Electron heating in a current-driven turbulence as a result of nonlinear interaction of electron- and ion-acoustic waves

TL;DR

This paper investigates how nonlinear interactions between electron- and ion-acoustic waves in collisionless turbulence lead to significant electron heating, highlighting the role of giant electron holes and phase mixing.

Contribution

It demonstrates through PIC simulations that large-amplitude ion-acoustic waves and electron holes are key to electron heating in current-driven turbulence, revealing new insights into nonlinear wave interactions.

Findings

Large-amplitude ion-acoustic waves excite electron holes.

Giant electron holes cause strong electron heating.

Simulation results align with previous observations.

Abstract

We study electron heating in collisionless current-driven turbulence due to the nonlinear interactions between electron- and ion-acoustic waves. PIC simulation results show that due to a large difference between the electron and ion mean velocities the Buneman instability excites large-amplitude ion-acoustic waves, which strongly modifies the electron velocity distribution function, leading to a secondary instability that generates fast electron-acoustic waves; and in this process, a giant electron hole is ultimately created. This giant electron hole is responsible for strong electron heating due to phase mixing. The numerical simulation results are consistent with the previous observations and provide insight into the key processes responsible for electron heating and the generation of nonlinear waves in a collisionless current-driven instability.