicity signs between strong and weak fields, confirming previous result from a large sample of ground-based observations. (5) With two example sunspots we show that the helicity parameters change sign from the inner umbra to the outer penumbra, where the sign of penumbra agrees with the sign of the active region as a whole. From these results, we speculate that both the Sigma-effect (turbulent convection) and the dynamo have contributed in the generation of helicity, whereas in both cases turbulence in the convection zone has played a significant role.

L. Abbo: Coronal structure and outflow velocities overlaying network and coronal holes
Abstract Author(s): Abbo, L. (1), Gabriel, A. (2)
Institution(s): (1) INAF-Osservatorio Astronomico di Torino, Pino Torinese (TO), 10025 - Italy, (2) Institut d'Astrophysique Spatiale, Université Paris-Sud 11, 91405 Orsay - France
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 23

Outflow velocity maps in quiet Sun and coronal hole regions from EIS/Hinode data have been derived over a range of coronal and transition region temperatures. These are used in order to study effects due to the underlying supergranule network and of coronal holes. To identify clearly the supergranular network and its associated magnetic structure, we have used data from SDO: specifically 1600 Å images from AIA and magnetic fields from HMI. Our observations, together with others published previously (e.g. Hassler et al. 1999), are interpreted in terms of the magnetic field of the network in the transition region, involving the release of energy and leading to the solar wind outflow.

L. Belluzzi: Partial Frequency Redistribution Effects on the Scattering Polarization Pattern of Ly-alpha
Abstract Author(s): Belluzzi, L. (1), Trujillo Bueno, J. (2), Manso Sainz, R. (3)
Institution(s): (1) Instituto de Astrofisica de Canarias
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 24

A very promising diagnostic tool for investigating the magnetic fields of the upper chromosphere and transition region of the Sun is the Hanle effect (i.e. the modification of the linear polarization produced by scattering processes due to the presence of a magnetic field), in the hydrogen Lyman-alpha line.
A deep understanding of the physics of scattering polarization in Lyman-alpha represents the first step in the development of such a diagnostic tool. In particular, it is important to carefully investigate the impact on the linear polarization pattern of this line of partial frequency redistribution effects.
In this contribution, we show some interesting results concerning the expected scattering polarization pattern in the Lyman-alpha line, as obtained taking into account partial frequency redistribution and radiative transfer effects in semi-empirical models of the solar atmosphere.

M. Carbonell: Time damping of non-adiabatic magnetohydrodynamic waves in a partially ionised prominence medium: Effect of a background flow
Abstract Author(s): Barcelo, S. (1), Ballester, J. L. (1)
Institution(s): (1) Dept. Matematiques. Universitat Illes Balears
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 25

The simultaneous occurrence of flows and time damped small-amplitude oscillations in solar prominences is a common phenomenon.These oscillations are mostly interpreted in terms of magnetohydrodynamic (MHD) waves. We study the time damping of linear non-adiabatic MHD waves in a flowing partially ionised plasma with prominence-like physical conditions. While in the case without flow there is a critical wavenumber at which the period of Alfven and fast waves goes to infinite, when a flow is present two different critical wavenumbers appear.
When the second critical wavenumber is attained the period of both branches become equal. In general, the time damping of Alfven and fast waves is dominated by resistive effects, and its damping ratio is very inefficient when compared to observations. The damping of slow and thermal waves is basically dominated by non-adiabatic effects, and for slow waves it is possible to obtain a damping ratio close to observations, although it would correspond to long period oscillations with large damping times not often observed. The consideration of a structured medium produces new features such as the apparition of four critical wavenumbers for Alfven waves, and one critical wavenumber for slow waves. For fast waves, constrained propagation substantially improves, within the range of observed wavelengths, the ratio of the damping time to period. In general, the results point out that ion-neutral collisions are an inefficient mechanism to explain the observed time damping of prominence oscillations if they are produced by Alfven and fast waves. If the oscillations are produced by slow waves, only long period oscillations with large damping times produce damping ratios in agreement with observations.

A. de Wijn: A high-resolution study of Ca II H time-series as observed with Hinode
Abstract Author(s): de Wijn, A. G. (1)
Institution(s): (1) NCAR
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 26 (Digital Poster Display)

I present a study of time series of Ca II H images taken with Hinode/SOT. I identify small bright points that we associate with strong, mostly vertical magnetic field through comparison with G-band imaging and inversions of spectropolarimetric observations. I show that not all magnetic bright points are associated with kiloGauss field. These fields appear bright as a result of optical-depth effects resulting from the Wilson depression, and the emission seen in our observations likely results mostly from the wings of the Ca II H line. There is excellent correspondence between the Ca II H and Fe I 630.15 nm line core intensity, except tenous emission around the network field concentrations in the former that is absent in the latter. Comparison with limb observations shows that this "network haze" most likely corresponds to spicules.

C. Fischer: Flux cancellation events in high-temporal, high-spatial resolution Hinode SOT quiet sun data
Abstract Author(s): Fischer, C. E. (1), deWijn, A. G. (2), Keller, C.U. (3), Lites, B.W. (2)
Institution(s): (1) European Space Research and Technology Centre, ESA, Noordwijk, The Netherlands, (2) High Altitude Observatory, NCAR, Boulder, USA, (3) Astronomical Institute Utrecht, UU , Utrecht, The Netherlands
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 27 (Digital Poster Display)

We analyze a quiet-sun high-temporal, high-spatial resolution spectropolarimetric data set in combination with chromospheric filtergrams and high photosphere magnetograms recorded by the Hinode Solar Optical Telescope (SOT). The data set consists of a 4-hour time series with a field of view of 41 arcsec by 4.8 arcsec and scanned by the SP with a cadence of 1 minute. In addition we retrieve co-temporal and co-spatial Mg I b2 magnetograms and Ca II H filtergrams. We search for signatures of flux cancellation events and characterize their temporal evolution at different atmospheric heights. We find 33 flux cancellation events, with 25 showing a horizontal magnetic flux component located between the opposite polarity patches during the cancellation process.

V. Hansteen: Comparisons of observed and simulated umbral dots
Abstract Author(s): Hansteen, V. (1), Ortiz, A. (1)
Institution(s): (1) Institute of theoretical astrophysics, University of Oslo
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 28

We study and compare the properties of observed and simulated umbral dots (UDs). The observations were made at a spatial resolution of 0.14 arcsec and contain full Stokes measurements of a pore taken with the Crisp Imaging Spectro-Polarimeter at the Swedish 1 m Solar Telescope (Ortiz et al., 2010). We determine the general appearance, temporal evolution and flow velocity at different heights in the photosphere from a bisector analysis of the Fe I 630 nm lines. In addition, we use Stokes Q, U, and V profiles to characterize the magnetic properties of these structures. We find that most UDs are associated with strong upflows in deep photospheric layers. Some of them also show concentrated patches of downflows at their edges, with sizes of about 0.25 arcsec, velocities of up to 1000 m/s, and enhanced net circular polarization signals. These results are compared to Bifrost numerical models of magnetoconvection in the presence of strong magnetic fields, where we also can describe the general structure and evolution of the simulated UDs both in the convection zone below the photosphere and into the chromosphere above the photospheric UDs.

N. Hurlburt: A comparison of flow patterns around coronal structures as observed by Hinode and SDO
Abstract Author(s): Hurlburt, N. (1)
Institution(s): (1) Lockheed Martin/ATC
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 29 (Digital Poster Display)

Large scale flows in the vicinity of filaments, coronal holes and active regions are investigated. We identify sets of each over the year of past year using the Heliophysics Events Knowledgebase (HEK). Surface velocities are extracted from SOT and HMI data cubes using a spectral optical flow method and there properties are compared, both to assess the relative accuracy of the derived flows and to compare with coronal observations of AIA and XRT.

K. Ichimoto: Structure of the inverse-Evershed flow in sunspots observed by SOT
Abstract Author(s): Ichimoto, K. (1)
Institution(s): (1) Kyoto University
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 30

The Solar Optical Telescope (SOT) aboard Hinode revealed the nature of the fine scale structure and dynamics of sunspot penumbra with the unprecedentedly stable high resolution imaging and high precision spectropolarimetory. The radial filamentary structure of penumbra and the conspicuous photospheric outflow known as the Evershed effect are understood as a natural consequence of thermal convection under the influence of strong sunspot magnetic fields. The interlocking structure of penumbral magnetic field, in which the elevation angle of magnetic field vector changes alternatively along the azimuthal direction with the spatial scale of the filament width, are demonstrated, where the Evershed outflow takes place along nearly horizontal field channels. Higher in the atmosphere, there is a reversed flow toward the umbra known as the inverse Evershed flow, while the nature nor the origin of which is still unknown. The SOT/NFI Dopplergram in the core of NaD1 line shows filamentary structures of oppositely directed Doppler signals over the penumbra. In this paper, we present the spatial structure of the inverse Evershed effect in relation to the penumbral interlocking field structure and its temporal behavior. A possible mechanism that drives the inverse Evershed flow will also be discussed.

J. Joshi: Overturning Convection in Sunspot Penumbra: Observation in Deep Photospheric Spectral Line C I 5380
Abstract Author(s): Joshi, J. (1)
Institution(s): (1) Max-Planck Institute for solar system research, Katlenberg-Lindau, Germany
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 31

We observed a sunspot in active region NOAA 11113 with the 1-meter SwedishSolar Telescope (SST) on 2010, October 17. Sunspot was located at heliocentric angle of 28 and spectropolarimetric observation was made in Deep photospheric C I 5380 and mid photospheric Fe i 5250 spectral lines. We study overturning convectionin the sunspot penumbra. Recent high resolution observations in Deep photosphericC i 5380 line has found direct evidence of overturning convection in penumbra(Joshi et al., 2011; Scharmer et al., 2011) and support that heat transport in sunspotpenumbra is accomplished by overturning convection. Three-Dimensional radiativeMHD simulations suggest that convective structure in penumbrae restricted at surfaceand sub-surface layers. Results from comparison of velocity structure of the sunspotpenumbra in mid and deep photosphere will be presented. Properties of convectivemotion along the axis penumbral filaments will be studied and compared with twist-ing motion of penumbral filaments to establish relation between twisting motion andoverturning convection.

Y. Katsukawa: Power spectra of the solar surface convection and implication to local dynamo
Abstract Author(s): Katsukawa, Y. (1), Orozco Suarez, D. (1)
Institution(s): (1) National Astrnomoical Observatory of Japan
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 32

On the solar surface, interaction between magnetic fields and surface convection produces varieties of structures over the broad spatial scale from ~100 km, such as thin flux tubes, to 10⁵ km, such as sunspots and active regions. Spatial power spectra of velocity and magnetic fields on the solar surface provide a clue to understand in which scale kinetic and magnetic energies are generated, transferred, and dissipated in the solar atmosphere. The HINODE Solar Optical Telescope (SOT) is the most suitable instrument to study it observationally owing to stable image quality, especially at the scale smaller than granulation. We made the power spectra using spectro-polarimeter (SP) data separately in internetwork and network regions as a function of mean unsigned magnetic flux. When the unsigned flux is very weak (<10 G), i.e. in the internetwork regions, the power spectra of magnetic energies have a peak at ~700 km which is comparable with the granular scale. At the scale smaller than granulation, the power spectrum exhibits power-law distribution with an index of ~ -1.3. Numerical simulations of granular convection indicated that magnetic fields were created by local dynamo action at the spatial scale smaller than the observational resolution limit, and magnetic energies at the scale dominated the overall magnetic energies. But the power spectrum derived in our study is inconsistent with them, because the magnetic energies tend to be suppressed at the scale smaller than 500 km. When the unsigned flux is large (>100 G), on the other hand, the power spectra of kinetic and magnetic energies tend to exhibit less clear peak at the granulation scale, but have a single power-law distribution, which implies that kinetic and magnetic energies strongly interact each other at every spatial scale.

M. Kubo: Comparing Photospheric Magnetic Fields and Subsurface Flows in the Quiet Sun
Abstract Author(s): Kubo, M. (1), Sekii, T. (1), and Gizon, L. (2,3)
Institution(s): (1) National Astronomical Observatory of Japan, Tokyo, Japan, (2) Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany, (3) Institute for Astrophysics, University of G
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 33 (Digital Poster Display)

Magnetic fields are dominated by the fluid immediately below the quiet-Sun photosphere. Therefore, it is expected that the magnetic field distribution is controlled by the convective motions. Magnetic concentrations that have vertical and strong fields are observed along the boundaries of the convective cells. A most prominent feature in the quiet Sun is the network magnetic field that partially outlines supergranular cells. It is believed that the network magnetic field is formed by the advection of intranetwork fields via the supergranular flows. On the other hand, spectropolarimetric observations using the Solar Optical Telescope (SOT) reveal that the quiet intranetwork regions are pervaded by horizontal magnetic fields. Information about subsurface convective flows would be helpful for understanding the organization of magnetic fields on the solar surface. We compare the photospheric magnetic field vector with the subsurface supergranular flows. The magnetic field vector is derived from the spectropolarimetric measurements with the Hinode/SOT. Our target is a quiet region around disk center. The field-of-view of 160"x160" includes several supergranular cells. The subsurface flow patterns are inferred using (time-distance) helioseismology and a time series of Dopplergrams. The Dopplergrams are observed at a 45-second cadence by the Helioseismic and Magnetic Imager onboard Solar Dynamics Observatory. Larger magnetic concentrations with vertical and stronger fields are observed in the region where the subsurface converging flows at supergranular scale are dominant. This confirms that the network magnetic fields are advected by the supergranular flows. Some stronger horizontal fields in the converging regions coincide with the stronger vertical fields. Such horizontal fields are presumably associated with the magnetic canopy above supergranules. However, stronger horizontal magnetic fields are observed not only in the region of subsurface converging flows but also in the region of diverging flows, an observation for which we have no explanation.

T. Kucera: Temperature Structure of a Coronal Cavity
Abstract Author(s): Kucera, T. A. (1), Gibson, S. E. (2), Schmit, D.J. (3,2)
Institution(s): (1) NASA/GSFC, (2) NCAR/HAO, (3) U. Colorado
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 34

We analyze the temperature structure of a coronal cavity observed in Aug. 2007. Coronal cavities are long, low-density structures located over filament neutral lines and are often seen as dark elliptical features at the solar limb in white light, EUV and X-rays. When these structures erupt they form the cavity portions of CMEs. It is important to establish the temperature structure of cavities in order to understand the thermodynamics of cavities in relation to their three-dimensional magnetic structure.

To analyze the temperature we compare temperature ratios of a series of iron lines observed by the Hinode/EUV Imaging Spectrometer (EIS). We use those lines to constrain a forward model of the emission from the cavity and streamer. The model assumes a coronal streamer with a tunnel-like cavity with elliptical cross-section and a Gaussian variation of height along the tunnel length. Temperature and density can be varied as a function of altitude both in the cavity and streamer. The general cavity morphology and the cavity and streamer density have already been modeled using data from STEREO's SECCHI/EUVI and Hinode/EIS (Gibson et al. 2010 and Schmit & Gibson 2011).

