Computer experiments on the relaxation of collisionless plasmas

Abstract

The relaxation of a collisionless plasma is not regulated by the usual collisional Boltzmann equation and itsrelated H-theorem. The interactions are long range and the collisions are not instantaneous. A directsimulation approach is presented for measuring by computer experiment what the relaxeddistribution is. The conclusion of the analysis is that the relaxed distribution includes botha low energy component that is well described using the usual Boltzmann distribution anda high energy tail described using a power law. The results of the simulation study arecompared directly with the model recently proposed by Kaniadakis (2002 Phys. Rev. E 66056125). The observed cumulative distribution function is well reproduced by thetheory.