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arXiv · 1610.06137

Langmuir wave filamentation in the kinetic regime. I. Filamentation instability of Bernstein-Greene-Kruskal modes in multidimensional Vlasov simulations

Denis A. Silantyev·Pavel M. Lushnikov·Harvey A. Rose
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Abstract

A nonlinear Langmuir wave in the kinetic regime $k\lambda_D\gtrsim0.2$ may have a filamentation instability, where $k$ is the wavenumber and $\lambda_D$ is the Debye length. The nonlinear stage of that instability develops into the filamentation of Langmuir waves which in turn leads to the saturation of the stimulated Raman scattering in laser-plasma interaction experiments. Here we study the linear stage of the filamentation instability of the particular family \cite{RoseRussellPOP2001} of Bernstein-Greene-Kruskal (BGK) modes \cite{BernsteinGreeneKruskal1957} that is a bifurcation of the linear Langmuir wave. Performing direct $2+2D$ Vlasov-Poisson simulations of collisionless plasma we find the growth rates of oblique modes of the electric field as a function of BGK's amplitude, wavenumber and the angle of the oblique mode's wavevector relative to the BGK's wavevector. Simulation results are compared to theoretical predictions.

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Denis A. Silantyev, Pavel M. Lushnikov, Harvey A. Rose. 2016-10-19. Langmuir wave filamentation in the kinetic regime. I. Filamentation instability of Bernstein-Greene-Kruskal modes in multidimensional Vlasov simulations. https://doi.org/10.1063/1.4979289

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