B. Lites: The AZAM Disambiguity Utility for the Hinode Spectro-Polarimeter
Abstract Author(s): (1) Lites, B. W.
Institution(s): (1) HAO/NCAR
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 35

The AZAM utility is a software package for interactive resolution of the 180 ambiguity of the transverse component of the magnetic field vector. In addition to this capability, AZAM also provides the user with a platform that performs many other useful tasks involving examination and display of the results of inversion of solar Stokes profile measurements. Developed initially during the mid‐1990s for use on data from the HAO/NSO Advanced Stokes Polarimeter (SP) and written entirely in IDL, AZAM has been extensively modified to work with data from the Hinode Spectro-Polarimeter. It is implemented in SolarSoft, and will soon be available for use by the community. The interactive ambiguity resolution procedure of AZAM is based on attaining continuity of the field vector over the observed field of view. The present version of AZAM for Hinode SP accepts as an input the routine inversion results from the MERLIN implementation of the Unno-Rachkovsky solution to the equations of polarized radiative transfer for a Milne-Eddington model atmosphere — inversion results produced routinely for all SP data.

J. Martinez-Sykora: Emergence and disappearance of magnetic field in the quiet Sun at the photosphere
Abstract Author(s): Martinez-Sykora, J. (1)
Institution(s): (1) Lockheed Martin Solar & Astrophysics Lab, Palo Alto, CA, USA, (2) Institute of theoretical astrohpysics, University of Oslo, Norway, (3) Instituto Astrofisico de Andalucia, Granada, Spain
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 36

We studied characteristics and statistics of strong asymmetric profiles in Stokes V in quiet sun, using Hinode/SOT, and compare with synthetic observations; i.e., single lobe profiles in Stokes V. These profiles require the existence of a velocity gradient along the line of sight, possibly associated with gradients of magnetic field strength, inclination and/or azimuth. However, these asymmetric profiles do not depend on the velocity or/and sign of the velocity. In the quiet sun, magnetic field is continuously emerging and disappearing at small scales due to the convective motions and the input of new flux from deeper layers. From the realistic simulations, using Bifrost code, we note that most of these small scale processes have stratifications with gradients of magnetic field strength, inclination and velocities. As a consequence, these stratifications are associated with the existence of single-lobe Stokes V profiles in the solar photosphere. We show that most of these profiles come from magnetic flux emergence and disappearance in small scales in the simulations. Most of the stratifications show jumps in the magnetic field configuration. Finally, we emphasize the importance of statistic analysis in these single-lobe Stokes V profiles using Hinode/SOT and the comparison with the synthetic profiles from the simulations. This comparison will ultimately improve the realism of the simulations and quantify the flux emergence and disappearance in the quiet sun.

K. Nagashima: Time-distance helioseismology analyses of multi-wavelength datasets obtained with Hinode/SOT and SDO/HMI
Abstract Author(s): Nagashima, K. (1), Zhao, J. (1), Duvall, Jr., T. (2), Kosovichev, A. G. (1), Parchevsky, K. (1), Sekii, T. (3)
Institution(s): (1) Stanford University, (2) NASA Goddard Space Flight Center, (3) NAOJ
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 37

Helioseismology analysis is useful for probing the interior structure and dynamics of the Sun. Its usefulness, however, is not limited to sub-surface diagnostics. When we use multi-layer observation datasets, it provides us with an opportunity to examine the wave propagation between the layers (Nagashima et al. 2009), and also the oscillation physics of the solar atmosphere. We use multi-wavelength observations from Hinode/SOT and SDO/HMI to carry out the time-distance helioseismology analysis: we calculate the cross-correlation function of the wavefields, measure the travel times of acoustic waves, and investigate the wave-field properties. Our preliminary results reveal differences in the cross-correlation functions and travel times between different observation layers (wavelengths). Investigation of the differences is particularly important for helioseismology analyses of the solar polar regions, because for the polar observation datasets the line formation height may depend on the distance from the disk center even for the case of the single-wavelength observation, and may cause systematic uncertainties in meridional flow measurements by local helioseismology. For a better understanding of the observational results, we use numerical simulations of solar oscillations.

L. Rouppe van der Voort: High-resolution observations of type II spicules
Abstract Author(s): Rouppe van der Voort, L. (1)
Institution(s): (1) University of Oslo
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 38 (Digital Poster Display)

Type II spicules are a class of spicules that are characterized byshort lifetimes and high apparent velocities. Combined with theirnarrow spatial widths, type II spicules are challenging to observe. Weuse the CRISP imaging spectropolarimeter at the Swedish 1-m SolarTelescope on La Palma to observe type II spicules at the limb andtheir counterparts on the solar disk, the so-called "RapidBlue-shifted Excursions" (RBEs). The combination of adaptive opticsand image post-processing allows CRISP to attain high resolutionsimultaneously in the spatial, temporal and spectral domains. Here wepresent results from the analysis of several high-quality data setswhich allow to constrain the physical properties of type IIspicules.

B. Schmieder: On the nature of prominence bubbles and plumes
Abstract Author(s): Schmieder, B. (1), Heinzel, P. (1), Zapior, M. (1), Gunar, S. (1)
Institution(s): (1) Observatoire de Paris-Meudon
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 39 (Digital Poster Display)

A hot topic recently discussed is the nature of large prominence bubbles seen in variousspectral lines, including H-alpha and CaII where they appear as dark features (Berger et al.).However, in selected SDO/AIA coronal channels they usually appear brighter relative to surrounding dark structures. The latter are due to absorption and emissivity blocking of the respective coronal-line radiation. The question is whether the bubbles in these AIA channels are hotter and/or denser compared to surrounding corona or coronal cavity. In this contribution we investigate some examplesof bubbles and related plumes, using the time series in selected SDO/AIA channels and co-temporal MSDP observations in the H-alpha line obtained at Wroclaw-Bialkow observatory.

J. Stepan: An abrupt magnetization in the upper chromosphere of the quiet Sun
Abstract Author(s): Stepan, J. (1), Trujillo Bueno, J. (1), Ramelli, R. (2), Bianda, M. (2)
Institution(s): (1) Instituto de Astrofisica de Canarias, Spain, (2) Istituto Ricerche Solari Locarno, Switzerland
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 40

The only way to obtain quantitative empirical information on the strength and orientation of the magnetic field of the solar atmosphere is through the measurement and interpretation of the polarization signals that some physical mechanisms introduce in spectral lines. Unfortunately, the Zeeman effect as a diagnostic tool is of limited practical interest for the "measurement" of the magnetic fields of the quiet solar chromosphere. Here we show that the Hanle effect in strong spectral lines is the physical mechanism that should be increasingly exploited for quantitative explorations of the magnetism of the quiet solar chromosphere. To this end, we show how scattering polarization observations of the H-alpha line can be modelled by means of multilevel radiative transfer simulations in magnetized atmospheric models. Of particular interest is that the amplitude and shape of the scattering polarization profiles of the H-alpha line are very sensitive to the strength and structure of the chromospheric magnetic field. We show that the interpretation of the available observations in terms of one-dimensional radiative transfer modeling suggests that there is an abrupt and significant magnetization in the upper chromosphere of the quiet Sun.

L. Tarr: Calculating Magnetic Free Energy Using the Minimum Current Corona Model in Evolving Active Regions: NOAA AR11158
Abstract Author(s): Tarr, L. (1), Longcope, D. (1)
Institution(s): (1) Montana State University
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 41 (Digital Poster Display)

The Minimum Current Corona (MCC) model provides a way to estimate stored coronal energy using the number of field lines connecting regions of positive and negative photospheric flux. MCC assumes that the amount of flux connecting pairs of regions is fixed, even as the photospheric field evolves. As the fixed flux in each domain becomes increasingly different from a potential field configuration the system builds up magnetic free energy. We have developed a method for quantifying the field evolution by tracking photospheric magnetic sources measured with SDO/HMI, and therefore energy storage. In particular, we present an algorithm quantifying the flux evolution of each pair of regions due to emergence through the photosphere. We have applied this method to calculate the increase in magnetic free energy in NOAA Active Region 11158, which underwent a GOES X2.2 class flare around 02:00 on Feb.$15^{hbox{scriptsize th}}$, 2011.This work was supported NASA LWS.

R. Thierry: Some dynamic analysis of the Photosphere with HINODE/SOT and SD0
Abstract Author(s): Roudier, T. (1), Malherbe, J. M. (2), Rieutord, M. (1), Berger, T. (3), Frank, Z. (3), Prat, V. (1), Renon, N. (4), Gizon, L. (5), Svanda, M. (5) Max-Planck-Institut für Sonnensystemforschung Max-Planck-Strasse 2,37191 Katlenburg-Lindau, Germany
Institution(s): (1) IRAP Univ. de Toulouse,CNRS,14 avenue E. Belin, 31400 Toulouse, France, (2) LESIA, Observatoire de Paris, Section de Meudon, 92195 Meudon, France, (3) Lockheed Martin Advance Technology Center, Palo Alto, CA, USA, (4) CALMIP, DTSI Université Paul Sabatier, Université de Toulouse 31062 Toulouse, France,
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 42 (Digital Poster Display)

The dynamics of the solar surface and its interaction with the magnetic structures control in great part the outer atmosphere of the Sun. We study the interactions of velocity scales on the Sun's surface, from granulation to supergranulation and their interaction with magnetic fields. We analyse a 48 h time sequence of the quiet Sun photosphere obtained with the Solar Optical Telescope onboard HINODE. This analysis allows us to better characterize Trees of Fragmenting Granules issued from repeated fragmentation of granules. We show their crucial role in the advection of the magnetic field and in the build up of the network. These results demonstrate that the long living families contribute to the formation of the magnetic network and suggest that supergranulation could be an emergent length scale building up as small magnetic elements are advected and concentrated by TFG flows. Observations have been obtained on September 4, 2010, by SOT on board of the satellite HINODE, in magnetically insensitive FeI 557.6 nm line. Acoustic events (AE, defined as spatially concentrated propagating waves) have been derived from amplitudes and phases of vertical Doppler with outstanding spatial resolution (0.3) and field of view. AE partly contribute (10%) to energy transport involved in the chromospheric heating and could be the drivers of the solar oscillations. Very recent observations of HINODE/SOT and SDO/HMI have allowed us, with the HMI-continuum data, to measure the horizontal (vx,vy) all over (almost) the solar surface. These velocity fields are calculated every 30 minutes with spatial window of 2.5 Mm.

S. Jaeggli: Comparison of multi-height observations with a 3D MHD sunspot model
Abstract Author(s): Jaeggli, S. A. (1), Lin, H. (1), Rempel, M. (2), Uitenbroek, H. (3)
Institution(s): (1) Institute for Astronomy - University of Hawaii, (2) High Altitude Observatory, National Center for Atmospheric Research, (3) National Solar Observatory/Sacramento Peak
Session: Magnetic structuring of the Sun from beneath the photosphere through the corona
Poster #: 43

In sunspots the contribution to the horizontal pressure support from the curvature force and the geometrical height of formation which magnetic field measurements sample are poorly constrained observationally due to the effect of radiative transfer. In cool atmospheres, observations of the sunspot photosphere probes geometrically deeper layers, information on the magnetic field gradients cannot be easily derived even using multi-wavelength, multi-height observations. Recent MHD atmosphere models of sunspots analyzed with the Rybiki-Hummer radiative transfer code allow for direct comparison with simultaneous multi-height observations of the Fe I magnetic field diagnostics at 1565 and 630.2 nm in sunspots observed using the Facility Infrared Spectropolarimeter at the Dunn Solar Telescope.

I. Arregui: Inversion of physical parameters in coronal magnetic structures
Abstract Author(s): Arregui, I. (1), Ballester, J.L. (1), Goossens, M. (2), Oliver, R. (1), Asensio Ramos, A. (3)
Institution(s): (1) Universitat de les Illes Balears, Spain, (2) Katholieke Universiteit Leuven, Belgium, (3) Instituto de Astrofisica de Canarias, Spain
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 44 (Digital Poster Display)

Magnetohydrodynamic seismology aims to determine difficult to measure physical parameters in the solar corona by a combination of observed and theoretical properties of waves and oscillations. We first describe relevant examples of the application of seismology techniques to transversely oscillating coronal loops, observed by TRACE, and prominence fine structures, observed by Hinode. We next show how the use of statistical techniques based on Bayesian inference, in combination with Markov chain Montecarlo simulations, can constrain difficult to measure physical parameters. An example is provided in which a bayesian inference technique is applied to transverse coronal loop oscillations. The bayesian approach enable us to infer the most probable values of the relevant parameters, for given observed periods and damping times, and to extract their confidence levels incorporating observed uncertainties in a consistent manner. We believe the development of this kind of technique will be of high value for the future of solar atmospheric seismology, when the inversion of physical parameters will be based on the combination of large scale numerical parametric results and the analysis of data sets obtained from, e.g., SOLAR-C.

M. Hahn: Differential Emission Measure Analysis of a Polar Coronal Hole During the Recent Solar Minimum
Abstract Author(s): Hahn, M. (1), Landi, E. (1), Savin, D. W. (1)
Institution(s): (1) Columbia University
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 45

We have performed a differential emission measure (DEM) analysis for a polar coronal hole observed during the solar minimum in 2007. The analysis was performed for the above-limb portions of five observations from the EUV Imaging Spectrometer on Hinode. The slit pointings also included quiet Sun corona near the boundary with the coronal hole. The analysis shows that the plasma is not strictly isothermal anywhere, but rather has a high-temperature component that extends up to log T(K) = 6.2 - 6.3. The size and importance of this component depend on location and its evolving magnitude marks the boundary between the coronal hole and the quiet corona, where it becomes dominant. Our results highlight the potential limitations of isothermal analyses. Such methods actually measure a DEM-weighted average temperature and as a result can infer artificial temperature gradients. The isothermal analyses also do not detect different structures along the line-of-sight, which can affect the interpretation of density diagnostic line ratios.

H. Hudson: EVE non-detection of Doppler-shifted He II 304 Å
Abstract Author(s): Hudson, H. (1), Fletcher, L. (1), MacKinnon, A. (1), Woods, T. (1)
Institution(s): (1) SSL, UC Berkeley
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 46

The Extreme-ultraviolet Variability Experiment (SDO) gives a new perspective onthe EUV spectroscopy of solar flares, with several new insights. The spectrahave 10-s cadence, excellent dynamic range, and spectral resolution adequateto measure Doppler motions subject to Sun-as-a-star limitations. In thispresentation we describe the search for broad wings in the He II 304 Å line, in which the Orrall & Zirker (1976) mechanism suggests broad Doppler-shiftedwings resulting from charge exchange. The EVE data provide excellent limitson the intensity of such line wings and thereby suggest that alpha particlesdo not significantly penetrate to un-ionized atmospheric regions. Thedata thus far analyzed include two gamma-ray events and two X-class flares.

