Nonlinear Ion-Acoustic Waves with Landau Damping in Non-Maxwellian Space Plasmas

TL;DR

This paper investigates how nonlinear ion-acoustic solitary waves evolve in space plasmas with non-Maxwellian electrons, incorporating Landau damping effects, and provides analytical and numerical insights into their amplitude decay and shock formation.

Contribution

It introduces a modified KdV equation with Landau damping for non-Maxwellian plasmas and derives exact solutions showing wave decay, advancing understanding of space plasma wave dynamics.

Findings

Solitary waves decay in amplitude due to Landau damping.

Non-Maxwellian electron distributions influence wave characteristics.

Numerical simulations highlight shock formation effects.

Abstract

The dynamics of nonlinear ion-acoustic solitary waves in the presence of kinetic (Landau type) damping have been investigated in a collisionless, non-magnetized electron-ion plasma. A cold ion fluid model, coupled to a Vlasov-type kinetic equation for the electron dynamics, has been adopted as a starting point. The electron population was assumed to be in a kappa-distributed state, in account of the non-Maxwellian behavior of energetic (suprathermal) electrons often observed in Space. A multiscale perturbation technique has led to an evolution equation for the electrostatic potential, in the form of a modified Korteweg-de Vries (KdV) equation, incorporating a non-local term accounting for Landau damping (associated with the electron statistics). Exact analytical solutions have been obtained, representing solitary waves undergoing amplitude decay over time. The combined effect of Landau damping and non-Maxwellian electron statistics (via the kappa parameter) on the characteristics of IASWs has been examined. Numerical integration of the evolution equation has been undertaken, to elucidate the importance of kinetic Landau damping on a shock-shaped initial condition. The results of this investigation aim to improve our understanding of the dynamics of nonlinear electrostatic waves under the influence of Landau damping in various space plasma environments.