Spectral analysis of multidimensional current-driven plasma instabilities and turbulence in hollow cathode plumes

TL;DR

This study uses a 2D2V Vlasov--Poisson solver to analyze the growth, saturation, and turbulence of current-driven plasma instabilities in hollow cathode plumes, revealing detailed phase-space dynamics and ion behaviors.

Contribution

It introduces a comprehensive multidimensional kinetic simulation approach to understand plasma instability evolution and turbulence in hollow cathode environments.

Findings

Identification of four instability stages: linear growth, quasilinear resonance, nonlinear fill-in, and turbulence.

Generation of backstreaming ions following turbulent potential fields.

Insights into interscale phase-space transfer and plasma instability interactions.

Abstract

Large-amplitude current-driven instabilities in hollow cathode plumes can generate energetic ions responsible for cathode sputtering and spacecraft degradation. A 2D2V (two dimensions each in configuration [D] and velocity [V] spaces) grid-based Vlasov--Poisson (direct kinetic) solver is used to study their growth and saturation, which comprises four stages: linear growth, quasilinear resonance, nonlinear fill-in, and saturated turbulence. The linear modal growth rate, nonlinear saturation process, and ion velocity and energy distribution features in the turbulent regime are analyzed. Backstreaming ions are generated for large electron drifts, several ion acoustic periods after the potential field becomes turbulent. Interscale phase-space transfer and locality are analyzed for the Vlasov equation. The multidimensional study sheds light on the interactions between longitudinal and transverse plasma instabilities, as well as the inception of plasma turbulence.