N. Kitagawa: Power-law index of nanoflares in a coronal loop modified by observational conditions
Abstract Author(s): Kitagawa, N. (1), Yokoyama, T. (1)
Institution(s): (1) The University of Tokyo
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 47

One-dimensional numerical simulation of an impulsively heated coronal loop was conducted. Since Parker (1983) had suggested topological dissipation of coronal magnetic fields braided by photospheric convection, a number of studies has been investigated the validity of coronal heating by that mechanism called ``nanoflare'' (Parker 1988). From observations, it was indicated that the occurrence frequency distribution of solar flares, including major flare (E~1033 erg) down to nanoflare (E~1024 erg), obeys to power-law with an index of around -1.6 (see review by Aschwanden & Parnell 2002). However, in consideration of the result shown by Shimizu (1995) that the power-law distribution becomes flat when spatial resolution is reduced, a value of the index from previous observations may not be conclusive. In addition, temporal cadence, the angle between our line of sight (LOS) and loop plane, and the detection algorithm of heating signatures are likely to influence on the derived power-law index of observations. We have tackled to this issue by using one-dimensional simulation of a coronal loop heated by impulsive energy input representing nanoflare. The energy input obeys to a power-law distribution with the index of 1.6, 2.0, 2.4. Synthesized data observed with TRACE were made through reduced temporal cadence (10s-120s) and spatial resolution (0.5''-4''). Our findings indicate that the derived thermal energy distribution is influenced by spatial resolution rather than temporal cadence, and the methodological difference produces different type of the derived distribution, and LOS angle against loop plane also influences the shape of the derived distribution.

Y. Ko: Properties in the North and South Polar Coronal Holes in the Ascending Phase of Solar Cycle 24, and Comparison with the Associated Solar Wind
Abstract Author(s): Ko, Y.-K. (1), Young, P. R. (1,2), Wang, Y.-M. (1), Warren, H. P. (1)
Institution(s): (1) Naval Research Laboratory, Washington, DC, USA, (2) George Mason University, Fairfax, VA, USA
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 48

Polar coronal holes (CHs) are the most prominent open-field regions on the Sun during the years around solar minimum when solar wind emanating from the high-latitude polar CHs can often reach the ecliptic and measured in-situ by solar wind instruments at 1 AU. In addition, the off-ecliptic trajectory of Ulysses has offered a unique opportunity for measuring the solar wind from deep within the polar CH. It has been found from the Ulysses 1st pole-to-pole fast scan, which was during the descending phase of Cycle 22, that the fast wind ion composition from the north polar CH is "cooler" than that from the south polar CH. On the other hand, recent work on the solar wind with polar CH source regions shows that during the descending phase of Cycle 23, it is the south polar CH that is "cooler". Such intriguing differences should be closely related to the properties intrinsic in these CHs that can be investigated by magnetic and spectroscopic observations. This motivated a series of Hinode observations on polar CHs (HOP146) that intend to look for clues for such differences. We present the physical properties in the north and south polar CHs, as well as their boundary region, derived from Hinode/EIS observations from Dec.2009 to Aug.2010. We discuss the differences between the two CHs and the variations with time. The properties of the solar wind that can be traced back to either polar coronal hole during this period are also presented and compared with these EIS observations.

E. Lee: Statistical Analysis of EIS spectra in Active Regions
Abstract Author(s): Lee, E. (1), Williams, D. R. (1), Lapenta, G. (1)
Institution(s): (1) Katholieke Universiteit Leuven
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 49

In our study, we apply statistical and functional methods to assess the underlying motions in coronal active regions that give rise to the different shapes of emission line profiles seen in spectroscopic images observed by Hinode/EIS. We observe the evolution of 1" slit raster data at multiple coronal temperatures, in different subregions, and during different events, including flux emergence. Assuming the emission line profiles to be a credible proxy for the statistical ensemble of the coronal plasma, we employ a set of tools on the profiles to derive conclusions about its motion along the line of sight. Our tools include both "objective" and "biased" ways of improving the availability of information inferable from EIS observations, without over-constraining the data with ad-hoc assumptions. We compare several methods for improving to the signal-to-noise ratio in our statistics and show the effect of each on data selection. Spectroscopic simulations (akin to synthetic spectra) are also performed to better assess the motion of the plasma and the effects of flux emergence and magnetic reconnection.

W. Liu: Heating of Flare Foops During a Two-ribbon Flare on 2011 March 07
Abstract Author(s): Liu, W-J (1); O'Hara, J. (1, 2); Peck, C. (1); Qiu, J (1); Longcope, D. W. (1)
Institution(s): (1) Montana State University, Bozeman, (2) St Andrews University
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 50

Many eruptive flares exhibit two extended ribbons in the lower-atmosphere outlining the feet of the post-flare coronal arcade. High-cadence and high-resolution UV observations by TRACE reveal that the flare ribbon consists of small patches sequentially brightened along the ribbon, suggesting that reconnection takes place sequentially forming individual post-flare loops along the arcade, as often seen in coronal observations in the EUV wavelengths. These reconnection events and formation of new loops continue well into the decay phase. Our recent study (Qiu et al. 2010) further shows that the spatially resolved UV brightness at the foot-points of individual loops grows rapidly on timescales of a few minutes, followed by a long decay on timescales of more than 10 minutes. The rapid rise of UV radiation is correlated with the hard X-ray light curve during the impulsive phase, hence is most likely a direct response of instantaneous heating in the reconnection formed flux tubes. In this study, we utilize the spatially resolved UV brightness time profiles to reconstruct instantaneous heating functions of individual flux tubes, and compute evolution of each flux tube using the EBTEL model (Klimchuk et al. 2008). The temperature and density of these flux tubes are then used to calculate light curves in other energy bands and compare favorably with observations by RHESSI, GOES and AIA. This study presents the first effort to constrain heating functions of flare loops directly using all available observables, and provides a powerful way to examine physics of heating discrete flux tubes formed by reconnection events throughout the flare.

M. Miralles: Propagation of Polar Coronal Jets in the Fast Solar Wind
Abstract Author(s): Miralles, M. P. (1), Cranmer, S. R. (1), Raymond, J. C. (1), Savcheva, A. S. (1), Stenborg, G. (2), Deluca, E. E. (1)
Institution(s): (1) Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA, (2) Interferometrics Inc., Herndon, VA, USA
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 51

We present results of an ongoing observational study of the physical properties and kinematics of polar coronal jets. While magnetic reconnection is considered the prime driving mechanism of the ejected plasma, the processes at work during reconnection are not yet completely understood. We use a combination of X-ray, UV, and visible-light imaging to probe the jet plasma, and we trace polar jets from their reconnection sites into the fast solar wind. Multi-instrument measurements of polar jets will put firm constraints on the mechanisms driving the jets and on the relative contribution of jets to the overall fast solar wind.
This work is supported by NASA grant NNX09AH22G to the Smithsonian Astrophysical Observatory.

R. Moore: What Powers Coronal Heating and the Solar Wind According to Hinode
Abstract Author(s): (1) Ron Moore, (1) Alphonse Sterling, (1) Jonathan Cirtain, (1) David Falconer
Institution(s): (1) NASA/Marshall Space Flight Center/NSSTC
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 52

From Hinode’s ground-breaking high-resolution observations of solar X-ray jets, Type-II spicules, and granule-size emerging bipolar magnetic fields in quiet regions and coronal holes, we advocate a scenario for powering coronal heating and the solar wind. In this scenario, Type-II spicules and Alfven waves are generated by granule-size emerging bipolar magnetic fields in the manner of the generation of X-ray jets and accompanying Alfven waves by larger magnetic bipoles. From observations and this scenario, we estimate that Type-II spicules and their co-generated Alfven waves carry into the corona an area-average flux of mechanical energy of about 7 x 10⁵ erg cm^-2 s^-1. This is enough to power the corona and solar wind in quiet regions and coronal holes. Therefore, the discoveries by Hinode of Alfven waves in X-ray jets, Type-II spicules, Alfven waves in Type-II spicules, and granule-size emerging bipoles, together indicate that the granule-size emerging bipoles, by making Type-II spicules, are the main power source of coronal heating, the solar wind, and hence the entire heliosphere. Thus, provided that coordinated high-resolution observations confirm that Type-II spicules come from the granule-size emerging bipoles, Hinode has discovered the specific magnetic activity that powers the global corona and solar wind.
This work was funded by NASA’s Science Mission Directorate through the Heliophysics Guest Investigator’s Program, the Hinode Project, and the Living With a Star Targeted Research and Technology Program.

N. Narukage: Diagnostics of coronal temperature based on the calibration result of X-Ray Telescope and further calibration
Abstract Author(s): Narukage, N. (1), Sakao, T. (1), Kano, R. (2), Shimojo, M. (2)
Institution(s): (1) Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA), Sagamihara, Kanagawa, JAPAN, (2) National Astronomical Observatory of Japan (NAOJ), Mitaka, Tokyo, JAPAN
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 53

The X-Ray Telescope (XRT) onboard the Hinode satellite is an X-ray imager that observes the solar corona with nine X-ray analysis filters which have different temperature responses. One of the most significant scientific features of this telescope is its capability of diagnosing coronal temperatures from less than 1 MK to more than 10 MK. To make full use of this capability, Narukage et al. (2011) calibrated the coronal temperature response of XRT including the effect of on-orbit contamination. They showed that, for some filter pairs, there is a discrepancy between the filter-ratio temperatures with the calibrated result and with the instrumental parameters before calibration. In this paper, we investigate whether the results of coronal temperature diagnostics before the calibration are appropriate, i.e., are comparable to the filter ratio temperature based on the calibration result. For example, though Reale et al. (2009) showed the presence of plasma around 10 MK in a non-flaring coronal active region with the filter ratio of med-Be and med-Al filters, we find that its temperature should be around 2 MK.Meanwhile, the filter ratio temperature in flare derived with calibrated thick filters (thick-Al and thick-Be) is around 3 or 4 MK, which is cooler than the expected temperature. As described in Narukage et al. (2011), the calibration of thick-Al and thick-Be filters is not enough, since only one characteristic X-ray line was available in the ground-based calibration because of little transmission of low-energy X-rays for the thick filters. In this paper, we calibrate these thick filters with the data sets of active regions.

J. Plowman: DEMs for EIS and AIA
Abstract Author(s): Plowman, J. (1), Martens, P. (1), Ritchie, M. (2), Scott, J. (1), Sharma, R. (3)
Institution(s): (1) Montana State University, Bozeman, MT, USA, (2) University of St Andrews, Scotland, UK, (3) Mohanlal Sukhadia University, Rajasthan, India
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 54

We present a method for constructing Differential Emission Measures (DEMs) using data from solar imagers such as EIS and AIA, and apply it to a coronal loop observed on April 19, 2011. The performance of our DEM inversion is compared to other methods, and the ability of such inversions in general to faithfully reproduce a set of test temperature distributions is analyzed. We also compare the observed loop temperature distributions to an analytic strand heating model developed by Martens (2010).

F. Reale: Hot plasma detected in active regions by Hinode/XRT and SDO/AIA
Abstract Author(s): Reale, F. (1), Testa, P. (1), Guarrasi, M. (1), De Luca, E.E. (1), Peres, G. (1), Golub, L. (1)
Institution(s): (1) University of Palermo
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 55

Multiple ratios of Hinode/XRT filters showed evidence of a minor very hot emission measure component in active regions. Recently also SDO/AIA detected hot plasma in the core of an active region. Here we provide estimations that the amount of emission measure of the hot component detected with SDO is consistent with that detected with Hinode/XRT.

A. Reva: Simultaneous observation of high temperature plasma of solar corona by TESIS/CORONAS-PHOTON and XRT/Hinode.
Abstract Author(s): Reva A.A (1), Kuzin S.V. (1), Bogachev S.A. (1), Shestov S.V. (1)
Institution(s): (1) Lebedev Physical Institute of the Russian Academy of Sciences
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 56 (Digital Poster Display)

TESIS is a space-borne complex of instrumentation created for investigation of solar corona. TESIS was launched aboard CORONAS-PHOTON satellite which was operating on near-Earth orbit since March 2009 till November 2009. Two TESIS channels—monochromatic MgXII 8.42 Å and narrow-band FeXX 132 Å were detecting high temperature plasma with T > 5 MK, which is close to temperature bands of some Hinode channels. At the same time TESIS Mg XII channel is monochromatic and does not register emission of plasma with temperature less than 5 MK. That is why Mg XII channel is an excellent marker for the region where hot plasma really exists. Different temperature response of TESIS and XRT telescopes allows to perform more precise plasma temperature diagnostics.In 2009 CORONAS-PHOTON and Hinode both operated on near-Earth orbit. In present work we analyze an active region, which was observed simultaneously by XRT and TESIS. This active region was observed from May 29 till June 10, 2009. We build temperature maps of active region with XRT data, and compare them with Mg XII data about high temperature plasma. Surprisingly we found no hot plasma (T>5 MK) on XRT temperature maps, but there was strong signal in Mg XII channel. That means that additional combined XRT-TESIS analyze is required for more accurate high temperature diagnostics.

A. Takeda: Elemental abundances, as a new source of uncertainty of the Hinode/XRT filter-ratio temperatures and emission measures of coronal structures.
Abstract Author(s): Takeda, A. (1), Kobelski, A. (1), McKenzie, D. (1), Yoshimura, K. (1)
Institution(s): (1) Montana State University
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 57

In the current standard Hinode/XRT analysis software, the filter-ratiotemperatures and emission measures are calculated from the XRT temperature response that assumes the 'coronal' abundances proposed by Feldman et al. (1992). These elemental abundances are characterized by an enhancementof the elements with low first ionization potential(FIP) by a factor of ~4 relative to their photospheric values. However, their study was based on the XUV spectrum formed less than 1 MK and thus our knowledge of coronal abundances over 1 MK is still insufficient.In view of these uncertainties, we calculated the XRT temperature response assuming two alternative sets of abundances, i.e., photospheric abundances(Grevesse and Sauval, 1998) and the 'hybrid' abundances (Fludra and Schmelz, 1999) with use of CHIANTI atomic database version 6.01. We found two fundamental effects: Firstly, that the new response functions with photospheric and hybrid abundances have lower peak counts (~30% and~60%, respectively) according to the reduced abundances of the low FIP elements, compared with the original response with the 'coronal' abundances. Secondly, the filter ratios with the photospheric and hybrid abundances tend to yield lower temperatures (~30% and ~15%, respectively in significant cases) than the coronal abundances. The emission measures derived for a givenfilter ratio are generally higher with the photospheric(~300%) and hybrid (~170%) abundances than with the coronal abundances, reflecting the reduced amplitude of the response functions with the former two abundances.We evaluated the significance of these differences, by comparing them with the uncertainty of the temperatures and emission measures derived from the observational data of active region (AR10923). The results obtained from the careful estimate of the uncertainty due to photon noise (statistical error) and the photometric (systematic) errors are presented.

J. Terradas: Transverse kink oscillations in threads observed with Hinode
Abstract Author(s): Terradas, J. (1)
Institution(s): (1) Universitat de les Illes Balears, E-07122 Palma de Mallorca, Spain
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 58

Hinode observations show ubiquitous transverse oscillations in flowing threads. The combination of waves and flow leads to a rich variety of effects that can help to have a better understanding of the nature of threads. In this work we use the magnetohydrodynamic (MHD) equations to analyze the effects of flow on transverse kink waves in the linear and nonlinear regime. We discuss how the periods and damping rates of kink waves are modified by the presence of flows. We also show that for large amplitude MHD kink oscillations nonlinearities might induce instabilities of Kelvin-Helmholtz type at the thread boundaries. We discuss the implications of the results respect to Hinode observations of transverse kink oscillations.

