Enhanced acceleration of electrons populations by crossing electron cyclotron waves in an ambient magnetic field, Resonant Moments method Original Research Article

A mechanism for enhancing the acceleration of electrons by considering the effect of a low amplitude electron cyclotron waves crossing a primary wave in an ambient magnetic field is investigated. The underlying idea is that a low amplitude secondary wave may improve the transfer of parallel momentum from the high amplitude primary wave to charged particles. An analytical approximation, referred to as the Resonant Moments (RM) method, is proposed to estimate the efficiency of the wave configuration. Based on the RM method, optimal configurations are proposed for the two-wave scheme in which the secondary wave should be launched perpendicularly to the external magnetic field. Direct statistical (particle Monte Carlo) simulations confirm that such a configuration can yield an increase of the mean electron velocity of one order of magnitude when compared to the one-wave configuration. It is a quite promising result because the amplitude of the secondary wave is 10 times lower than the one of the first wave. The parameters used are related to electron acceleration in planetary magnetospheres, ionospheres as well in magnetic plasma fusion experiments.