Strong Magnetic Field Effects on the Collision Term and Electron-Ion Temperature Relaxation

Abstract

Under conditions when the particles’ thermal gyro-radii are smaller than the Debye length $$\lambda _D$$ , the magnetic field influence on the collision dynamics and associated transport processes becomes significant and has to be considered. In this paper, derivation of the kinetic equation based on the Fokker–Planck approach is reviewed for uniform magnetized plasmas with $$\rho _{the}<\lambda _D<\rho _{thi}$$ , where $$\rho _{the}$$ and $$\rho _{thi}$$ are the electron and ion thermal gyro-radii, respectively. Generally speaking, current tokamak plasmas lie in the above studied parameter range. Serving as an example for the application of the derived magnetized kinetic equation and demonstrating the modifications to the transport coefficients from a strong magnetic field, the electron-ion temperature relaxation is reviewed. The relaxation time exhibits a noticeable magnetic field dependence.