Existence domains of arbitrary amplitude nonlinear structures in two-electron temperature space plasmas. II. High-frequency electron-acoustic solitons

TL;DR

This paper investigates the existence and amplitude limits of high-frequency electron-acoustic solitons in a three-component plasma with ions, cool electrons, and hot electrons, using Sagdeev potential formalism.

Contribution

It extends previous models by analyzing large amplitude solitons with and without hot electron inertia, revealing physical constraints on soliton amplitudes and potential types.

Findings

Negative potential solitons limited by density and double layer formation.

Positive potential solitons only exist with hot electron inertia.

Amplitude limits depend on Mach number and plasma parameters.

Abstract

A three-component plasma model composed of ions, cool electrons, and hot electrons is adopted to investigate the existence of large amplitude electron-acoustic solitons not only for the model for which inertia and pressure are retained for all plasma species which are assumed to be adiabatic but also neglecting inertial effects of the hot electrons. Using the Sagdeev potential formalism, the Mach number ranges supporting the existence of large amplitude electron-acoustic solitons are presented. The limitations on the attainable amplitudes of electron-acoustic solitons having negative potentials are attributed to a number of different physical reasons, such as the number density of either the cool electrons or hot electrons ceases to be real valued beyond the upper Mach number limit, or, alternatively, a negative potential double layer occurs. Electron-acoustic solitons having positive potentials are found to be supported only if inertial effects of the hot electrons are retained and these are found to be limited only by positive potential double layers.