Nonlinear Landau damping and formation of BGK modes for plasmas with q-nonextensive velocity distributions

Abstract

We demonstrate using high resolution, long time simulations, the existence of BGK structures in 1D collisionless plasmas governed by non-extensive velocity distributions, namely q-distributions. We show that the BGK structures are supported only for certain range of q-values around q = 1 (Maxwellian). In particular, it is shown that for values of q < 1 where velocity distributions have long tails, strong Landau damping inhibits the formation of BGK structures while on the other limit of q > 1 where distribution has a sharp fall in velocity, the formation of BGK structures is rendered difficult due to high wave number damping imposed by the steep velocity profile. We compare our results with past work wherever relevant.