Spatial Relationship between Twist in Active Region Magnetic Fields and Solar Flares

Twisted magnetic field lines in solar active regions constitute stressed flux systems, the reconnection of which can release the stored (excess) magnetic energy in the form of solar flares. Using co-registered photospheric vector magnetograms and chromospheric Ha images for 29 flares, we explore the...

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Bibliographic Details
Published in:The Astrophysical journal 2005-08, Vol.629 (2), p.1135-1140
Main Authors: Hahn, Michael, Gaard, Stacy, Jibben, Patricia, Canfield, Richard C, Nandy, Dibyendu
Format: Article
Language:English
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Summary:Twisted magnetic field lines in solar active regions constitute stressed flux systems, the reconnection of which can release the stored (excess) magnetic energy in the form of solar flares. Using co-registered photospheric vector magnetograms and chromospheric Ha images for 29 flares, we explore the spatial relationship between these flares and the magnetic topology of the active regions in which they occur. We find two dominant trends. First, flares are preferentially initiated in subregions that have a high gradient in twist. Second, flare initiation occurs close to chirality inversion lines (which separate regions with twist of opposite handedness). Our results demonstrate that magnetic helicity, as manifested in the twist parameter, plays an important role in magnetic reconnection and solar flaring activity.
ISSN:0004-637X
1538-4357
DOI:10.1086/431893