S. Terzo: Temperature Diagnostics of a solar active region using a Single-filter observation of Hinode/XRT
Abstract Author(s): Terzo S. (1), Reale, F. (1).
Institution(s): (1) INAF - Astronomical Observatory of Palermo
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 59

Spectroscopic observations are best-suited to obtain temperature information in the solar corona. Broad-band X-ray observations can provide limited temperature diagnostics through filter ratios. A high cadence observation of an active region made with a single Hinode/XRT filter allows us to use an alternative approach: we measure the time fluctuations of the pixel count rate and use the variance as temperature proxy. We show preliminary results and discuss limitations.

Z. Tian: A new model of TSI based on solar furface magnetic energy
Abstract Author(s): Tian, Z. (1)
Institution(s): (1) Beijing Normal University
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 60 (Digital Poster Display)

Several models of TSI bave been made based on some solar parameters, such as sunspot area,sunspot number,magnetic. Here presente a new method of reconstructing TSI based on solar surface magnetic engery.In the view of engery, we will analyse TSI.

R. Walsh: Explaining observed red and blue-shifts using multi-stranded coronal loops
Abstract Author(s): Walsh, R. W. (1), Regnier, S. (1), Pearson, J. (1)
Institution(s): (1) University of Central Lancashire
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 61 (Digital Poster Display)

Magnetic plasma loops have been termed the building blocks of the solar atmosphere. However, it must be recognised that if the range of loop structures we can observe do consist of many ''sub-resolution'' elements, then current one-dimensional hydrodynamic models are really only applicable to an individual plasma element or strand. Thus a loop should be viewed is an amalgamation of these strands. They could operate in thermal isolation from one another with a wide range of temperatures occurring across the structural elements. This scenario could occur when the energy release mechanism consists of localised, discrete bursts of energy that are due to small scale reconnection sites within the coronal magnetic field- the nanoflare coronal heating mechanism. These energy bursts occur in a time-dependent manner, distributed along the loop/strand length, giving a heating function that depends on space and time.An important observational discovery with the Hinode/EIS spectrometer is the existence of red and blue-shifts in coronal loops depending on the location of the footpoints (inner or outer parts of the active region), and the temperature of the emission line in which the Doppler shifts are measured. Based on the multi-stranded model developed by Sarkar and Walsh (2008, ApJ, 683, 516), we show that red and blue-shifts exist in different simulated Hinode/EIS passbands: cooler lines (Si VII) being dominated by red-shifts, whilst hotter lines (FeXV) are a combination of both. Characteristic Doppler shifts generated fit well with observed values.

P. Young: Plasma flows in active region fan loops
Abstract Author(s): Young, P.R. (1), O'Dwyer, B. (2), Mason, H.E. (2)
Institution(s): (1) George Mason University, (2) University of Cambridge, UK
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 62

EIS is the first coronal spectrometer to allow plasma flows in coronal loops to be tracked from the transition region into the corona. Results for an isolated fan loop structure will be presented showing that redshifts (downflows) of 15-20 km/s are found for temperatures up to 0.8 MK, but an abrupt change to a rest velocity is found for temperatures of 1.0 MK and above. As the 0.8 MK and 1.0 MK plasmas spatially co-exist in the same locations in the loop, the results are interpreted in terms of two sets of loop strands, one of which is cool and downflowing, the other is hotter and at rest. The implications for models of fan loops are discussed.

L. Abbo: Signature of Alfvén waves energy deposition above polar coronal holes with Hinode/EIS
Abstract Author(s): Bemporad, A. (1), Abbo, L. (1)
Institution(s): (1) INAF-Osservatorio Astronomico di Torino, Pino Torinese (TO), 10025 - Italy
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 63

Between February 24-25, 2009, the EIS/Hinode spectrometer performed special 'sit & stare' observations above the South polar coronal hole continuously over more than 22 hours. Spectra were acquired with the 1'' slit placed off-limb, covering altitudes up to 0.48 solar radii (1.74e2 Mm), in order to study the non-thermal spectral line broadenings. We have analyzed spectral lines such as FeXII 186.88, FeXII 195.12, FeXIII 202.04, HeII 256.32, and CaXVII 192.81, observed with good statistics up to higher altitudes. Results show that the FWHM of Fe XII 195.12 line increases up to about 0.16 solar radii, then decreases higher up. EIS stray light has been estimated and removed and from the observed line intensities and line profile widths we have derived electron density and non-thermal velocity profiles. The analysis suggests significant energy deposition by Alfven waves in a polar coronal hole above 0.16 solar radii, by assuming conservation of the wave energy flux along magnetic flux tubes. We also present first preliminary results from a further EIS off-limb study recently performed in coordination with SOHO/UVCS, including more EIS spectral lines.

E. Dzifcakova: X-ray and EUV filter responses and AR emission model for the non-thermal kappa-distributions
Abstract Author(s): Dzifcakova, E. (1), Dudik, J. (2,1), Karlicky, M. (1)
Institution(s): (1) Astronomical Institute of the Academy of Sciences of the Czech Republic, Fricova 298, 251 65 Ondrejov, Czech Republic, (2) DAPEM, Faculty of Mathematics, Physics and Informatics, Comenius University, Mlynska Dolina F2, 842 48 Bratislava, Slovak Republic
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 64 (Digital Poster Display)

The XRT and AIA filter responses to emission for the non-thermal electron with enhanced number of the particles in the high-energy tail (kappa-distributions) were calculated. Generally, the filter responses for the kappa-distributions are wider and shifted to higher temperatures. This behavior can affect temperature diagnostic. The effect of the non-thermal kappa-distributions on the resulting forward models of active region emission was analyzed. We have shown that their influence is small except for the extreme non-thermal cases.

E. Dzifcakova: Temperature diagnostic of an Active Region brightening observed by XRT
Abstract Author(s): Dudik, J. (1,2), Reeves, K. (3), Schmieder, B. (4), Dzifcakova, E. (2), and Golub, L. (3)
Institution(s): (1) DAPEM, Faculty of Mathematics, Physics and Informatics, Comenius University, Mlynska Dolina F2, 842 48 Bratislava, Slovak Republic, (2) Astronomical Institute of the Academy of Sciences of the Czech Republic, Fricova 298, 251 65 Ondrejov, Czech Republic, (3) Harvard-Smithsonian Center for Astrophysics, 60 Garden St. MS 58, Cambridge, MA 02138, USA, (4) LESIA, Observatoire de Paris, 5 Place Jules Janssen, 921 90 Meudon, France
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 65 (Digital Poster Display)

We analyze the temperature distribution of the active region observed by HINODE/XRT. The active region shows several loop brightenings in the active region core. The temperature structure is derived using three different methods: a single filter-ratio, Combined Improved Filter Ratio (CIFR) and a hardness-to-softness ratio utilizing five filters. Although the temperature distributions are similar, there can be rather large errors in individual pixels. The last method offers best option for minimalizing the S/N ratio and constrains the higher temperatures in brightening to less than 5 MK. The diagnosed temperatures are compared to the results of DEM analysis, which also shows relative absence of plasma with higher T.

S. Farid: Thermal Evolution of a Coronal Bright Point
Abstract Author(s): Farid, S. (1), Mulu-Moore, F. (2), Winebarger, A. (2), Cirtian, J. (2), Saar, S. (1)
Institution(s): (1) Harvard-Smithsonian Center for Astrophysics, Cambridge,Ma (2) NASA-Marshall Space Flight Center Hunstville, Al
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 66

oronal bright points (BPs) appear as small, compact, and relatively cool groups of short loops visible in Xray and EUV images. They are usually accompanied by magnetic bipoles and are often associated with jets, particularly when in coronal holes. BPs have been observed since Skylab, however many questions about their origin, evolution, and variation remain. We have recently demonstrated that joint observations from HINODE/XRT and SDO/AIA can constrain the differential emission measure (DEM) of BPs. Now we examine the thermal and morphological evolution of a long-lived bright point located near the boundary of an on-disk coronal hole. We compute the DEM over the lifetime of the BP and examine changes in the associated magnetic bipole. We explore its thermal evolution from emergence, core brightening, the discharge of a small jet, decay and re-emergence.

B. Fleck: High-frequency Acoustic Waves in the Solar Atmosphere: Comparing Hinode/SP Observations with Numerical Simulations
Abstract Author(s): Fleck, B. (1), Straus, T. (2), Severino, G. (2)
Institution(s): (1) ESA, (2) INAF/OAC
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 67

Even 60 years after the pioneering papers by Schwarzschild and Biermann, the role of high-frequency acoustic waves for the energy balance of the solar atmosphere is still intensely debated. Here we investigate the signatures of high-frequency acoustic waves in Hinode/SP observations and compare them to those found in line spectra synthesized from high-resolution 3D radiation-hydrodynamics simulations. The Hinode/SP time series extends over 4 hours, with a cadence of 16 s and a spatial resolution of 0.16 arcsec/pixel. The numerical simulation of the Sun’s surface layers was computed with the radiation hydrodynamics code CO5BOLD. The simulated domain is defined by a fixed 3D Cartesian grid with 400 x 400 x 300 cells, each of size 14 km x 14 km x 7.5 km. The simulation thus covers a horizontal area of 5.6 x 5.6 Mm. Periodic lateral boundaries are used. The transmitting upper boundary is located at a height of approximately 900 km above the visible solar surface, while the open lower boundary lies 1.4 Mm below the surface. The part of the simulation that we used has completely relaxed and covers approximately two hours of solar time with snapshots saved every 10 s. A line-synthesis code, based on the assumption of local thermodynamic equilibrium (LTE), was then fed with the physical parameters of the simulation to produce synthetic, two-dimensional spectra of the photospheric lines of Fe 6301/6302 (Hinode/SP), Fe 6173 (SDO/ HMI), and Ni 6768 (SOHO/MDI). The resulting Doppler velocity time series are analyzed using Fourier techniques and compared to the observed Hinode/SP spectra.

V. Hansteen: The mass balance between the chromsphere and corona
Abstract Author(s): Hansteen, V (1), Guerreiro, N. (1), Gudiksen, B. (1)
Institution(s): (1) Insititute of theoretical astronphysics, University of Oslo
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 68

In general and on average observations of transition region emission lines reveal the presence of redshifts in lines formed from the top of the chromosphere up to temperatures of about 250000 K and blueshifts for temperatures greater than that. However, it is doubtful that the apparent large downward flows in the lower transition region represent a net flow emptying of the corona, so some mechanism must be responsible for maintaining the mass balance between the lower atmospheric layers and the corona. We use a 3D-MHD code, Bifrost, which includes non-grey, non-LTE radiative transfer in the photosphere and lower chromosphere, optically and effectively thin radiation in the upper chromosphere, transition region and corona, conduction along the magnetic field lines andheating through the ohmic dissipation of tangled magnetic field lines to simulate the solar atmosphere. The motion of material originally in the transition region is tracked both as a minority fluid and in the form of corks. We report on the coronal mass balance and the mass flow mechanism for conditions perhaps typical of the quiet sun.

V. Hansteen: Simulated vs observed emission measures of the solar corona
Abstract Author(s): Hansteen, V. (1), Testa, P. (2), De Pontieu, B. (3), Martinez, J. (1,3), Carlsson, M. (1), Gudiksen, B. (1)
Institution(s): (1) Institute of theoretical astrophysics, University of Oslo, (2) Harvard Smithsonian Center for Astrophysics, Cambridge MA (3) Lockheed Martin Solar and Astrophysics Laboratory, Palo Alto CA
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 69

The Extreme ultraviolet Imaging Spectrograph (EIS) onboard Hinode and the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) provide a wealth of information on the physical conditions in the solar corona. These observational constraints are used to help determine the heating mechanisms driving the dynamics and energetics of coronal loops. In this poster we carry out detailed comparisons between differential emission measures, densities and temperatures of observed coronal plasma with those produced by numerical models of coronal loops. The simulations are made using a 3d-MHD code, Bifrost, and span a numerical domain from the convection zone into the corona, include radiative losses from optically thick and thin lines in the chromosphere and corona, as well as thermal conduction. These simulations self-consistently produce a hot corona through the ohmic dissipation of tangled magnetic field lines. We will explore the limitations of the diagnostics and their implications, as a function of the plasma parameters.

Y. Kato: Propagation of Slow-Modes through the Transition Region in Network Magnetic Elements
Abstract Author(s): Kato, Y. (1), Carlsson, M. (2), Hansteen, V. (2), Steiner, O. (3)
Institution(s): (1) NAOJ, Tokyo, Japan, (2) ITA, University of Oslo, Oslo, Norway, (3) KIS, Freiburg, Germany
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 70 (Digital Poster Display)

We investigate the propagation of longitudinal slow modes which are excited within magnetic flux concentrations by convective downdrafts in the immediate surroundings of the magnetic element, using radiation magnetohydrodynamic (RMHD) simulations of the solar atmosphere comprising the layers from the upper convection zone to the lower corona. We name this the ''magnetic pumping process''. We find that the generated slow modes travel along the magnetic flux concentration in the upward direction, develop into a shock wave in chromospheric heights, and propagate further through the transition region. In the course of propagation through the transition region, a small fraction of the longitudinal slow mode is converted into a transverse wave mode. We report on how much energy is deposited by propagating shock waves through the transition region and we discuss on the dissipation process above the photosphere within the magnetic flux concentration.

A. Kuwahata: Observation of Magnetic Fluctuations with Ion Cyclotron Frequency Range during Reconnection in Plasma Merging Experiment
Abstract Author(s): Kuwahata, A. (1), Boxin, G. (1), Ito, T. (1), Oka, H. (1), Tanabe, H. (1), Ito, S. (1), Inomoto, M. (1), Ono, Y. (1)
Institution(s): (1) The University of Tokyo
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 71

Magnetic reconnection has the deep relationship to solar activities, such as solar flares, solar winds and CMEs. Recent laboratory experiments have demonstrated that plasmoid ejection, waves and current sheet instabilities are important for the fast reconnection and resulting plasma heating and/or particle acceleration. In this paper, low frequency magnetic fluctuations generated by driven magnetic reconnection have been investigated in the TS-3 torus plasma merging device. Large amplitude magnetic fluctuations with ion cyclotron frequency range were observed inside the current sheet during magnetic reconnection in plasma merging experiment with a guide field: the guide field at the X-point Bx of 65mT is comparable to the reconnecting magnetic field B// in this experiment. The frequency spectrum of the magnetic fluctuation has clear peak at 2MHz, which is about twice as high as the local ion cyclotron frequency at the X point. The magnetic field variation due to the fluctuation is larger than 20% of the reconnecting magnetic field. In the initial phase of reconnection, the fluctuation brought a magnetic field modification like an island structure. Then the fluctuation was observed to travel radially to the downstream when the current sheet half width was compressed to ion gyroradius or inertia length. The magnetic fluctuation was observed to propagate radially across the reconnected magnetic field with velocity of about 70km/s, which is comparable to the local Alfven velocity, and strongly damped at the downstream region. Large electric field fluctuations and the enhancement of reconnection rate were also observed. These results suggest that the fast magnetic reconnection is provided by non-steady current sheet modification.

