Triennial Earth-Sun Summit (TESS) Indianapolis, IN – 27- 30 April, 2015 Meeting Abstracts 100 – Plenary Talk: Toward a Better Understanding of the Solar Atmosphere: Combining Observations and Numerical Modeling, Bart De Pontieu (Lockheed- Martin) 100.01 – Toward a Better Understanding of the Solar Atmosphere: Combining Observations and Numerical Modeling The study of the Sun, our nearest star, is making rapid progress, through a combination of a host of new space-based and ground-based observatories coming online and major advances in numerical simulations that incorporate increasingly complex physical mechanisms. I will provide an overview of some recent exciting discoveries that highlight the synergy between numerical modeling and observations with the Interface Region Imaging Spectrograph (IRIS), Solar Dynamics Observatory (SDO) and Hinode spacecraft. Some of the topics I will discuss include: 1. recent advances in understanding the dominant heating mechanism(s) of the solar atmosphere focusing on dissipation of Alfven waves, as well as the presence of non-thermal particles in small heating events resulting from magnetic reconnection; 2. heating and reconnection in the partially ionized chromosphere; 3. the origin of the slow solar wind; 4. the global nature and long-distance connections governing the instability of the solar atmosphere and driving eruptions such as coronal mass ejections. Author(s): Bart De Pontieu1 Institution(s): 1. Lockheed Martin Solar & Astrophysics Laboratory 101 – Plenary Talk: The Magnetosphere as a Component of the Interconnected Sun-Geospace System, Janet Kozyra (University of Michigan) 101.01 – The Magnetosphere as a Component of the Interconnected Sun-Geospace System This presentation focuses on the magnetosphere as an essential component of a vast interlocking system that spans from the Sun to the upper atmosphere and beyond. The magnetosphere is itself a system, as are the other components. Each part of the magnetosphere feels the influence of the whole Sun-Geospace system and, in turn, the magnetosphere, as a component, feeds back to influence parts of the larger system. Solar disruptions that ultimately reach Earth are modified by propagation through the heliosphere sometimes changing from harmless disturbances into triggers for major space storms by the time they impact and disrupt the magnetosphere. The magnetosphere is so intimately connected to the ionosphere - upper atmosphere that they operate as one in response to changing solar conditions. Some recent results from remote sensing and multi-satellite observations as well as global models will be presented that give insights into the magnetosphere and its linkages during extreme events. These events are broadly defined to include super-storms, intense auroral activity, large radiation belt disturbances, unusual features appearing during moderate activity, and/or conditions in the solar wind, that are far from the typical range. A challenge arises because much of the system behavior is contained in the coupling and not in the individual processes. In addition, extreme features can develop as a result of the chance overlap in space and/or time of usually isolated processes. To answer these challenges, the whole-system investigation of extreme events has emerged as an important research area in a variety of scientific disciplines. The whole-system approach makes it possible to start with an extreme feature in the magnetosphere and then track back through the Sun-Geospace system to identify the environmental conditions and interacting physical processes that produced it. New information about the magnetosphere and its linkages will be presented that resulted from a whole system investigation of the unusual 21 January 2005 magnetic storm. In addition, new discipline-focused questions will be described that arose about contributing processes because of this different perspective. Author(s): Janet Kozyra1 Institution(s): 1. University of Michigan 102 – Magnetic Reconnection Posters 102.01 – Magnetic Reconnection Onset and Energy Release at Current Sheets Reconnection and energy release at current sheets are important at the Sun (coronal heating, coronal mass ejections, flares, and jets) and at the Earth (magnetopause flux transfer events and magnetotail substorms) and other magnetized planets, and occur also at the interface between the Heliosphere and the interstellar medium, the heliopause. The consequences range from relatively quiescent heating of the ambient plasma to highly explosive releases of energy and accelerated particles. We use the Adaptively Refined Magnetohydrodynamics Solver (ARMS) model to investigate the self-consistent formation and reconnection of current sheets in an initially potential 2D magnetic field