Alpha particle energy gain analysis for resonant wave-particle interactions in the heliosphere periphery

Abstract

Alpha particle resonant interactions with a single electromagnetic wave in homogeneous calm space plasma at the heliosphere periphery are studied. For this purpose, exact solutions of a second order nonlinear nonstationary differential equation for the wave phase on the alpha particle’s trajectory at the presence of weak constant magnetic field are obtained. Analyses are made for one set of the particle and wave initial parameters. The energy growth for an alpha particle with low initial energy surfatron acceleration is examined. Particle’s relativistic factor simulation results and its analytical approximation are shown and discussed. Estimations of the particle’s energy gain are given. Wave phase dynamics of the trapped alpha particle for the most interesting stages of the resonant interactions are presented in graphics. Conclusions about energy gain and the ability to generate ultrarelativistic alpha particles fluxes through the surfatron mechanism at the periphery of the heliosphere are made.