Nonlinear separate spin evolution in degenerate electron-positron-ion plasmas

TL;DR

This paper investigates the nonlinear behavior of various acoustic waves in degenerate electron-positron-ion plasmas, demonstrating the formation of three types of solitons, including first-time reports of certain solitons in this plasma context.

Contribution

It introduces the first description of spin-electron-positron acoustic solitons and explores their properties in degenerate electron-positron-ion plasmas.

Findings

Existence of three different solitons in the plasma.

First report of spin-electron-positron acoustic solitons.

Behavior of solitons depends on positron imbalance.

Abstract

The non-linear evolution of spin-electron acoustic, positron-acoustic, and spin-electron-positron acoustic waves is considered. It is demonstrated that weakly nonlinear dynamics of each wave leads to the soliton formation. Altogether, we report on existence of three different solitons. The spin-electron acoustic soliton known for electron-ion plasmas is described for electron-positron-ion plasmas for the first time. The existence of the spin-electron-positron acoustic soliton is reported for the first time. The positron-acoustic soliton and the spin-electron-positron acoustic soliton arise as the areas of a positive electric potential. The spin-electron acoustic soliton behaves as the area of a negative electric potential at the relatively small positron imbalance $n_{0p}/n_{0e}=0.1$ and as the area of a positive electric potential at the relatively large positron imbalance $n_{0p}/n_{0e}=0.5$.