A model of impulse-driven coupled hydromagnetic waves in the magnetosphere

Abstract

Hydromagnetic oscillations in the magnetosphere may be separated into two modes; toroidal oscillations (azimuthal field motions) and poloidal oscillations (radial motions). These modes are usually coupled, but the nature of the coupling has only been studied analytically in restricted geometries (e.g. one-dimensional uniform field models) or restricted regions (e.g. near the equatorial plane). Most workers have considered steady-state solutions. In this paper, preliminary numerical solutions of the coupled hydromagnetic wave equations in a cylindrical model magnetosphere, under the action of an impulse on the outer (magnetopause) boundary, are presented.