System of Kinetic Equations for Collisionless Space Plasma in the Approximation of Field-Aligned Force Equilibrium for Electrons

Abstract

A system of kinetic equations describing relatively slow large-scale processes in collisionless magnetoplasma structures with a spatial resolution on the order of the proton thermal gyroradius is derived. The system correctly takes into account the electrostatic effects in the approximation of field-aligned force equilibrium for electrons. The plasma is considered quasineutral, and the magnetic field is described by the Ampère equation. The longitudinal component of the electric field is found explicitly from the equality of the field-aligned component of the electric force acting on plasma electrons and the divergence of the electron pressure tensor. The electric field component orthogonal to the magnetic field is determined by the distributions of the number densities, current densities, and stress tensors of all plasma species in the instantaneous long-range approximation described by a system of time-independent elliptic equations. Versions of the system of equations adapted to the case of magnetized electrons described by the Vlasov equation in the drift approximation, as well as to the case in which all plasma species are magnetized, are derived. The resulting systems of equations allow creating numerical models capable of describing large-scale processes in nonuniform collisionless space plasma.