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M. Kundu, V.I. Garaimov (Dept. of Astronomy, U. Maryland)
We discuss a particular spatial configuration of a special class of microwave flaring regions (first identified by Hanaoka) in which the primary energy release results from the interaction between emerging magnetic flux and an existing overlying region. Such events typically exhibit radio and X-ray emission at the main flare site (the site of interaction) and in addition radio emission at a remote site up to 2 x 105 km away in another active region. We have identified and studied more than a dozen microwave flares in this class, in order to arrive at some general conclusions on reconnection and energy release in such solar flares. Typically, these flares show a gradual rise showing many subsidiary peaks in both radio and hard X-ray light curves with a quasi-oscillatory nature with periods of 5-6 seconds, the presence of a bright compact X-ray-emitting loop in the main flare source, a delay of the radio emission from the remote source relative to the main X-ray-emitting source, higher circular polarization in the radio emission of the remote source than in the main source, and stronger photospheric magnetic field in the remote source. We show that the magnetic field in the main flare site changes sharply at the time of the flare, and that the remote site is magnetically connected to the main flare site sometimes only up to the time of the main impulsive phase, at which point the magnetic connection to the remote site may be broken and further flare manifestations are largely confined to the main flare site. This severing of the magnetic connection between two well-separated active regions may be an intrinsic part of the energy release in this flare.
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Bulletin of the American Astronomical Society, 34
© 2002. The American Astronomical Soceity.