W. Liu: Heating of Flare Foops During a Two-ribbon Flare on 2005 May 13
Abstract Author(s): Liu, W. J. (1), Qiu, J. (1), Longcope, D. W. (1)
Institution(s): (1) Montana State University, Bozeman
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 72 (Digital Poster Display)

Many eruptive flares exhibit two extended ribbons in the lower-atmosphere outlining the feet of the post-flare coronal arcade. High-cadence and high-resolution UV observations by TRACE reveal that the flare ribbon consists of small patches sequentially brightened along the ribbon, suggesting that reconnection takes place sequentially forming individual post-flare loops along the arcade, as often seen in coronal observations in the EUV wavelengths. These reconnection events and formation of new loops continue well into the decay phase. Our recent study (Qiu et al. 2010) further shows that the spatially resolved UV brightness at the foot-points of individual loops grows rapidly on timescales of a few minutes, followed by a long decay on timescales of more than 10 minutes. The rapid rise of UV radiation is correlated with the hard Xray light curve during the impulsive phase, hence is most likely a direct response of instantaneous heating in the reconnection formed flux tubes. In this study, we utilize the spatially resolved UV brightness time profiles to reconstruct instantaneous heating functions of individual flux tubes, and compute evolution of each flux tube using the EBTEL model (Klimchuk et al. 2008). The temperature and density of these flux tubes are then used to calculate light curves in other energy bands and compare favorably with observations by RHESSI and GOES. This study presents the first effort to constrain heating functions of flare loops directly using all available observables, and provides a powerful way to examine physics of heating discrete flux tubes formed by reconnection events throughout the flare.

D. Nandi: Coronal Heating and Magnetic Properties of Solar Active Regions: Confronting the Relationship with High Resolution Observations from Hinode SOT and XRT
Abstract Author(s): Nandy, D. (1), Hazra, S. (1), Ravindra, B. (2)
Institution(s): (1) Indian Institute of Science Education and Research, Kolkata, India, (2) Indian Institute of Astrophysics, Bangalore, India
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 73

The brightest regions of the Sun's corona are associated with active regions indicating that the magnetic properties of active regions play a crucial role in coronal heating. Exploring the relationship between coronal X-ray flux and active region properties can therefore illuminate the mechanisms responsible for the heating of stellar coronae. While it is thought that active region non-potentiality and currents should influence coronal heating, studies from the Yohkoh era have not found any evidence in support of this. We revisit this relationship between active region magnetic properties and coronal heating by comparing co-spatiotemporal coronal X-ray and photospheric vector magnetic field observations from the XRT and SOT instruments, respectively, onboard the Hinode satellite. Here, we present a summary of our main findings.

K. Reeves: Thermal properties and evolution of a coronal cavity as observed by the X-Ray Telescope on Hinode
Abstract Author(s): Reeves, K. K. (1), Gibson, S. E. (2), Kucera, T. A. (3), Hudson, H. S. (4), Kano, R. (5)
Institution(s): (1) Harvard-Smithsonian Center for Astrophysics (2) HAO/NCAR (3) NASA GSFC (4) SSL, U. C. Berkeley, (5) National Astronomical Observatory of Japan
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 74

Coronal cavities are voids in coronal emission often observed above high latitude filament channels. Sometimes, these cavities have areas of bright X-ray emission in their centers (i.e. Hudson et al 1999). In this study, we use data from the X-ray Telescope (XRT) on Hinode to examine the thermal emission properties of a cavity observed during July 2008 that contains bright X-ray emission in its center. Using ratios of XRT filters, we find evidence for elevated temperatures in the cavity center. The area of elevated temperature evolves from a ring-shaped structure at the beginning of the observation, to an elongated structure two days later, finally appearing as a compact round source four days after the initial observation. We use a morphological model to fit the cavity emission, and find that a uniform structure running through the cavity does not fit the observations well. Instead, the observations are reproduced by modeling several short cavity "cores" with different parameters on different days. These changing core parameters may be due to some observed activity heating different parts of the cavity core at different times. We also find that core temperatures of 1.75 MK, 1.7 MK and 2.25 MK (for 19 July, 21 July and 23 July, respectively) in the model lead to structures that are consistent with the data, and that line-of-sight effects serve to lower the effective temperature derived from the filter ratio.

Y. Suematsu: Study of Small-Scale Chromospheric Plasmoid Ejections with Improved Hinode Ca II H Filtergrams
Abstract Author(s): Suematsu, Y. (1)
Institution(s): (1) National Astronomical Observatory of Japan
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 75 (Digital Poster Display)

We present observations of intermittent ejections of small-scale blob-like chromospheric structures which may indicate magnetic reconnection process between cool chromosphere and hot coronal magnetized layers. The observations were taken with Hinode SOT/BFI Ca II H filtergrams at an active region when a large sunspot region was just on the west limb. The activity of the blob ejections was seen near an apex of low-lying chromospheric loop systems which are likely to connect the sunspot and its outer opposite polarity regions. The blob ejections were dominantly directed to the sunspot like the motion of inverse Evershed flows but also directed away from the sunspot, sometimes showing bi-directional flows. The size of blobs ranges from 0.2 to 1 arcsec and their apparent velocities exceed 50 km/sec. To derive detailed structures and motion of the blob ejections, we improved the filtergrams by applying a kind of phase diversity image restoration method. We discuss the observational results with a context of magnetic reconnection models.

H. Tanabe: Laboratory Experiment on Plasma Heating During Magnetic Reconnection in Torus Plasma Merging Device TS-3 and TS-4
Abstract Author(s): Tanabe, H. (1), Kuwahata, A. (1), Oka, H. (1), Annoura, M. (1), You, S. (2), Inomoto, M. (1), Ono, Y. (1)
Institution(s): (1) University of Tokyo, (2) University Washington
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 76

We have investigated the energy dissipation mechanism of magnetic reconnection, a key physics of violent plasma acceleration and heating in solar flare, by use of torus plasma merging experiment on TS-3 and TS-4. Making use of the accessibility to the diffusion region in laboratory experiment, we studied the heating mechanism of the magnetic self-organization process by probe measurements and ion Doppler optical diagnostics. Line-integrated effect for the passive ion Doppler measurement is removed by tomographic reconstruction technique ^[1]; we can discuss local heating mechanism for ion and electron both. The measured results clearly show that ion is heated at the down stream area of outflow jet and electron temperature profile has a peak at the current sheet region, indicating that ion is mainly heated by the damping energy of outflow jet by viscosity and shock, while electron is heated by resistive current sheet dissipation. The ion heating efficiency depend on the varied guide toroidal field Bt. The maximum ion temperature T_i~140eV is obtained in the counter helicity merging spheromaks with no guide field B_t, T_i~100eV in the co-helicity merging spheromaks with B_t~B_p (reconnection field) and T_i~50eV in the tokamak merging with B_t>B_p. The tokamak merging experiment with varied guide field Bt revealed that the ion temperature increment ΔT_i after reconnection decreases inversely with the guide field B_t but that ΔT_i tends to be saturated in high guide field regime.
^[1] H. Tanabe., et al., Rev. Sci. Instrum., submitted (2011)

T. Tarbell: The role of the magnetic field in the formation of chromospheric spicules
Abstract Author(s): Tarbell, T. (1), de la Cruz Rodriguez, J. (1), De Pontieu, B. (1), Rouppe van der Voort, L. (1), Sekse, D. (1), Pereira, T. (1), Martinez-Sykora, J. (1), Hansteen, V. (1), McIntosh, S. (1), Carlsson, M. (1), Sainz-Dalda, A. (1)
Institution(s): (1) LMSAL, (2) UiO, (3) HAO, (4) NASA Ames, (5) Stanford
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 77 (Digital Poster Display)

Fast moving, so-called "type II spicules" have recently been implicated in providing the corona with hot plasma. However, we do not understand how they form, and what role the magnetic field plays in driving these supersonic jets into the corona. The recent discovery of so-called rapid blue shifted events (RBEs), the disk counterpart of type II spicules, allows us to study in detail the magnetic field configuration at the root of these jets. We use a one hour long timeseries of H-alpha 6563Å and Ca II 8542Å images obtained with the CRISP instrument at the Swedish Solar Telescope (SST) in La Palma, Spain to identify the rapid chromospheric upflows. To determine whether the photospheric field configuration at the roots of spicules can provide insight into the formation mechanism of spicules, we analyze the vector magnetic field at the spicule roots using data from the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO), as well as fast raster scans from the SpectroPolarimeter (SP) onboard Hinode. We also use spectropolarimetric observations in Ca II 8542Å to investigate how the chromospheric magnetic field is related to the formation of spicules, and more generally heating in the upper chromosphere. We compare our observations with synthetic observations from 3D radiative MHD simulations using the Bifrost code.

H. Tian: High-speed Outflows on Plume-like Structures of the Quiet Sun and Coronal Holes
Abstract Author(s): Tian, H. (1), McIntosh, S. W. (1), Habbal, S. R. (1), He, J. (1)
Institution(s): (1) High Altitude Observatory, National Center for Atmospheric Research
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 78 (Digital Poster Display)

Observations from the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) reveal ubiquitous episodic outflows (jets) with an average speed around 120 km s⁻¹ at temperatures often exceeding a million degree in plume-like structures, rooted in magnetized regions of the quiet solar atmosphere. These outflows are not restricted to the well-known plumes visible in polar coronal holes, but are also present in plume-like structures originating from equatorial coronal holes and quiet-Sun regions. Outflows are also visible in the “inter-plume” regions throughout the atmosphere. Furthermore, the structures traced out by these flows in both plume and inter-plume regions continually exhibit transverse (Alfv ́enic) motion. Our finding suggests that high- speed outflows originate mainly from the magnetic network of the quiet Sun and coronal holes, and that the plume flows observed are highlighted by the denser plasma contained therein. These outflows might be an efficient means to provide heated mass into the corona and serve as an important source of mass supply to the solar wind. We demonstrate that the quiet-Sun plume flows can sometimes significantly contaminate the spectroscopic observations of the adjacent coronal holes - greatly affecting the Doppler shifts observed, thus potentially impacting significant investigations of such regions.

S. Tsuneta: Evidence of magnetic heating of chromosphere
Abstract Author(s): Tsuneta, S. (1), Ueda, K. (1), Reardon, K. (1), Cauzzi, G. (2), Ishikawa, R. (1)
Institution(s): (1) NAOJ, (2) Arcetri
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 79 (Digital Poster Display)

Cauzzi et al (2009) demonstrated with IBIS that the width of the H-alpha line may be a very good measure of chromospheric temperature. Following this paper, we performed high-cadence, high-resolution limb (and disk-center) observations at two wavelengths (blue and red) of the H-alpha line with Hinode. The limb observations allow us to better see the vertical structure of the chromospheres, but are difficult to obtain with ground-based telescopes due to the limitations of adaptive optics.
The temperature maps thus obtained appear quite different from usual high-resolution H-alpha maps (Cauzzi et al). We present remarkable movies of the near-limb (and disk center) chromospheric temperature structures. While the inter-network regions are filled with acoustic-shock signatures with approximately 3 min period, the network regions have a different appearance than that shown by Cauzzi et al.
Instead, we see heated, canopy-like inclined fine-threads around the network magnetic concentrations. This suggests the existence of a heating mechanism such as magnetic reconnection in the ubiquitous emerging magnetic fields in and around the chromospheric network regions. It is quite interesting to evaluate this phenomena in terms of the view point recently proposed by De Pontieu et al. (2009, 2011).

T. Wang: Slow-mode oscillations of hot coronal loops excited at flaring footpoints
Abstract Author(s): Wang, T. (1,2), Liu, W. (3), Ofman, L. (1,2), and Davila, J. M. (2)
Institution(s): (1) Catholic University of America, Washington, DC, USA, (2) NASA's Goddard Space Flight Center, Greenbelt, MD, USA, (3) Lockheed Martin Solar and Astrophysics Laboratory, CA, USA.
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 80 (Digital Poster Display)

A large number of strongly damped oscillations in hot coronal loopshave been observed by SOHO/SUMER in the past decade in Doppler shifts of flaring (>6 MK) lines (Fe XIX and Fe XXI). These oscillations with periods on the order of 10-30 min were interpretedas fundamental standing slow modes. They often manifestfeatures such as recurrence and association with a flow (100-300 km/s) pulse preceding to the oscillation, which suggests that they are likely driven by microflares at the footpoints.With coordinated RHESSI observations, we have found a dozen such events supporting this conjecture. A typical event is presetned here. By analyzing RHESSI hard X-ray and GOES/SXI soft X-ray emissions as well asSUMER Doppler shifts, we identify the flare that triggers the loop oscillations.
From RHESSI spectra, we measure physical parameterssuch as temperature, emission measure, and thermal/non-thermal energy contents as functions of time. We discuss the wave excitation mechanism based on these observations. Our results provide important observationalconstraints that can be used for improving theoretical models ofmagnetosonic wave excitation, and for coronal seismology.

H. Warren: Modeling Slow Speed Solar Wind Streams
Abstract Author(s): Warren, H. (1), Mariska, J. (1)
Institution(s): (1) NRL
Session: Energy transport and dissipation through the solar atmosphere and into the heliosphere
Poster #: 81 (Digital Poster Display)

One of the most significant discoveries with the EIS instrument on Hinode is the detection of persistent, high-speed outflows from large areas at the periphery of many active regions. Recent work has determined the properties of these outflows and provided strong evidence that they connect to the heliosphere and contribute to the slow speed solar wind. One curious property of the active region outflows is that they are easily measured in emission lines from Fe XII and Fe XIII, indicating temperatures well above 1 MK. The outflowing plasma in polar coronal holes, in contrast, is characterized by much lower temperatures. Previous work on the hydrodynamics of open flux tubes has emphasized the importance of the energy deposition at low heights for determining the asymptotic properties of the solar wind. Strong heating near the base leads to slower wind speeds and higher temperatures and densities. Here we discuss the application of 1D hydrodynamic models to EIS observations of the active region outflows and the implication of these results to the properties of the slow speed solar wind.

P. Heinzel: Time series of synthetic spectra from prominence oscillations
Abstract Author(s): Heinzel, P. (1), Ballester, J. L. (1), Zapior, M. (1), Oliver, R. (1)
Institution(s): (1) Astronomical Institute, Academy of Sciences
Session: Instabilities, Transients and Eruptions
Poster #: 82

MHD models of prominence oscillations have been constructed in the past forvarious modes of oscillations. However, in order to constrain these models against existing observations, one needs time series of synthetic spectra of the oscillating prominence. Here we perform, for the first time, a full non-LTE radiative-transfer synthesis of time-dependent hydrogen and calcium spectra emergent from model prominences with oscillations. For this exploratory work we use a rather simple 1D slab model with various modes of oscillations, illuminated by the incident solar radiation. We solve coupled equations of radiative transfer and statistical equilibrium, in presence of internal velocity fields, and obtain theoretical temporal variations of the line intensities, widths and Doppler shifts or line asymmetries. These can be directly compared with observations having high spectral resolution. Finally we discuss limitations of our approach and future prospects.

