To description of motion of rarefied magnetospheric plasma in a strong magnetic field

The theoretical models used to describe of dynamic processes in the planet's magnetosphere are analysed. A completely ionized plasma of small density in the strong magnetic field, consisting of electrons and ions of one kind is considered. The various aspects of modeling related as with the free motion of individual charged particles in the external field in approximation of leading center and considering collective properties of the magnetospheric plasma are discussed. The kinetic approach is based on solution the system of equations of Vlasov with self-consistent electromagnetic fields for ions. The method of obtaining a set of hydrodynamic equations for the motion of a rarefied plasma across the magnetic field and an approximate kinetic equation for the sake of longitudinal motion is substantiated. Small parameter of approximation is the relation of the characteristic frequency of dynamic processes in plasma to the cyclotron frequency of ions. In the case of a certain symmetry of the distribution function with respect to longitudinal velocities (owing to which there are no heat flows along the lines of force) and proceeding from the system of kinetic equations in the drift approximation, are derived the equations of two-fluid hydrodynamics , intended for describing slow motions of a plasma with an anisotropic pressure tensor.