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Title: THE MAGNETIC SYSTEMS TRIGGERING THE M6.6 CLASS SOLAR FLARE IN NOAA ACTIVE REGION 11158

We report a detailed event analysis of the M6.6 class flare in the active region (AR) NOAA 11158 on 2011 February 13. AR 11158, which consisted of two major emerging bipoles, showed prominent activity including one X- and several M-class flares. In order to investigate the magnetic structures related to the M6.6 event, particularly the formation process of a flare-triggering magnetic region, we analyzed multiple spacecraft observations and numerical results of a flare simulation. We observed that, in the center of this quadrupolar AR, a highly sheared polarity inversion line (PIL) was formed through proper motions of the major magnetic elements, which built a sheared coronal arcade lying over the PIL. The observations lend support to the interpretation that the target flare was triggered by a localized magnetic region that had an intrusive structure, namely, a positive polarity penetrating into a negative counterpart. The geometrical relationship between the sheared coronal arcade and the triggering region is consistent with the theoretical flare model based on the previous numerical study. We found that the formation of the trigger region was due to the continuous accumulation of small-scale magnetic patches. A few hours before the flare occurred, the series of emerged/advected patches reconnectedmore » with a pre-existing field. Finally, the abrupt flare eruption of the M6.6 event started around 17:30 UT. Our analysis suggests that in the process of triggering flare activity, all magnetic systems on multiple scales are included, not only the entire AR evolution but also the fine magnetic elements.« less
Authors:
;  [1] ; ; ;  [2] ;  [3]
  1. Department of Earth and Planetary Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)
  2. Solar-Terrestrial Environment Laboratory, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601 (Japan)
  3. School of Space Research, Kyung Hee University, Yongin, Gyeonggi-do 446-701 (Korea, Republic of)
Publication Date:
OSTI Identifier:
22130981
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 773; 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; COMPUTERIZED SIMULATION; ERUPTION; MAGNETISM; NUMERICAL ANALYSIS; PROPER MOTION; SHEAR; SOLAR FLARES