Langevin representation of Coulomb collisions for bi-Maxwellian plasmas
Langevin model corresponding to the FokkerPlanck equation for bi-Maxwellian particle distribution functions is developed. Rosenbluth potentials and their derivatives are derived in the form of triple hypergeometric functions. The Langevin model is tested in the case of relaxation of the proton temperature anisotropy and implemented into the hybrid expanding box model. First results of this code are presented and discussed.
coulomb collisions langevin equation bi-maxwellian distribution function stochastic differential equation