Kinetic theory of current and density drift instabilities with weak charged‐neutral collisions

This paper describes the linear kinetic theory of electrostatic instabilities driven by a density gradient drift and a magnetic‐field‐aligned current in a plasma with weak charged neutral collisions. The configuration is that of a uniform magnetic field , a weak, uniform density gradient in the x direction and a weak, uniform electric field in the z direction. Collisions are represented by the BGK model. The transition from the (kinetic) universal density drift instability to the (fluidlike) current convective instability is studied in detail, and the short wavelength properties of the latter mode are investigated.