Low-frequency wave instabilities in magnetoactive plasma with spatial inhomogeneity of temperature

Abstract

The dispersion relation (DR) has been considered for low-frequency waves in a hot magnetoactive collisional plasma with 'longitudinal' large-scale electric field E 0 (t) and weak spatial inhomogeneity of temperature. The electric field was assumed to be extremely weak ('subdriecer' field) and the quasi-static time variation of its amplitude allows us to use the 'direct initiation' mechanism to describe the instability development. Taking into account the ion thermal motion has not changed the form of the DR. which has remained the polynomial of the fourth order, hut it has essentially complicated the form of its coefficients. As compared with previous investigations, these changes have resulted in the changes of the solutions of the DR. Two of the roots of the DR have remained of the same type ('kinetic Alfven-like waves), but another two have become quite different and get to the range of slow magneto-acoustic waves. Investigation of these new waves has shown that corresponding instability has clearly expressed threshold character, and the value of this threshold depends essentially on the reduced value of the electric field amplitude E 0 (t) and ratio of electron and ion temperatures.