QUANTIFICATION OF THERMAL RESPONSE DRIVEN BY ELECTRON ACCELERATION IN SOLAR FLARES

OBJECTIVES. THIS PROPOSAL SEEKS SUPPORT FOR FOCUSED DATA ANALYSIS TO QUANTIFY THE RELATIONSHIPS BETWEEN THE NONTHERMAL COMPONENT OF FLARE-ACCELERATED ELECTRONS AND THE THERMAL RESPONSE DRIVEN BY THEM IN COLD SOLAR FLARES A SUBSET OF EARLY IMPULSIVE FLARES WITH A RELATIVELY MODEST THERMAL RESPONSE. THE GOAL OF THIS RESEARCH IS TO OBTAIN NEW KNOWLEDGE ABOUT THE PHYSICAL ENVIRONMENT OF SUCH COLD SOLAR FLARES INCLUDING THE 3D DISTRIBUTION OF THE MAGNETIC FIELD THERMAL PLASMA AND ACCELERATED ELECTRONS. A SPECIFIC GOAL OF THE PROJECT IS TO OBTAIN QUANTITATIVE INFORMATION ABOUT THE FLARING VOLUME AND HOW THE PARAMETERS OF THE SOLAR FLARE SUCH AS FAST-ELECTRON AND THERMAL-PLASMA DISTRIBUTIONS ARE COUPLED AND EVOLVE IN TIME WITHIN THE VOLUME. SIGNIFICANCE. THIS PROPOSAL ADDRESSES A FUNDAMENTAL HIGH PRIORITY PROBLEM IN SOLAR PHYSICS: HOW EXACTLY THE COUPLED MAGNETIC THERMAL AND NONTHERMAL ENERGIES IN THE IMPULSIVE PHASE OF SOLAR FLARES EVOLVE AND TRANSFORM FROM ONE TO ANOTHER. THIS RESEARCH IS TIMELY: FROM YEARS OF JOINT RHESSI AND SDO OBSERVATIONS WE HAVE IDENTIFIED A LIST OF COLD FLARES WITH DATASETS PERFECTLY SUITED TO QUANTITATIVELY ADDRESS THE PROPOSAL OBJECTIVES WHILE THE KEY TECHNIQUES FOR THE DATA ANALYSIS HAVE ALREADY BEEN DEVELOPED. RELEVANCE. OUR MULTI-WAVELENGTH DATA ANALYSIS PROGRAM AS PROPOSED HERE IS EXPLICITLY AND HIGHLY RELEVANT TO THE FIRST GOAL OF THE HELIOPHYSICS DECADAL SURVEY DETERMINE THE ORIGINS OF THE SUN S ACTIVITY AND PREDICT THE VARIATIONS IN THE SPACE ENVIRONMENT AND TO THE FOURTH DECADAL SURVEY GOAL DISCOVER AND CHARACTERIZE FUNDAMENTAL PROCESSES THAT OCCUR BOTH WITHIN THE HELIOSPHERE AND THROUGHOUT THE UNIVERSE. THIS PROGRAM IS DIRECTLY RELEVANT TO THE RHESSI PRIMARY SCIENCE OBJECTIVES: IMPULSIVE ENERGY RELEASE PARTICLE ACCELERATION AND PARTICLE AND ENERGY TRANSPORT AS WELL AS PRIORITIZED SCIENCE GOALS: EVOLUTION OF SOLAR ERUPTIVE EVENTS FLARE-ACCELERATED ELECTRONS AND FLARE-HEATED PLASMA. METHODOLOGY. THE PRIMARY ANALYSIS OF NASA SPACECRAFT DATA PRIMARILY FROM RHESSI AND SDO WILL BE PERFORMED USING STANDARD PUBLICLY AVAILABLE IMAGING AND SPECTRAL FITTING SOFTWARE: INFORMATION ON THE NONTHERMAL ELECTRON POPULATION IS OBTAINED FROM THE RHESSI DATA WHILE INFORMATION ON THE THERMAL PLASMA WILL COME FROM SDO/AIA IN COMBINATION WITH RHESSI DATA. THESE DATA WILL THEN BE CROSS-CORRELATED TO STUDY NONTHERMAL-TO-THERMAL ENERGY PARTITION AS WELL AS SPATIAL DISTRIBUTION AND EVOLUTION OF THE THERMAL AND NONTHERMAL COMPONENTS. TO PUT THESE DATA IN THE 3D CONTEXT WE WILL APPLY EXISTING METHODS OF NONLINEAR FORCE-FREE FIELD EXTRAPOLATIONS BASED ON THE VECTOR PHOTOSPHERIC BOUNDARY CONDITION AVAILABLE FROM SDO/HMI. THE CORRESPONDING MAGNETIC DATA CUBES WILL BE IMPORTED INTO THE GX SIMULATOR PACKAGE AVAILABLE FROM SSW WHICH WE HAVE DEVELOPED PRECISELY FOR THE PURPOSE OF SYNTHESIZING MULTIWAVELENGTH IMAGES INCLUDING X-RAYS AND EUV WITH A 3D MODEL OF THE FLARING VOLUME TO BE DEVELOPED AND VALIDATED VIA COMPARISON OF THE SYNTHETIC EMISSION WITH OBSERVATIONAL CONSTRAINTS. ACHIEVING THE PROJECT OBJECTIVES WILL BE DONE VIA QUANTITATIVE ANALYSIS OF THE DATA DATA PRODUCTS AND RECONSTRUCTION OF 3D MODELS OF THE STUDIED FLARES. ALL REQUIRED MODELING TOOLS ARE ALREADY AVAILABLE. PROPOSED WORK. FOR EACH FLARE FROM OUR FLARE LIST WHICH CURRENTLY CONTAINS MORE THAN TEN FLARES JOINTLY OBSERVED BY RHESSI AND SDO AND ONE OF THEM ALSO IRIS DATA WE WILL OBTAIN SPATIAL AND SPECTRAL DATA ON THE NONTHERMAL ELECTRONS FROM THE X-RAY DATA AND ON THE THERMAL PLASMA IN THE FORM OF A DEM DERIVED FROM THE EUV DATA WITH THE HIGHEST POSSIBLE CADENCE. SDO/AIA DATA WILL ALSO BE USED TO CONSTRAIN THE FLARE LOOP MORPHOLOGY. THE WORKFLOW WILL INCLUDE PERFORMING NONLINEAR FORCE-FREE EXTRAPOLATIONS DEFINING CORONAL THERMAL AND NONTHERMAL STRUCTURE SIMULATING THE OBSERVED EMISSIONS AND COMPARING WITH OBSERVATIONS THUS VALIDATING THE SPECIFIC 3D FLARE MODEL.