Role of ion acoustic instability in magnetic reconnection

TL;DR

This study uses first-principles simulations to explore how ion acoustic instability influences magnetic reconnection, revealing it causes significant ion heating but minimal anomalous resistivity, thus affecting reconnection dynamics.

Contribution

It provides new insights into the role of ion acoustic instability in collisionless magnetic reconnection, especially regarding ion heating and resistivity effects.

Findings

Ion acoustic instability causes intense wave activity in the diffusion region.

The instability leads to substantial ion heating.

Anomalous resistivity contributions are minimal despite wave activity.

Abstract

We report on a first-principles numerical study of magnetic reconnection in plasmas with different initial ion-to-electron temperature ratios. In cases where this ratio is significantly below unity, we observe intense wave activity in the diffusion region, driven by the ion-acoustic instability. Our analysis shows that the dominant macroscopic effect of this instability is to drive substantial ion heating. In contrast to earlier studies reporting significant anomalous resistivity, we find that anomalous contributions due to the ion-acoustic instability are minimal. These results shed light on the dynamical impact of this instability on reconnection processes, offering new insights into the fundamental physics governing collisionless reconnection.