A 3D kinetic-fluid numerical code for stationary equilibrium states in magnetized plasmas

Abstract

In this paper we present a detailed description of a new stationary three-dimensional hybrid code with ions represented by particles and electrons by a massless fluid. We solve the ion equations of motion and ion distribution function moments are obtained. Conversely, we use a fluid approximation for the electrons. We determine the electron bulk velocity perpendicular to the magnetic field from the electron momentum equation with m e → 0 and without collisions. The parallel component of the electron bulk velocity is derived from the electron continuity equation. Once we have calculated the total current density, we determine the magnetic field from the Ampere's law, applying FFT algorithms, and from Faraday's law, we are able to calculate the components of the electric field. We use a recursive technique to obtain a self-consistent solution of our set of equations. We use this code to study how electrons influence the structure of the magnetotail current sheet in many physical processes as, for example, the formation of a double peak in the current density, which is observed very often by the CLUSTER spacecraft crossing of the neutral sheet.