Motion of charged particles in the field of a monochromatic wave in the Earth's magnetospheric tail

Perturbation theory is used to study the motion of charged particles in the field of an electromagnetic or electrostatic low-frequency monochromatic wave in the region of reversed magnetic field in the Earth's magnetospheric tail. The influence of resonant processes on particle dynamics is described. The time scale on which the particle motion becomes stochastic is estimated for different parameters of the wave. The parameter range is determined for which resonant effects dominate over the effect of repeated crossings of a separatrix.