Acoustic Kappa-Density Fluctuation Waves in Suprathermal Kappa Function Fluids

TL;DR

This paper introduces a novel wave mode in plasmas with suprathermal kappa distributions, characterized by coupled density and velocity fluctuations, which propagates faster than traditional acoustic waves and reduces to them in the Maxwellian limit.

Contribution

It presents the discovery of a new wave mode in suprathermal plasma distributions involving fluctuations in the kappa index, expanding understanding of plasma wave phenomena.

Findings

The new wave mode propagates faster than traditional acoustic waves.

It reduces to the classical acoustic wave as kappa approaches infinity.

The wave involves simultaneous fluctuations in density, velocity, and the kappa index.

Abstract

We describe a new wave mode similar to the acoustic wave in which both density and velocity fluctuate. Unlike the acoustic wave in which the underlying distribution is Maxwellian, this new wave mode occurs when the underlying distribution is a suprathermal kappa function and involves fluctuations in the power law index, kappa. This wave mode always propagates faster than the acoustic wave with an equivalent effective temperature and becomes the acoustic wave in the Maxwellian limit as kappa goes to infinity.