Solar flare radio and hard X-ray observations and the avalanche model

Abstract

This paper reviews hard X-ray and radio observations obtained with high temporal and/or spatial resolution which show that the production of non thermal electrons is fragmented in both space and time. Observations dealing with the extent in heights and spatial scales of the electron acceleration sites are also reviewed. The knowledge of the electron energy spectra deduced at low and high energies from both hard X-ray and centimeter/millimeter observations is discussed. The experimental data is compared with the predictions of the avalanche model for solar flares and further tests of the model proposed.