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Title: Three-dimensional magnetic restructuring in two homologous solar flares in the seismically active NOAA AR 11283

We carry out a comprehensive investigation comparing the three-dimensional magnetic field restructuring, flare energy release, and the helioseismic response of two homologous flares, the 2011 September 6 X2.1 (FL1) and September 7 X1.8 (FL2) flares in NOAA AR 11283. In our analysis, (1) a twisted flux rope (FR) collapses onto the surface at a speed of 1.5 km s{sup –1} after a partial eruption in FL1. The FR then gradually grows to reach a higher altitude and collapses again at 3 km s{sup –1} after a fuller eruption in FL2. Also, FL2 shows a larger decrease of the flux-weighted centroid separation of opposite magnetic polarities and a greater change of the horizontal field on the surface. These imply a more violent coronal implosion with corresponding more intense surface signatures in FL2. (2) The FR is inclined northward and together with the ambient fields, it undergoes a southward turning after both events. This agrees with the asymmetric decay of the penumbra observed in the peripheral regions. (3) The amounts of free magnetic energy and nonthermal electron energy released during FL1 are comparable to those of FL2 within the uncertainties of the measurements. (4) No sunquake was detected in FL1; in contrast,more » FL2 produced two seismic emission sources S1 and S2 both lying in the penumbral regions. Interestingly, S1 and S2 are connected by magnetic loops, and the stronger source S2 has a weaker vertical magnetic field. We discuss these results in relation to the implosion process in the low corona and the sunquake generation.« less
Authors:
; ; ;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6]
  1. Space Weather Research Laboratory, New Jersey Institute of Technology, University Heights, Newark, NJ 07102-1982 (United States)
  2. Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig Weg 3, D-37077 Göttingen (Germany)
  3. Center for Space Plasma and Aeronomic Research, The University of Alabama in Huntsville, Huntsville, AL 35805-1911 (United States)
  4. Code 671, NASA Goddard Space Flight Center, Greenbelt, MD 20771-2400 (United States)
  5. IGAM-Kanzelhöle Observatory, Institute of Physics, University of Graz, Universitätsplatz 5, A-8010 Graz (Austria)
  6. Centre from Stellar and Planetary Astrophysics, School of Mathematical Sciences, Monash University, Melbourne, Victoria 3800 (Australia)
Publication Date:
OSTI Identifier:
22369998
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 795; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASYMMETRY; DECAY; ELECTRONS; EMISSION; ERUPTION; GAMMA RADIATION; IMPLOSIONS; MAGNETIC FIELDS; SOLAR FLARES; SUN; SURFACES; THREE-DIMENSIONAL CALCULATIONS; VELOCITY; X RADIATION