Particle acceleration in solar flares at different frequencies

The multifrequency analysis of solar flares is necessary due to the great complexity it presents. We present the investigation of thirteen solar flares that occurred between 2011 and 2013, studied in radio from 5 to 212 GHz (RSTN, POEMAS, SST), and in X-rays up to 800 keV (FERMI and RHESSI). The goal of this work is to determine the population of accelerated electrons by studing the spectral index in radio and hard X-rays (HXR). Previous works have shown that the temporal profiles at both wavelengths are very similar which is indicative of a common accelerated electron population. In this work, the radio spectral index was calculated by fitting the radio spectra by gyrosynchrotron emission, whereas the hard X-ray spectra were fit by thermal emission plus non-thermal emission from accelerated electron with a power-law distribution, yielding the HXR spectral index. Finally, we compare the results of both spectral indices and discuss the results in light of the models of particle acceleration.