Nonlinear electronic streaming instability in lunar plasmas

Abstract

The nonlinear dynamics of bi-electronic streaming instability (BSI) is investigated in lunar plasma environments using the nonlinear WKB method. It is seen that the considered instability saturation is governed by a standard form of the Korteweg-de Vries (KdV) equation. It has a unique set of multiparametric nonlinear convective and linear dispersive coefficients. We semi-analytically reveal the instability saturation, principally in diverse solitary wave forms, alongside their basic conservation laws, in a broader perspective horizon. The sensitive frame velocity-dependency of the derived rarefactive solitary structures is illustrated, alongside the streaming velocity effects. It is interestingly found that such wave-spectral patterns completely disappear for a particular value of the relative streaming velocity (frame-flow equalisation). This study fairly maps the investigated nonlinear BSI saturation amongst the Kaguya-observed electrostatic solitary waves (ESWs) observationally reported elsewhere.