Bernstein-wave instability in a collisional plasma with a quasistatic electric field

Abstract

Plasma-wave instability caused entirely by an external large-scale electric field E0 is considered for the pure electron Bernstein mode. It is assumed for the angle α between the wave vector k and the normal n to the direction of the external magnetic field B0 that the relation α≈tanα[Lt ]1 is fulfilled. The quasistatic time variation of the field E0, which is parallel to B0, provides the possibility of realizing the direct initiation (by the large-scale field E0) mechanism for the development of instability. An expression for the growth rate is obtained for the case when the external electric field E0 together with Landau damping and pair Coulomb collisions are taken into account in a modified dispersion relation (MDR). This expression is correct in the framework of linear theory for the frequency ranges typical of electron cyclotron waves and Bernstein modes. The influence of the electric field in the MDR is taken into account through the method of Brinca and Dysthe. A numerical analysis of obtained instability is performed for specific values of the plasma parameters.