Particle acceleration in complex magnetic field configurations: what can be observed/what should be attempted to be observed by radio techniques ?

Loukas Vlahos

The standard model used so far for the energy release, particle acceleration and radio emission is based on the following components: (1) The formation of a current sheet above a magnetic loop, (2) The stochastic acceleration of particle in 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 them assuming that a complex active region driven by the photospheric motions, forms stochastically current sheets and accelerate particles trapped on stochastic filed lines. The emphasis will be placed on the efficiency and the observational tests of the two alternatives.