Magnetic complexity, fragmentation, particle acceleration and radio emission from the sun

Abstract

The most popular flare model used to explain the energy release, particle acceleration and radio emission is based on the following assumptions: (1) The formation of a current sheet above a magnetic loop, (2) The stochastic acceleration of particles in the current sheet at the helmet of the loop, (3) the transport and trapping of particles inside the flaring loop. We review the observational consequences of the above model and try to generalize by putting forward a new suggestion, namely assuming that a complex active region driven by the photospheric motions forms naturally a large number of stochastic current sheets that accelerate particles, which in turn can be trapped or move along complex field line structures. The emphasis will be placed on the efficiency and the observational tests of the different models proposed for a flare. © 2007 Springer.