Magnetohydrodynamics of a weakly ionized plasma: Ambipolar magnetic diffusion and shock front structure

Kinetic equations with the BGK collision integral are used to derive MHD equations for a weakly ionized plasma that are applicable over a broad range of magnetic field strengths. In strong magnetic fields, a substantial contribution to the transverse diffusion of the magnetic field comes from the ambipolar magnetic diffusion, which is associated with the motion of both the charged component and the magnetic field against the background of the neutral plasma component. The problems of the magnetic field diffusion in a weakly ionized plasma and the shock wave structure are solved.