The propagation of high‐m Alfvén waves in the Earth's magnetosphere and their interaction with high‐energy particles

Abstract

This paper is devoted to the study of Alfvén waves generated by the bounce‐drift resonance. The global structure of such waves is investigated with due regard to the curvature of field lines, the plasma nonuniformity along field lines and across magnetic shells, finite plasma pressure, and the interaction of the waves with the ionosphere. It is shown that the wave is enhanced as it propagates across magnetic shells with a growth rate dependent on the radial coordinate: The growth rate is maximal on the poloidal surface (i.e., on the magnetic shell, on which the oscillations have a poloidal character), and it decreases to zero on the toroidal surface (where the oscillations have a toroidal character). However, the amplitude maximum does not coincide with the poloidal surface; it is shifted toward the toroidal surface. Moreover, when the value of the growth rate due to the driving particles increases on the poloidal surface, the amplitude maximum of the wave is shifted toward the toroidal surface.