New version of drift approximation in inhomogeneous plasma kinetics

Plasma behaviour in a magnetic field is studied in a range of frequencies much lower than the electron cyclotron frequency and at wavelengths much longer than the Larmor radius of electrons. The study is aimed at deriving a system of bound equations for kinetic description of plasma motion, with a view to take into account the effect of an electric field on the motion of particles along the magnetic field. The method comprises using a well known drift approximation, whereby, instead of the motion of particles, the motion of their guiding centers is studied. The approximation is generalized for the case of a strong electric field, which changes the character of particle motion along the magnetic field. A system of kinetic equations has been derived along with an expression for current density, which permit consequent description of the plasma behaviour in weakly inhomogeneous and slowly changing electric and magnetic fields. The well known drift approximation equations adequately describe the motion of electrons and ions in the range of frequencies much lower than the ion cyclotron frequency. The derived system of equations can be used to describe plasma motions at a frequency close to and higher than the ion cyclotron frequency but much lower than the electron cyclotron one