Y. Li: Interactions and Eruptions of Two Filaments Observed by Hinode, SOHO, and STEREO
Abstract Author(s): Y. Li and M. D. Ding
Institution(s): Montana State University
Session: Instabilities, Transients and Eruptions
Poster #: 83

We investigate the interactions between two filaments and the following eruptions from different angles of view, observed by Hinode, the Solar and Heliospheric Observatory (SOHO), and the Solar Terrestrial Relations Observatory (STEREO). In the event, the two filaments rose high, interacted with each other, and finally produced ejections along two different paths. We measure the bulk-flow velocity using spectroscopic data. There appeared significant outflows with a speed of hundreds of km/s during the ejections, and also some downflows of about tens of km/s at the edge of the eruption region during the last stage. The erupting material contained plasmas with a wide temperature range of 10⁴-10⁶ K.

D. McKenzie: Distribution of the Sizes and Fluxes Produced in Patchy Reconnection
Abstract Author(s): McKenzie, D. E. (1), Savage, S. L. (2)
Institution(s): (1) MSU, (2) NASA-GSFC
Session: Instabilities, Transients and Eruptions
Poster #: 84

Supra-arcade downflows (SADs) are downward-moving features observed in the hot, low-density region above posteruption flare arcades. They are believed to be created by patchy reconnection in the post-CME current sheet, and so their characteristics provide information about the process of their creation. For example, the "fractal current sheet" scenario proposed in the literature may be expected to yield a power-law distribution of sizes and/or fluxes. We examine 120 cross-sectional areas and magnetic flux estimates from low-resolution observations of SADs, and find that (1) the areas are consistent with a log-normal distribution, and (2) the fluxes are consistent with both a log-normal and an exponential distribution. Neither set of measurements is compatible with a power-law distribution, and so the data do not appear to support a fractal process for SAD creation. Because these measurements are derived from low-resolution (pre-Hinode) observations, we anticipate that improved flare images with higher resolution will provide a better probe of the sizes and fluxes that are characteristic of patchy reconnection. We will show that with the recently increasing solar activity, Hinode/XRT and SDO/AIA are optimally positioned for advancing this type of study.

N. Murphy: Asymmetric Magnetic Reconnection in Coronal Mass Ejection Current Sheets
Abstract Author(s): Murphy, N. A. (1), Miralles, M. P. (1), Pope, C. L. (1,2), Raymond, J. C. (1), Reeves, K. K. (1), Seaton, D. B. (3), and Webb, D. F. (4)
Institution(s): (1) Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA, (2) Elmhurt College, Elmhurst, IL, USA, (3) Royal Observatory of Belgium, Brussels, Belgium, (4) Boston College, Boston, MA, USA
Session: Instabilities, Transients and Eruptions
Poster #: 85

Flux rope models of coronal mass ejections (CMEs) predict the formation of an elongated current sheet in the wake behind the rising plasmoid. Features identified as current sheets have been seen during a number of eruptions observed by instruments such as XRT, EIS, LASCO, and AIA. These current sheets frequently drift or tilt with time at rates of up to 20 degrees/day, much faster than could be accounted for by solar rotation. This drift could be caused by different parts of the current sheet actively reconnecting at different times, the rising plasmoid propagating at an angle and pulling the current sheet along with it, or asymmetry from the reconnection process itself. We investigate the effects of line-tied asymmetric reconnection in CME current sheets using resistive magnetohydrodynamic simulations. The X-line drifts away from the Sun and toward the upstream region with the stronger magnetic field. Because the X-line is located near the low-altitude base of the current sheet, most of the energy is directed upward toward the rising plasmoid rather than toward the lower boundary representing the photosphere. The rate of drift predicted from the simulations is comparable to the observed rate of current sheet tilting during the Cartwheel CME. The post-flare loops show a characteristic skewing that is observable by XRT.

S. Pucci: X-ray jets and Bright Points: evidence for sympathetic activity
Abstract Author(s): Pucci, S. (1), Poletto, G. (2), Sterling, A.C. (3), Romoli, M. (4)
Institution(s): (1)Department of Physics and Astronomy, University of Firenze, Firenze, Italy, (2) NAF - Arcetri Astrophysical Observatory, Firenze, Italy, (3) Space Science office, VP 62, Marshall Space Flight Center, Huntsville, AL 35812, USA, (4) Department of Physics and Astronomy, University of Firenze, Firenze, Italy
Session: Instabilities, Transients and Eruptions
Poster #: 86 (Digital Poster Display)

We present in this work an analysis of X-ray Bright Points (BPs) and X-ray jets that occurred within the northern polar coronal hole, as observed by the Hinode X-Ray Telescope (XRT ) over two time intervals, each of about 20 hours during the period 2-4 Nov 2007. We performed a photometric analysis of the BPs observed within two selected subregions of the coronal hole and examined whether there is any correlation between the BPs intensity fluctuations and the occurrence of jets originating within the same area. Our results show: 1) The most important BP brightness fluctuations occur nearly simultaneously for different BPs, and 2) Jets are observed in close temporal association with these multiple-brightening events. We interpret these jet events in terms of magnetic connectivity changes that concurrently produce the BPs brightness fluctuations, surmising that magnetic interactions that produce both the BPs and jets in polar coronal holes are small-scale versions of active-region-scale phenomena whereby interacting bipoles trigger flares and eruptions.

A. Sterling: Hinode and SDO Observations of the Onset of a CME-Producing Eruption
Abstract Author(s): Sterling, A. (1), Moore, R. (1)
Institution(s): (1) NASA Marshall Space Flight Center
Session: Instabilities, Transients and Eruptions
Poster #: 87

We observe the onset dynamics and characteristics of a GOES mid-C-level,CME-producing eruption of 2011 June 1, using data from both SDO and Hinode. Hinode experienced satellite night prior to the peak of the event, but itobserved well the start of the eruption. The eruption itself was a complexaffair, with at least three peaks in the GOES soft X-ray intensity profile. Hinode/XRT and SDO/HMI data show that, near the time of the event's initiation,a strong "pre-flare" soft X-ray brightening occurred at the site of a strongisland of positive magnetic flux isolated in a sea of surrounding negativeflux. This positive flux island steadily declines by about a factor of two instrength over the eight hours prior to eruption, consistent with that fluxisland undergoing cancelation with surrounding field. Combined AIA and HMI datashow that following the initial preflare episode, a two-stage cascade oferuptions subsequently occurs along the main polarity inversion line of theerupting region, with this cascade contributing to the complexity of the GOESlight curve. A filament in one of the eruptions becomes intertwined withbrightly-emitting filament strands during the eruption, similar tocharacteristics we have seen in other events. In AIA 304 images we measuresteady pre-eruption flows at locations near the eruption of ~20-60 km/s, whileflows along the filament structures during eruption onset reach up to ~200km/s. Our observations suggest that flux cancelation near the isolated positiveisland triggered release of magnetic energy, leading to successivedestabilizations and eruptions of larger-scale magnetic structures.

R. Walsh: A new view of the structure, evolution and eruption of a polar crown cavity
Abstract Author(s): R. W. Walsh (1), S.Regnier (2), C.E. Alexander (3)
Institution(s): (1) University of Central Lancashire
Session: Instabilities, Transients and Eruptions
Poster #: 88

We report on the evolution of a negative curvature (U-shaped) polar crown cavity observed on 13th June 2010. Concentrating primarily on SDO/AIA data, we define the polar crown cavity as a density depletion sitting above denser polar crown filament plasma that is draining down the cavity by gravity. As part of the filament, plasma at different temperatures (ranging from 50,000 K to 0.6 MK) is observed co-located within the cavity dips, sustained by a competition between gravity and magnetic tension of the curved magnetic field. The evolution follows very closely the classical three-part ejection model of filament, cavity and outer shock front. In fact, the eruption of the cavity can be decomposed into two distinct phases; a slow rise phase (approximately 0.6 kms-1) followed by an acceleration phase (with mean speed 25 kms-1).Possible trigger mechanisms of the eruption, whether external (eg. nearby flaring) and/or internal (eg. kink instability, mass loading) will be presented to give a fuller three-dimensional view of the entire event. Note that the preliminary analysis of the cavity has been accepted for publication (Regnier, Walsh & Alexander, 2011, A & A, 533, L1).

T. Watanabe: High-Temperature & High-Speed Downflows in an Impulsive Flare of 2011 March 12
Abstract Author(s): Watanabe, T. (1), Hara, H. (1), Imada, S. (2), Watanabe, K. (2), Shimizu, T. (2)
Institution(s): (1) NAOJ, (2) ISAS/JAXA
Session: Instabilities, Transients and Eruptions
Poster #: 89

A new EIS study for flares (#390): HH_Flare_180x160_v2 enables a high-cadence raster scanning observation for an area of 180 arcsec x 160 arcsec, with 2 arcsec slit shifting E-W 5 arcsecs per exposure. The exposure time is set to 10 seconds, and the time cadence of raster scan is about 360 seconds. This study have caught an initial phase of a C9.6 flare occurred on March 12, 2011.
This flare was very impulsive, started at 17:19UT, and ended at 17:34UT in GOES soft X-ray light curves. RHESSI spectra and images drawn in the energy range of E < 25 keV showed thermal nature of the source, while a few small bursts in the 25 - 50 keV energy range revealed the precipitation sites of non-thermal electrons.
Fast downflows reaching + 200 km/sec at these footpoints were observed in the iron emission lines formed in lower temperatures than that of FeXVI, namely, log Te < 6.4. The line profile of the OVI line of the transition-region origin even showed downward moving plasma with a speed of + 150 km/sec.
The observing spectral windows for FeXIV density-sensitive line pairs did not cover their entirely redshifted line profiles, but the electron density of these fast-moving plasmas were managed to be estimated ne ~ 10¹⁰ cm^-3.
Comparing AIA and RHESSI images with EIS raster images, these high-speed downflows are considered to have close relationship with a saturated conduction front generated by thermal heating at the apices of the flaring loops reaching their foot-points.

K. Watanabe: Statistical Analyses of White-Light Flares observed by Hinode/SOT
Abstract Author(s): Watanabe, K. (1), Shimizu, T. (1), Masuda, S. (2), Ichimoto, K. (3)
Institution(s): (1) ISAS/JAXA, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa, Japan (2) STE Laboratory, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan (3) Kwasan/Hida Observatories, Kyoto University, Yamashina, Kyoto, Japan
Session: Instabilities, Transients and Eruptions
Poster #: 90

We have used Hinode flare catalog (http://st4a.stelab.nagoya-u.ac.jp/gemsis/hinode_flare/) to perform a statistical study of white-light flares. We found 11 white-light events by using G-band and continuum data of Hinode/SOT until now.
White-light flares are flares that show an enhancement in the visible continuum. White-light emissions are well correlated with HXR and radio emissions in time profile and emission location. So, there is some consensus that the origin of white-light emission is accelerated particles, in particular non-thermal elections.
Previously we analyzed one of the 11 white-light events on December 14th, 2006 in detail. In this event, a significant enhancement of white-light (G-band) emission was observed, and white-light and hard X-ray emissions were seen at almost the same location. We assume that the thick target model to calculate the power of accelerated electrons from the X-ray spectra, and we also assume that a blackbody to calculate the power of white-light emission. The power of white-light emission is well correlated with hard X-ray power which cutoff energy is 40keV (Watanabe et al., 2010).
Recent white-light events (e.g. X2.2 flare on 15 February 2011) were observed by using three continuum bands (Red, Green and Blue). From these data, we can determine precisely the temperature of the region where the white-light emissions were enhanced. Moreover, hard X-ray emissions were also observed by RHESSI.
In this talk, we present analysis results of recent white-light flares in detail and a statistical analysis of the SOT white-light events. We also discuss the flare parameters and review models to explain the observations in terms of particle acceleration.

K. Aoki: A High-Velocity Motion of Active Region Loops Triggered by a 2011 Feb 18 Flare
Abstract Author(s): Aoki, K. (1), Hara, H. (2)
Institution(s): (1) University of Tokyo, Tokyo, Japan, (2) National Astronomical Observatory of Japan, Tokyo, Japan
Session: Instabilities, Transients and Eruptions
Poster #: 91

We report a high-velocity plasma motion near the lop-top region of large-scale active-region loops after the occurrence of the M-class flare at the active region NOAA11158 on 2011 Feb 18. The motion was detected during the impulsive phase of the M-class flare by the Doppler-shift measurement in Fe XXIV at 192A with the Hinode EUV imaging spectrometer (EIS). In order to identify the high-velocity component from the temporal evolution of the coronal structures, we use high-cadence EUV images at 94 and 131A from Atmospheric Imaging Assembly (AIA) on Solar Dynamics Observatory (SDO). We have found that the Doppler velocity near the loop-top region reaches 200-400 km/s and the motion is also identified in the AIA EUV images. Before the appearance of the high-speed plasma, large-scale loops were heated to a flare temperature in association with the occurrence of the M-class flare. One of the loops that rose vertically at ~200 km/s interacted with other loop structures located above it. We discuss the possible mechanisms that are responsible for the high-velocity motion near the loop-top region from the detailed Doppler feature and the 3D coronal structures that are determined by the stereoscopic measurement from AIA 193A and STEREO-A 195A images.

T. Berger: The Rayleigh-Taylor Instability in Solar Prominences: a review of Hinode and SDO resuls
Abstract Author(s): Berger, T. (1)
Institution(s): (1) Lockheed Martin Solar and Astrophysics Laboratory
Session: Instabilities, Transients and Eruptions
Poster #: 92 (Digital Poster Display)

We review the discovery and analysis of the Rayleigh-Taylor (RT) instability in quiescent polar crown prominences. Discovered shortly after the Hinode launch by the SOT instrument, we have since analyzed these instabilities using all three Hinode instruments as well as the Solar Dynamics Observatory AIA instrument. We find that the instability is caused by the emergence of 1 MK plasma "bubbles" from the chromosphere below quiescent prominences. The buoyancy instability sets in at the interface between the hot under-dense bubbles and the cooler dense prominence plasma above. We speculate that these bubbles are caused by emerging twisted magnetic flux which is heated to coronal temperatures low in the atmosphere via reconnection with the surrounding coronal magnetic fields. Quiescent prominences and their associated coronal cavities can thus be seen as large-scale magneto-convection flow systems in which high temperature magnetic flux is buoyantly injected from below while the condensing return flow from the coronal cavity forms the cool downflows typical of quiescent prominences. We discuss the implications of this finding for understanding polar crown CMEs and eruptive events in general.

I. Hannah: Differential Emission Measures from the Regularized Inversion of SDO and Hinode data
Abstract Author(s): (1) Hannah, I. G., (1) Kontar, E. P., (1) Fletcher, L.
Institution(s): (1) University of Glasgow
Session: Instabilities, Transients and Eruptions
Poster #: 93

Observations from SDO and Hinode provide an unprecedented view of plasma in the solar atmosphere. However the inference of how much material is emitting at each temperature - the Differential Emission Measure DEM - from these data sets is an ill-posed inverse problem. We present a model independent regularization algorithm used in RHESSI X-ray software that makes use of general constraints on the form of the DEM. The regularization produces error and temperature resolution estimates on the calculated DEM, thus giving an objective criteria as to whether the underlying plasma distribution is iso- or multi-thermal. We also investigate how the kernel uncertainties influences the DEM and its accuracy. Our algorithm is computationally fast making it ideal for the challenging amounts of SDO data. We demonstrate this technique applied to synthetic data from a range of DEM models and obtain the regularized DEM from a variety of phenomena observed with SDO and Hinode.

