Theory for Finite Temperature Effects on Magnetosonic Waves in a Two-Ion-Species Plasma

Abstract

The theory of magnetosonic waves perpendicular to a magnetic field in a two-ion-species plasma is extended to include finite temperature effects based on the three-fluid model with finite ion and electron pressures. First, the condition for the dispersion relation of the low-frequency mode, the lower branch of magnetosonic waves, to be approximated as a form of weak dispersion is presented. Next, by virtue of this, it is shown that the KdV equation for the low-frequency mode is valid for amplitude ε < ε_max, where the upper limit of the amplitude ε_max is given as a function of the ratio of the kinetic to magnetic energies, the density ratio, and the cyclotron frequency ratio of two ion species. The finite-temperature effects on linear and nonlinear high-frequency modes and on heavy-ion acceleration by the high-frequency-mode pulse are also discussed.