Low-frequency wave instabilities in a plasma with a quasistatic electric field and weak spatial inhomogeneity

Abstract

A specific type of plasma-wave instability in a hot magnetoactive collisional plasma due to a weak external electric field and weak spatial inhomogeneity is considered for the cases of kinetic Alfvén-like waves. These low-frequency waves with ω [Lt ] Ωi (where Ωi is the ion gyrofrequency) are solutions of the corresponding dispersion relation. The model integral of Bhatnagar, Gross, and Krook is used for the description of collisions. The quasistatic time variation of the electric field amplitude makes it possible to use the ‘direct initiation’ mechanism to describe instability development. An expression for the growth rate is obtained in the framework of linear theory. The instability in question occurs for a certain equation of state of the plasma. For this equation of state, a numerical analysis of the obtained instabilities is performed.