The Efficiency of Acceleration of Nonthermal Electrons with Whistler Turbulence in a Flare Loop Depending on Its Frequency Spectrum

This paper is devoted to the study of the interaction between nonthermal electrons injected into a flare loop and whistler turbulence in it. The features of redistributions of nonthermal electrons by energy and pitch angle are considered during their interaction with whistlers having spectra of different amplitudes, bandwidths, and central frequencies. We show, in particular, that this interaction results in an efficient and fast (seconds) acceleration of electrons in the energy range of 200–3000 keV, which leads to a significant flattening of their energy spectrum. The most efficient acceleration of high-energy electrons occurs by turbulence with low central frequencies, wide bandwidths, and large amplitudes. In this case, their concentration with energies above 1000 keV can increase by several orders of magnitude.