The role of particle feedback on particle acceleration in magnetic reconnection

TL;DR

This study uses advanced simulations to show that particle feedback enhances magnetic reconnection and particle acceleration by amplifying shear flows, with guide fields suppressing these effects, revealing complex plasma interactions.

Contribution

It introduces a co-evolving fluid-particle simulation framework to analyze feedback effects on reconnection and acceleration, highlighting the role of shear flows and guide fields.

Findings

Particle feedback amplifies shear flows within magnetic islands.

Enhanced shear flows strengthen the electric field, boosting particle acceleration.

Guide fields suppress internal energy increase and particle acceleration.

Abstract

Magnetic reconnection is a ubiquitous process in astrophysical plasmas and an efficient mechanism for particle acceleration. Using 2.5D magnetohydrodynamic (MHD) simulations with a co-evolving fluid-particle framework, we investigate how particle feedback affects reconnection and acceleration. Our simulations demonstrate that particle feedback to the fluid amplifies shear flows within magnetic islands, which strengthens the convective electric field and thereby boosts particle acceleration. This mechanism results in a higher maximum particle energy and a harder non-thermal energy spectrum. The guide field suppresses both the increase in gas internal energy and particle acceleration. These findings highlight the complex interplay between feedback, guide fields, and reconnection dynamics.