containing a magnetic null point. Unequal stresses applied to the four quadrants bounded by the X-line separatrix distort the potential null into a double-Y-type current sheet. We find that this distortion eventually leads to onset of fast magnetic reconnection across the sheet, with copious production, merging, and ejection of magnetic islands due to plasmoid instability. In the absence of a mechanism for ideal instability or loss of equilibrium of the global structure, however, this reconnection leads to minimal energy release. Essentially, the current sheet oscillates about its force-free equilibrium configuration. When the structure is susceptible to a large-scale rearrangement of the magnetic field, on the other hand, the energy release becomes explosive. We identify the conditions required for reconnection to transform rapidly a large fraction of the magnetic free energy into kinetic and other forms of plasma energy, and to restructure the current sheet and its surrounding magnetic field dramatically. We discuss the implications of our results for understanding heliophysical activity, particularly eruptions, flares, and jets in the corona. Our research was supported by NASA’s Heliophysics Supporting Research and Living With a Star Targeted Research and Technology programs. Author(s): C R DeVore1, Spiro K Antiochos1 Institution(s): 1. NASA GSFC 102.02 – The plasmoid instability during magnetic reconnection in partially ionized chromospheric plasmas Magnetic reconnection is a ubiquitous process in the partially ionized solar chromosphere. Recent 2D simulations have shown that the plasmoid instability onsets during partially ionized reconnection [1-3]. We use the plasma-neutral module of the HiFi framework to simulate the nonlinear evolution of the plasmoid instability during symmetric and asymmetric reconnection. These simulations model the plasma and neutrals as separate fluids and include ionization, recombination, the Hall effect, charge exchange, thermal conduction, and optically thin radiative cooling. As in previous simulations [1,2], an enhancement of plasma density in the current sheet and plasmoids leads to recombination being an important loss term in the plasma continuity equation. The Hall term leads to the development of significant out-of-plane magnetic fields in the current sheet region, but we do not observe shortening of the current sheet or acceleration of the reconnection rate as a result. Secondary merging of magnetic islands is modified by inflow asymmetry and often results in an enhancement of the core field in the resulting islands. [1] Leake et al. 2012, ApJ, 760, 109 [2] Leake et al. 2013, PhPl, 20, 062102 [3] Ni et al. 2015, ApJ, 799, 79 Author(s): Nicholas A Murphy2, Vyacheslav S Lukin1 Institution(s): 1. National Science Foundation, 2. Smithsonian Astrophysical Observatory 102.03 – Dynamical signatures of magnetic neutral lines in the geomagnetic tail We consider dynamical signatures of charge particle motion that discriminate between a current sheet magnetic field reversal, characteristic of quiet times in the magnetosphere, and a magnetic neutral line field, which would be produced by magentic reconnection during active times. We concentrate on potential signatures that follow from the fundamental dynamics of ions or electrons. Previous work has shown such signatures to be both observable and robust. Dynamics in both the current sheet and neutral line fields exhibits chaotic scattering over a wide range of parameter values. In this work we consider the problem of discrimination between these two magnetic structures using the properties of this scattering. In particular we investigate the differences in resonance behavior as the particle energy is varied, as well as the possibility that fractal exit region structuring could discriminate the two fields. Application to the magnetotail will be presented. Author(s): Richard F Martin1, Daniel L Holland1 Institution(s): 1. Illinois State University 103 – Solar Interior Posters 103.01 – Pixel Dynamics Analysis of Photospheric Spectral Data Recent advances in solar observations have led to higher-resolution surface (photosphere) images that reveal bipolar magnetic features operating near the resolution limit during emerging flux events. Further improvements in resolution are expected to reveal even smaller dynamic features. Such photospheric features provide observable indications of what is happening before, during, and after flux emergence, eruptions in the corona, and other phenomena. Visible changes in photospheric active regions also play a major role in predicting eruptions that are responsible for geomagnetic plasma disturbances. A new method has been developed to extract physical information from photospheric data (e.g., SOLIS Stokes