Nonlinear coupling of whistler waves to oblique electrostatic turbulence enabled by cold plasma

TL;DR

This paper shows that cold plasma populations can enable whistler waves to excite oblique turbulence through secondary instabilities, affecting wave amplitudes and plasma heating in Earth's magnetosphere.

Contribution

It introduces a new mechanism for nonlinear coupling between whistler waves and electrostatic turbulence via cold plasma-induced secondary drift instabilities.

Findings

Whistler waves can excite oblique fluctuations in cold plasma environments.

Cold plasma populations lead to wave damping and plasma heating.

The instability threshold depends on cold plasma density and temperature.

Abstract

Kinetic simulations and theory demonstrate that whistler waves can excite oblique, short-wavelength fluctuations through secondary drift instabilities if a population of sufficiently cold plasma is present. The excited modes lead to heating of the cold populations and damping of the primary whistler waves. The instability threshold depends on the density and temperature of the cold population and can be relatively small if the temperature of the cold population is sufficiently low. This mechanism may thus play a significant role in controlling amplitude of whistlers in the regions of the Earth's magnetosphere where cold background plasma of sufficient density is present.