Quasi-perpendicular magnetosonic waves in a multi-ion-species plasma

Propagation of oblique magnetosonic waves in a multi-ion-species plasma is studied with theory and three-fluid simulations. First, the linear dispersion relation of the high-frequency mode, the upper branch of magnetosonic waves, is examined in detail. Next, nonlinear evolution equation for this mode is derived. This mode can propagate as compressive or rarefactive solitary pulses, depending on the propagation angle. Ion acceleration due to these pulses and resultant pulse damping are analytically discussed. These processes are then demonstrated by fluid simulations for a plasma consisting of H, He, and electrons; either rarefactive or compressive pulses are gradually damped owing to the slight ion acceleration. (C) 2003 American Institute of Physics.