Three-dimensional Dynamics of Strongly Magnetized Ion-Electron Relativistic Reconnection

TL;DR

This paper uses 3D simulations to explore relativistic magnetic reconnection with realistic mass ratios, revealing how 3D effects influence energy dissipation and particle acceleration in astrophysical environments.

Contribution

It provides the first large-scale 3D simulation study of semirelativistic reconnection with realistic mass ratios, highlighting the impact of 3D dynamics on reconnection efficiency.

Findings

3D effects significantly alter reconnection behavior at high magnetizations.

Magnetic energy dissipation and particle acceleration can be less efficient in 3D regimes.

Reconnection dynamics are strongly influenced by drift-kink and flux-rope kink instabilities.

Abstract

We present 3D simulations of semirelativistic collisionless magnetic reconnection, where upstream ions are subrelativistic while electrons are ultrarelativistic. We employ the realistic proton-to-electron mass ratio and explore a range of upstream ion magnetization spanning two orders of magnitude, with our highest-magnetization run achieving unprecedentedly large domain sizes. Through a parameter scan, we find that as the system transitions from mildly to trans- and ultrarelativistic regimes the qualitative behavior of reconnection becomes strongly influenced by 3D effects mediated by drift-kink and flux-rope kink dynamics. As a result, magnetic-energy dissipation at high magnetizations, and the subsequent nonthermal particle acceleration, can become less efficient, contrary to general expectations for 3D relativistic reconnection. Our results have important implications for understanding reconnection in magnetized astrophysical scenarios, such as the surroundings of black holes and neutron stars.