Different Fokker–Planck approaches to simulate electron transport in plasmas

Abstract

An evaluation of different approximations of the Rosenbluth potentials is performed. A comparison is made between the Legendre expansion used in the FPI code with spherical Rosenbluth potentials, and an improved version (FPI+) with semi-anisotropic Rosenbluth potentials, and the new ( v, μ) Fokker–Planck code “FPTrans” with fully anisotropic Rosenbluth potentials, for the problem of the relaxation of a bi-Maxwellian ( T ⊥≠ T ∥) electron distribution function, which confirms the validity of the semi-anisotropic approximation, but not of the isotropic one. The improved code FPI+ was also used to compute new propagators for nonlocal electron heat transport.