Study of Kappa-Distributions with and without Relativistic Cutoff

Linh Han Thanh

Within the framework of relativistic kinetic theory, a special relativistic generalization of isotropic
kappa distributions is proposed, based on the requirement that in the non-relativistic limit the
original distributions are recovered. By studying the moments, it is found that the relativistic
description of the standard kappa distribution leads to an even greater restriction on allowed kappa
values than in the non-relativistic case, whereas the relativistic regularized kappa distribution is able
to remove all divergences.