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C. Z. Cheng, G. S. Choe (Princeton Plasma Physics Laboratory)
Based on resistive magnetohydrodynamic simulations, a solar flare model is presented, which can explain development of different phases and homologous recurrence of solar flares. When a magnetic arcade is sheared, a current sheet is formed and magnetic reconnection can take place to form a magnetic island. In the underlying arcade, a continuing increase of magnetic shear can trigger a new reconnection process and create another island. The newborn island rapidly rises and merges with the pre-existing island to form one integrated island. Before merging with the upper island, the newborn island exhibits two different phases of rising motion: a slower first phase and a faster second phase. The first phase, in which reconnection of line-tied fields in the underlying arcade progresses rather slowly, may be related with the preflare phase. In the second phase, the island coalescence creates an elongated current sheet below the rising island and enhances the reconnection of line-tied arcade fields. This phase can be interpreted as the impulsive phase or a flash phase of flares. After merging of the islands, magnetic reconnection of the arcade field gradually fades out over a few hours. This rather long period can be considered as the main phase of flares. The sequence of all these processes is repeated with some time interval while magnetic shear is being replenished. We propose that a series of these flaring processes constitutes a set of homologous flares.
The author(s) of this abstract have provided an email address for comments about the abstract: fcheng@pppl.gov
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Bulletin of the American Astronomical Society, 34
© 2002. The American Astronomical Soceity.