Nonlinear Coupling of Electromagnetic and Electron Acoustic Waves in Multi-Species Degenerate Astrophysical Plasma

TL;DR

This paper investigates how nonlinear interactions between electromagnetic waves and electron-acoustic waves in a multi-species degenerate plasma can cause spectral shifts and form stable solitons, aiding interpretation of astrophysical observations.

Contribution

It introduces a model for nonlinear wave coupling in degenerate astrophysical plasma, revealing spectral shifts and soliton formation affecting observed radiation.

Findings

Electromagnetic waves can be spectrally downshifted through nonlinear interactions.

Stationary solitonic states of electromagnetic waves can form under certain conditions.

Modulated micro-pulses in radiation may serve as signatures of these nonlinear effects.

Abstract

Nonlinear wave--coupling is studied in a multi-species degenerate astrophysical plasma consisting of two electron species (at different temperatures): a highly degenerate main component plus a smaller classical relativistic flow immersed in a static neutralizing ion background. It is shown that the high frequency electromagnetic (HF EM) waves, through their strong nonlinear interactions with the electron--acoustic waves (sustained by a multi-electron component (degenerate) plasma surrounding a compact astrophysical object) can scatter to lower frequencies so that the radiation observed faraway will be spectrally shifted downwards. It is also shown that, under definite conditions, the EM waves could settle into stationary Solitonic states. It is expected that the effects of such structures may persist as detectable signatures in forms of modulated micro-pulses in the radiation observed far away from the accreting compact object. Both these effects will advance our abilities to interpret the radiation coming out of the compact objects.