P. Heinzel: Confirmation of prominence oscillations by simultaneous observations from two remote sites
Abstract Author(s): Zapior, M. (1), Kotrc, P. (1), Heinzel, P. (1)
Institution(s): (1) Astronomical Institute, Academy of Sciences
Session: Instabilities, Transients and Eruptions
Poster #: 94

Prominence oscillations are predicted by currently developed MHD models (e.g. Oliver 2009). There are different oscillation modes classified according to the observed amplitudes in the Doppler signal and periods. We concentrated on small-scale oscillations that may be excited by MHD waves in the prominence body. Their observational confirmation is rather difficult due to predicted low amplitudes (1-2 km/s). The signal may be influenced by non-solar factors. A confirmative method for avoiding these problems is an observation of the same prominence by independent remote telescopes. Such observations were made only once by Balthasar et al. (1993) who found 0.5, 12 and 20 minute periods. Here we present the first results of our Czech-Polish observational campaign of prominence oscillations. Two remote telescopes (Ondrejov Observatory and Wroclaw University Observatory), separated by 220 km, observed the same prominence simultaneously with a high temporal resolution. A strong correlation of Doppler signals was revealed and several periods of small scale oscillation were detected. Three periods (22, 28, 45 min) were present in both data sets and therefore considered as real ones. With high spectral resolution we can study the line shape evolution and compare our results with theoretical models (see contribution by Heinzel et al. at this meeting).

J. Lin: Small Scale Structures inside the Reconnecting Current Sheet: Observations and Theories
Abstract Author(s): Lin, J. (1)
Institution(s): (1) Yunnan Astronomical Observatory, Kunming, China
Session: Instabilities, Transients and Eruptions
Poster #: 95

One of the most significant predictions of the catastrophe model of solar eruptions developed by Lin & Forbes (2000) is a long current sheet that forms following the onset of the eruption. Various modes of plasma turbulence as a result of plasma instabilities are invoked inside the current sheet, yielding fast dissipation of the magnetic field, namely magnetic reconnection, through the sheet. Because the timescale of reconnection is long compared to the timescale of the onset stage, dissipation of the sheet is slow, so the current sheet is able to become fairly long. The evolution in the global feature of the current sheet is significant constrained by the local Alfven speed, and the internal properties and features of the sheet, on the other hand, are dependent in an apparent way on the development of the turbulence caused by the instabilities. The tearing mode instability among those that may occur in the sheet is the most important one that accounts for the large thickness and high electric resistivity of the current sheet. In the present work, we show a set of events that were observed to develop long and thick current sheets with several apparent features indicating the progress of the turbulence in the sheet, and the results of numerical experiments of magnetic reconnection occurring in a long current sheet. We noticed that apparent features of the tearing usually appear in the environment of high magnetic Reynolds number, and numerical experiment duplicated the scaling of the current sheet deduced on the basis of the tearing mode.

J. Posson-Brown: Flare detection in Hinode XRT lightcurves
Abstract Author(s): Posson-Brown, J. (1), Kashyap, V. (1), Grigis, P. (1)
Institution(s): (1) Harvard-Smithsonian Center for Astrophysics
Session: Instabilities, Transients and Eruptions
Poster #: 96

One of the greatest challenges in solar coronal physics is to obtain a statistically complete sample of short duration events like coronal bright points. Such samples are necessary to fully characterize the properties of these events and understand the physical basis of such phenomena. Datasets are best acquired automatically, without manual intervention, in order to avoid introducing observer biases. We evaluate several algorithms for detecting flare events in time series data. One algorithm determines where derivatives of the Gaussian-smoothed lightcurves cross certain thresholds. A second algorithm segments the Loess-smoothed lightcurves between consecutive minima, then joins adjacent segments if their extrema are not statistically distinguishable. A third algorithm is a hybrid of the first two. We also investigate the use of a robust Bayesian wavelet-based event detection method. We generate simulated datasets with similar properties to observed Hinode XRT quiet Sun lightcurves and test each algorithm these datasets. The performance of each algorithm on the simulated lightcurves is scored according to the rates of false positive (Type I) and false negative (Type II) errors. We use these results to optimize the parameters values of each algorithm. We compare the performances of the algorithms and evaluate the efficiency with which they are able to detect small events. Such evaluations are relevant to properly interpret the observed steepening of the slope of the solar flare energy distribution at small energies.

S. Pucci: Physical parameters of a blowout jet observed by Hinode XRT and Stereo SECCHI
Abstract Author(s): Pucci, S. (1), Poletto, G. (2), Sterling, A.C. (3), Romoli, M. (4)
Institution(s): (1) Department of Physics and Astronomy, University of Firenze, Firenze, Italy, (2) INAF - Arcetri Astrophysical Observatory, Firenze, Italy, (3) Space Science office, VP 62, Marshall Space Flight Center, Huntsville, AL 35812, USA, (4) Department of Physics and Astronomy, University of Firenze, Firenze, Italy
Session: Instabilities, Transients and Eruptions
Poster #: 97 (Digital Poster Display)

This work presents a multi instrument analysis of the strong X-ray jet which occurred in the north polar coronal hole on 3 nov 2007 at 11:50 UT. The jet has characteristics of a ``blowout jet'' (Moore et al. 2010), and was observed by Hinode XRT over its entire duration (40 minutes) with only the Al-poly filter, used in high cadence (80 images per hour). Stereo EUVI A and B observed the jet at wavelengths 171 Å, 195 Å, 284 Å and 304 Å, with, respectively, cadences of 27, 6, 3 and 6 images per hour. An extension of the jet was also observed with cor1. The EUVI observations allow us to derive the temperature of the jet via the double filter ratios color-color technique (Chae et al.,2002). We are able to calculate temperatures and emission measures in the prejet, the maximum, and the fade-out phases, which are all observed even in the low-cadence 284 filter. These EUVI-derived parameters are then used to calculate a predicted Hinode XRT Al-poly intensity, and we compare that prediction with the observed XRT values. Our results are discussed in terms of the geometrical and physical parameters of the event, with the focus on identifying the characteristics of blow-out jets as observed by the different instruments.

K. Rangaiah: Coronal Rotation from XBPs Observed with Hinode/XRT
Abstract Author(s): Kariyappa, R. (1), DeLuca, E. E. (2)
Institution(s): (1) Indian Institute of Astrophysics, (2) Harvard-Smithsonian Center for Astrophysics
Session: Instabilities, Transients and Eruptions
Poster #: 98

We have selected a large number of XBPs over synoptic soft X-ray full-disk images observed using Al-Mesh with X-Ray Telescope (XRT) onboard the Hinode spacecraft during July-December, 2008. We have analyzed the full-disk images using SSW in IDL. We used the tracer method to identify and trace the passage of XBPs over the solar disc with the help of overlaying grids. We also obtained the position (Latitude and Longitude), size & brightness information for XBPs using tracer method as a function of time and thus calculated sidereal angular rotation rate of corona at different latitudes. We have compared the rotation rate with latitude, size and brightness of XBPs. The important results derived from these analysis are: (i) the rate with which solar corona rotates differentially like the photosphere and chromosphere; (ii) the larger XBPs show a lower sidereal angular rotation rate, the smaller XBPs exhibit higher rotation rate, similar to sunspots; and (iii) it is not clear on brightness of XBPs with coronal rotation rate, needs further investigation.

Y. Su: Structure and Dynamics of Quiescent Prominence Eruptions
Abstract Author(s): Su, Y. (1), Lu, M. (1), van Ballegooijen, A. (1)
Institution(s): (1) Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA
Session: Instabilities, Transients and Eruptions
Poster #: 99 (Digital Poster Display)

We present a survey on the fine structure and dynamics of quiescent prominence eruptions both on the disk and at the limb. We have identified 52 quiescent prominence eruptions by looking at AIA daily movies from April to June in 2011. Among these events, there are 26 symmetric eruptions (coherent loop-like eruptions) and 26 asymmetric eruptions (one footpoint lifts off) as shown by AIA and STEREO/EUVI observations. Vertical threads are identified in 14 out of the 52 events, while horizontal threads are observed in almost all eruptions. We find 17 events with obvious twisting motion, and 10 eruptions seem to untwist from a more complicated structure. For 14 selected limb events, we carry out a detailed study of the eruption dynamics using AIA observations at 304 Angstrom. We find that the initial heights of these erupting prominences are located around 50-110 Mm above the limb. The eruptions start from a speed of less than 5 km/s, then increase to several tens km/s in the AIA field of view. The maximum speed of these events is 50 km/s. The acceleration plots show a positive acceleration in the range of 0 to 20 m/s². No significant difference is identified in the dynamics of the symmetric and asymmetric eruptions.

H. Tian: EUV spectroscopic observations of CME-related kinematics
Abstract Author(s): Tian, H. (1), McIntosh, S. W. (1), Wang, X. (1)
Institution(s): (1) High Altitude Observatory, National Center for Atmospheric Research
Session: Instabilities, Transients and Eruptions
Poster #: 100

CME-related kinematics have rarely been investigated by using EUV spectroscopic observations. We analyzed several data sets obtained by EIS during CMEs and coronal dimmings. CME-related kinematics are clearly revealed in the EIS spectra. Preliminary results are summarized as following: (1) During the eruption phase coronal emission lines often clearly exhibit two components, an almost stationary component accounting for the background emission and a highly blueshifted (~200 km/s) component representing emission from the erupting material. Combining the projected speed of the erupting material derived from imaging observations and the speed of the blueshifted component we can calculate the real speed of the erupting material. (2) A single Gaussian fit of the line profile usually produces large blue shift and greatly enhanced line width, which seems to be the result of the superposition of the two components. (3) The intensity ratio of the blueshifted component and the background component is sometimes larger than 1, and in some cases it decreases with increasing temperature. (3) In one observation we found that the speed of the blueshifted component increases with increasing temperature. (4) Coronal dimming regions are found to be characterized by significant blueshift and enhanced line width by using a single Gaussian fit. While an asymmetry analysis of the line profiles clearly indicates that these are actually caused by the superposition of a strong background component and a relatively weak (~20%) high-speed (~100 km/s) component.

M. Varady: Influence of static and stochastic electric fields on electron beams bombarding the chromosphere
Abstract Author(s): Varady, M. (1,2), Karlicky, M. (2), Moravec, Z. (1)
Institution(s): (1) Purkinje University, Faculty of Science, Usti nad Labem, Czech Republic, (2) Astronomical Institute, Academy of Sciences, Ondrejov, Czech Republic
Session: Instabilities, Transients and Eruptions
Poster #: 101

Using a test-particle approach we study the influence of static andstochastic electric fields on propagation of electron beams along the magnetic fieldlines from the primaryacceleration site in the coronal current sheets downwards to the chromosphere. The results are compared with the most common, classical model of electron beam propagation, scaterring and thermalisation given by Emslie (1978) and theeffects on chromospheric heating and hard X-ray emission are discussed.

M. Varady: RHD Modelling of Solar Flares
Abstract Author(s): Varady, M. (1,2), Kasparova, J. (2), Moravec, Z. (1), Heinzel, P. (2), Karlicky, M. (2)
Institution(s): (1) Purkinje University, Faculty of Science, Usti nad Labem, Czech Republic, (2) Astronomical Institute, Academy of Sciences, Ondrejov, Czech Republic
Session: Instabilities, Transients and Eruptions
Poster #: 102

In the context of interpreting the non-thermal hard X-rayemission and gamma lines emanating from the footpoints of flare loops, mostcontemporary flare models assign a fundamental role during the flare energyrelease, transport and deposition to the high energy non-thermal particlebeams. In our contribution we concentrate on RHD modelling of the spectroscopicproperties of chromospheric flare emission in optical hydrogen linesgenerated due to the bombardment of the chromosphere and photosphere byparticle beams with power-law spectra.

H. Winter: The Neupert Effect as a Function of Pitch Angle Distribution and Energy Budget in Simulated Flares
Abstract Author(s): Winter, H. (1), Reeves, K. (2), Egan, A. (3)
Institution(s): (1) Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA, (2) Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA, (3) Barnard College, NY, NY, USA
Session: Instabilities, Transients and Eruptions
Poster #: 103 (Digital Poster Display)

The Neupert Effect is the well known empirical result that the hard X-ray emission of about half of large, impulsive flares looks like the derivative of the soft X-ray emission. This relationship between the non-thermal, hard X-ray emission and the thermal, soft X-ray emission supports the theory that the majority of the energy liberated by the flare is in the form of non-thermal, high-energy electrons which then heat the thermal plasma and drive chromospheric evaporation. Observational estimates currently put the energy budget of a flare as ~75% in non-thermal processes and ~25% in thermal processes. However, the observational estimates of the thermal and non-thermal energy in flares are currently uncertain to within an order of magnitude. It is also unclear as to why ~24% of large, impulsive flares have their soft X-ray emission peak well before the end of the hard X-ray emission in direct violation of the Neupert Effect. In this work, we address the question of how non-thermal particle properties affect the observed Neupert Effect by simulating a series solar flares using the HyLoop code. HyLoop simulates non-thermal particles interacting a with thermal plasma and the thermal plasma's response to those interactions. A series of flares are simulated with different non-thermal particle parameters, such as pitch-angle distribution and non-thermal fraction of total flare energy. The hard and soft X-rays emissions are synthesized for each simulation. These simulated emissions are then used to determine what impacts the non-thermal particle parameters have on the observed Neupert Effect.

T. Yokoyama: Study of Solar Flare Energetic Electrons by Using Synthesized Emission Based on Fokker-Planck Simulation Results
Abstract Author(s): Yokoyama, T. (1), Kitagawa, H. (1), Minoshima, T. (1), Kawate, T. (1)
Institution(s): (1) U. Tokyo, JAMSTEC, Kyoto U.
Session: Instabilities, Transients and Eruptions
Poster #: 104

Temporal, spatial and spectral variation of emissions from solar flares are studied by solving the electrons transport in a flare loop and their production of photons. The issue of generation mechanisms of high-energy electrons in flares have been known but have not yet understood for more than decades. In observations, for example, the Nobeyama Radioheliograph has made clear descriptions on the gyro-synchrotron emissions from them, such as, relative brighter loop-tops than footpoints, and steeper (softer) spectra toward footpoints. Hinode SOT also observed optical emission from several flares. These observational results should include information on the phase-space-density of injected electrons and could be used as keys to the acceleration mechanisms. It is, however, not straightforward and is a difficult task since such injection information is strongly modulated through the transport and the emission processes. We study this problem by a "forward" approach: First, we solve the electron transport Fokker-Planck equation along a flare loop. The dependence of phase-space density on time, space, electrons pitch-angle, and their energy is derived. The pitch-angle scattering by the Coulomb collisions throughout the loop and the electrons loss at both footpoints are included. Second, the gyro-synchrotron emission (assumed optically-thin) is derived from non-isotropic distribution of emitting electrons. We found that: (1) The loop top is relatively brighter than the footpoints. (2) Both footpoints have steeper (softer) spectrum than the loop top. (3) The emission is harder than what is expected from the isotropic electrons.

