We studied magnetic fields in a 1F/2.4C solar flare using the BBSO and SOHO/MDI observations of an active region NOAA 8375. The active region produced a multitude of subflares, many of them were clustered along the moat boundary in the area with mixed polarity magnetic fields. The study showed that the flaring magnetic configuration consisted of two magnetic loops, which approached each other and reconnected. The flare followed by the photospheric cancelation of magnetic flux of 3 x 1019 Mx h-1. We observed strong upward directed plasma flows at the cancelation site. We find that the reconnection rate of 0.5 km s-1 is a significant fraction of Alfven speed, which is a strong evidence for fast photospheric reconnection happening in the flare. Application of the Sweet-Parker model to the observed flare showed that the model provides adequate description of photospheric reconnection.
©BBSO/NJIT Seminar on OCT 99, 2000