Single-Mode Wave Decay

TL;DR

This paper demonstrates that a single-wave mode approach can effectively model electrostatic wave decay in beam-plasma systems, capturing key features traditionally attributed to separate Langmuir and ion-sound modes, especially under certain topological conditions.

Contribution

It introduces a feasible single-mode modeling approach for wave decay, supported by numerical solutions, that simplifies the analysis compared to the traditional two-mode method.

Findings

Single-mode approach captures both low and high frequency features.

Model aligns with two-wave approach in weak turbulence context.

Supports simplified analysis of wave decay processes.

Abstract

The usual approach on electrostatic wave decay process for a weak beam-plasma system considers two different wave modes interplaying, the Langmuir and ion-sound mode. In the present paper, a single-mode approach is shown to be feasible for conditions where the respective dispersion relations undergo topological changes. Numerical solutions for the dispersion relation of a beam-plasma system are presented, supporting the modeling of an analytic dispersion relation of a single wave mode. This wave mode is accounted for in the kinetic equations for particles and waves, which rule the evolution of the system. The results are compared against the two-wave mode approach using Langmuir and ion-sound waves, within the context of weak turbulence theory. It is found that the single-mode approach can account for the basic features of particles and waves, since the single mode exhibits both low and high frequency regions, which ultimately play the roles of ion-sound and Langmuir modes, respectively.