K. Kozarev: Solar coronal shocks and particle acceleration as deduced from EUV, radio, and in-situ observations
Abstract Author(s): Kozarev, K. A. (1), Korreck, K. E. (2), Lobzin, V. V. (3), Dayeh, M. A. (4), Schwadron, N. A. (5)
Institution(s): (1) Boston University/Center for Astrophysics, (2) Smithsonian Astrophysical Observatory, (3) The University of Sydney, Sydney, Australia, (4) Soutwest Research Institute, San Antonio, TX, (5) University of New Hampshire, Durham, NH
Session: Instabilities, Transients and Eruptions
Poster #: 105

We use remote ultraviolet and radio observations of the Sun to characterize shocks forming in the low solar corona, and to investigate whether they can accelerate charged particles fast enough for the appropriate timescales of such coronal shocks. We utilize observations from SDO/AIA, and the Learmonth radio observatory. We determine dynamical properties of shock waves, and attempt to estimate relative orientation of the shock fronts to the overlying coronal magnetic fields. In the current theoretical framework of shock acceleration a perpendicular orientation of the shock to magnetic fields is favored for the fast acceleration of charged particles. We use a potential field source surface model of the coronal magnetic fields together with the observations to estimate how efficient coronal shock waves may be in accelerating particles. Finally, we test this approach by analyzing in situ observations during shock wave events.

A. Kobelski: Photometric Uncertainties within XRT
Abstract Author(s): Kobelski, A.R. (1), Saar, S.H. (2), McKenzie, D.E. (1), Weber, M.A. (2), Reeves, K.K. (2), DeLuca E.E. (2)
Institution(s): (1) Montana State University, Bozeman, MT, USA (2) Harvard Smithsonian Center for Astrophysics, Cambridge, MA, USA
Session: Future Needs - Observational, Theoretical and Computational
Poster #: 106 (Digital Poster Display)

We have developed estimates of the systematic photometric uncertainties for the X-Ray Telescope on Hinode. These estimates are included as optional returns from the standard XRT data reduction software, xrt_prep.pro. Included in the software estimates are uncertainties from instrument vignetting, dark current subtraction, split bias leveling, fourier filtering and JPEG compression. Sources of uncertainty that rely heavily on models of plasma radiation or assumptions of elemental abundances, such as photon noise, are not included in the software. We will present the results of this study, and discuss their implementation into the xrt data analysis pipeline.

N. Uribe-Patarroyo: The emergent technology of space-qualified liquid-crystal variable retarders for solar remote sensing
Abstract Author(s): Uribe-Patarroyo, N. (1)
Institution(s): n/a
Session: Future Needs - Observational, Theoretical and Computational
Poster #: 107

New instruments for the study of solar magnetic fields that make use of liquid-crystal modulators have appeared and are being designed recently. Among them, the successful Imaging Magnetrograph eXperiment (ImaX) onboard the SUNRISE mission used two liquid-crystal variable retarders (LCVRs) as polarization modulators, which performed exceptionally well in this ballon-borne mission, with near-space environmental requirements. IMaX served as the seed for the Solar Orbiter Helioseismic Polarimetric Imager (SO/PHI), which is approaching its preliminary design phase, in which LCVRs form the basis of the polarization modulation package.Motivated by the requirements of SO/PHI and Solar Orbiter's coronagraph METIS/COR, our group performed the project "Validation of LCVRs for the Solar Orbiter Polarization Modulation Package", as required by the European Space Agency to increase the LCVR technology readiness level to TRL5 "Component Validation in Relevant Environment".We present the main results of this project: the environmental testing of LCVRs under space conditions, including a campaign to test the effects of gamma and proton radiation, outgassing, vibration and shock, thermo-vacuum and ultraviolet radiation. It can be concluded that LCVRs are insensitive to high-energy radiation, vibration and shock and thermo-vacuum. The degradation induced by ultraviolet radiation is known, and our study established precise effects for different liquid crystals, which consisted in a progressive change in the performance, but not in destruction of the samples up to the tested levels.The results of this validation can be extrapolated into other uses of liquid-crystal variable retarders, such as in tunable Lyot filters, application which is being considered for Solar-C, and provide a significant step towards full space qualification of high-performance LCVRs for space applications.(*) currently at Iberoptics Sistemas pticos, C/ Gamonal 16, Of. 4-1, E-28031 Madrid, Spain; and Department of Electrical & Computer Engineering, Boston University, Boston, Massachusetts 02215, USA

E. DeLuca: The X-ray Telescope & Spectrograph - Coronal Instrumentation for the Solar-C Mission
Abstract Author(s): DeLuca, E. E. (1), Golub, L. (1), Kobayashi, K. (2), Bookbinder, J. (1), Cheimets, P. (1), Lemen, J.(3), Loncope, D. (4), McKenzie, D. (4), Korreck, K. (1), Reeves, K. (1), Weber, M. (1), Winbarger, A. (5)
Institution(s): (1) CfA, (2) UAH, (3) LMSAL, (4) MSU, (5) MSFC
Session: Future Needs - Observational, Theoretical and Computational
Poster #: 108

The Solar-C Plan-B mission described in the Interim Report emphasizes the importance of coronal imaging and spectroscopy for the success of the mission. We describe an instrument suite that combines high resolution imaging (0.5"/pixel) and high resolution spectroscopy (1"/pixel, 5mA/pixel, 70km/s). The X-ray Telescope & Spectrograph (XTS) fits in the baseline volume and mass described in the Interim Report. It consists of a GI imager channel (XTS-I) feeding a low noise rapid read (~700fps) CMOS detector and an X-ray slit spectrograph channel (XTS-S) based on the MaGIXS rocket design.

R. Kano: Instrument for the Chromospheric Lyman-Alpha SpectroPolarimeter (CLASP) program
Abstract Author(s): Kano, R. (1), Narukage, N. (2), Ishikawa, R. (1), Kubo, M. (1), Katsukawa, Y. (1), Suematsu, Y. (1), Hara, H. (1), Bando, T. (1), Tsuneta, S. (1), Watanabe, H. (3), Ichimoto, K. (3), Kubo, M. (4), Song, D. (5), Kobayashi, K. (6), Trujillo Bueno, J. (7)
Institution(s): (1) National Astronomical Observatory of Japan, Tokyo, Japan, (2) Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Kanagawa, Japan, (3) Kyoto University, Kyoto, Japan, (4) Meisei University, Tokyo, Japan, (5) Soul National University, Soul, Korea, (6) University of Alabama in Huntsville, Huntsville, AL, USA, (7) Instituto de Astrofisica de Canarias, Tenerife, Spain
Session: Future Needs - Observational, Theoretical and Computational
Poster #: 109

The "Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP)" is a sounding rocket experiment to explore magnetic fields in the upper chromosphere and transition region by measuring the linear polarization in the Lyman-alpha line (121.567nm). The Lyman-alpha line from on-disk targets must be linearly polarized by scattering processes, and the linear polarization at the line center is expected to vary between 0.1~1% by the Hanle effect depending on the strength and orientation of magnetic fields. Therefore, the CLASP instrument is designed to measure the linear polarization with a polarimetric sensitivity of 0.1% and a spectral resolution of 0.01nm. The instrument consists of a large aperture (287 mm) Cassegrain telescope, a grating spectrograph, and a polarimeter. Reflective optical elements are essentially used there, because optical materials, with a few exceptions (e.g. Magnesium Fluoride, MgF2), easily absorb the Lyman-alpha light. The primary mirror of the telescope uses a narrowband multilayer coating that reflects the Lyman-alpha but transmits the visible light onto an absorber behind the primary mirror. This minimizes both the heat load and off-band contamination in the spectrograph. A constant-line-spacing spherical grating mounted in an inverse Wadsworth geometry disperses the light from the 1.6"-slit on the Cassegrain focus into two channels: plus and minus 1st-order beams. They are a matched pair of imaging systems consisting of an offset parabolic mirror, a reflective polarization analyzer placed at the Brewster's angle, and a CCD camera for each, and simultaneously measure the orthogonal linear polarizations. A rotating half waveplate made of MgF2 is behind the slit, and allows measurement of both Stokes Q and U with the fixed polarization analyzers.

H. Lin: Observing the Dynamic Sun with SPIES
Abstract Author(s): Lin, H. (1)
Institution(s): (1) Institute for Astronomy - University of Hawaii
Session: Future Needs - Observational, Theoretical and Computational
Poster #: 110 (Digital Poster Display)

The SpectroPolarimetric Imager for the Energetic Sun (SPIES) is a newinstrument optimized for the study of the small scale and highly dynamicsolar phenomena such as the ubiquitous penumbral micro jets or surfacedynamo associated with the solar convective motion. Understanding thephysics of these dynamic phenomena requires detailed information of themagnetic, thermal, and dynamic properties of the solar atomsphere atevery stage of their evolutionary history. Although these properties canbe obtained with existing high performance spectropolarimeters such as theSpectroPolarimeter on board the Hindoe space solar observatory, or theFacility IR Spectropolarimeter off the Dunn Solar Telescope, theseinstruments cannot yet observe with time resolution comparable to thedynamic time scale of these dynamic events over the required field ofview. SPIES is a true-imaging spectropolarimeter specifically constructedto address this deficiency in our observing capability. It is based ona fiber optic array integral field unit, and is capable of observing a64 x 32 pixels field simultaneoulsy with high spatial and spectralresolution. It can obtain the full Stokes spectra of the field with atemporal resolution of a few seconds. This paper presents the design andcharacteristics of the instrument, as well as preliminary results froma sunspot magnetic field observation using the FeI 1565 nm line pair.

J. Martinez-Sykora: Realistic simulations of the impact of partial ionization on the chromosphere
Abstract Author(s): Martinez-Sykora, J. (1)
Institution(s): (1) Lockheed Martin Solar & Astrophysics Lab, Palo Alto, CA, USA, (2) Instute of theoretical Astrophysic, University of Oslo, Norway
Session: Future Needs - Observational, Theoretical and Computational
Poster #: 111

We investigate the importance and xonsequences of introducing neutral particles into the MHD equations in 3D advanced radiativeMHD simulations obtained from the Bifrost code. We use a model that spans the upper layer of the convection zone to the low corona. The chromosphere and transition region is partially ionized and the interaction between ionized particles and neutral particles has important consequences on the thermodynamics of these layers.We implemented the effects of the partial ionization using the generalized Ohm's law, i.e., we consider the effects of the Hall and ambipolar diffusion in the induction equation. The different approximations going from 3 particles to the generalized Ohm's law has been tested in 2.5D simulations and we note that the assumptions behind the generalized Ohm's law are not alway satisfied in the upper-chromosphere and in the transition region.

T. Ayres: Warm Coronal Rain on Young Solar Analog, EK Draconis?
Abstract Author(s): Ayres, T. (1), France, K. (1)
Institution(s): (1) University of Colorado
Session: Solar-Stellar Connections
Poster #: 112

We have obtained a moderate resolution (R~ 18,000), 129-143 nm spectrum of 50 Myr old solar analog EK Draconis, using the super-sensitive Cosmic Origins Spectrograph on Hubble Space Telescope. The brief twenty-minute "SNAPshot" observation, remarkably, captured two distinct flares-like enhancements in the Si IV 140 nm doublet (T~ 60,000 K); unusually broad profiles of Si IV and the C II 133 nm chromospheric multiplet (T~ 30,000 K); and very prominent Fe XXI 135 nm coronal forbidden line emission (T~ 10 MK). The bright Si IV features are significantly redshifted compared to the milder, although still redshifted, equivalent components of Alpha Centauri A, a close twin of the Sun. The broad, shifted, flaring hot-line profiles of EK Dra reveal not only that the subcoronal plasma of the young sun is highly dynamic, but also that the Si IV-bearing gas must be continually accreting onto the lower atmosphere, perhaps the stellar equivalent of warm "coronal rain." Furthermore, the erratically variable Si IV emission is not matched in the neighboring temperature regimes, traced by chromospheric C II and coronal Fe XXI; so the Si IV outbursts do not correspond to the normal flare process, which impulsively heats coherently through the atmosphere. Instead, the Si IV events more likely represent episodes of catastrophic cooling: cloud-bursts associated with the coronal rain, if you will.

S. Saar: Calibrating the Solar-Stellar Coronal Connection: Using Hinode XRT to Measure Stellar Coronae
Abstract Author(s): Saar, S. H. (1), Testa, P. (1)
Institution(s): (1) Smithsonian Astrophysical Observatory
Session: Solar-Stellar Connections
Poster #: 113

Despite decades of X-ray observations of both solar and stellarcoronae with various instruments, the precise position of solarX-ray emission levels in a broader astrophysical context issurprisingly uncertain. This is largely due to cross-calibrationproblems and the difficulty in observing the same targets with bothsolar and stellar instruments. Here we report on a new attempt atdirect cross-calibration between solar and stellar missions:observations by Hinode XRT of a young, X-ray active F star HD199143. This star has been previously studied by ROSAT and Chandra,and is eclipsed by the Sun every January. We observed the star inthe Al-poly filter for a total of ~12 hours on ingress andegress. After careful data processing, we searched for a smallexcess along the star's apparent path. We discuss the tentativelysuccessful results in the context of the most up-to-date calibrationsof Hinode, Chandra and ROSAT count rates for this star, as well asfurther observational and analysis plans.

S. Saar: Mass and Energy Loss Due to CMEs Throughout the Sun's History
Abstract Author(s): Saar, S. H. (1), Korreck, K. (1), Aarnio, A. (2)
Institution(s): (1) Smithsonian Astrophysical Observatory, (2) University of Michigan
Session: Solar-Stellar Connections
Poster #: 114

We combine solar CME statistics, the fraction of flares by energy with associated CMEs, and stellar flare statistics by energy to make estimates of the mass and kinetic energy loss due to CMEs in stars as a function of their mean X-ray luminosity. We then use X-ray - rotation and rotation - age relationships to convert these into estimates of the CME-related mass and energy losses as afunction of age. We find that in younger stars, CME-related mass loss can be a significant fraction of the total. In support ofthis, our estimates match observed mass loss rates in two active stars. We estimate the time history of solar mass loss due to CMEs.

D. Graham: DEM analysis at impulsive phase footpoints
Abstract Author(s): Graham, D. R. (1), Fletcher, L. (1), Hannah. I. G. (1), Kontar, E. P. (1)
Institution(s): (1) School of Physics and Astronomy, University of Glasgow, UK, G12 8QQ
Session: Instabilities, Transients and Eruptions
Poster #: 115

The chromospheric footpoints of a solar flare in the impulsive phase have been observed to be locations of high electron density and temperature. The depth in the atmosphere where this emission originates, and how it is formed are still relatively unanswered questions. The differential emission measure (DEM) is a useful tool to study the temperature structure of a plasma, showing the amount of emitting plasma as a function of temperature. We have used the regularised inversion method by I. G. Hannah and E. P. Kontar to calculate the DEM at the footpoints of a solar flare. Spectral data from SDO/EVE and Hinode/EIS provide EUV emission lines in a wide range of temperatures. The combination of high cadence and wavelength coverage from EVE, and high spatial/spectral resolution from EIS are ideal for this task and will hopefully shed light on the character of flare footpoint plasma.