EVIDENCE FOR MAGNETIC RECONNECTION IN LARGE-SCALE MAGNETIC-STRUCTURES IN SOLAR-FLARES

Modelling the observed vertical magnetic field of an active region (NOAA 2372) for two consecutive days, April 7 and 8, 1980, by the potential field of an ensemble of magnetic dipoles, we derived the location of the separatrices, surfaces that separate cells of different field line connectivities, and of the separator which is the intersection of the separatrices. The overall temporal evolution of the magnetic fields and the location of the off-band Halpha kernels of flares, that occurred before the obtention of the magnetograms, support the hypothesis that the flares were due to magnetic reconnection taking place in the main separator of the active region. The triggering of reconnection in a second separator appearing on April 8 by reconnection in the main separator is strongly suggested by the observed magnetic connectivities and the kernels locations. The location of the emerging currents on the separatrices support the idea that flares are feeded by the release of magnetic free energy.