Effect of the Magnetic Field on the Collision Frequencies between Charged and Neutral Particles

Abstract

The purpose of this paper is to show theoretically how much the magnetic field influences the collision frequencies between charged and neutral particles. First, the flow of charged particles crossing the cross section during time t is obtained, and then the collision frequency, F , in the magnetic field, B , is determined. Consequently, when 2π r L is small compared with the mean free path λ, it is shown that the contribution of the velocity component to the collision frequency is the velocity component due to the motion along the field axis and not that due to the gyration. Here, r L is the Larmor radius. When the velocity distribution function is isotropic, numerical results show that F in the magnetic field such that 2π r L ≪λ is half of that for B =0.