Fast collisionless reconnection and electron heating in strongly magnetized plasmas

TL;DR

This paper investigates magnetic reconnection in strongly magnetized, weakly collisional plasmas using a novel fluid-kinetic model, revealing electron Landau damping as the main dissipation mechanism and characterizing reconnection rates and island sizes.

Contribution

It introduces a new fluid-kinetic model that captures non-isothermal electron kinetics and provides detailed insights into electron heating and reconnection dynamics in low-beta plasmas.

Findings

Electron heating is dominated by Landau damping.

Reconnection rate peaks at approximately 0.2 times the Alfvén speed times magnetic field.

Island saturation width matches MHD predictions for large systems.

Abstract

Magnetic reconnection in strongly magnetized (low-beta), weakly collisional plasmas is investigated using a novel fluid-kinetic model [Zocco & Schekochihin, Phys. Plasmas 18, 102309 (2011)] which retains non-isothermal electron kinetics. It is shown that electron heating via Landau damping (linear phase mixing) is the dominant dissipation mechanism. In time, electron heating occurs after the peak of the reconnection rate; in space, it is concentrated along the separatrices of the magnetic island. For sufficiently large systems, the peak reconnection rate is $cE_{max}\approx 0.2v_AB_{y,0}$, where $v_A$ is the Alfv\'en speed based on the reconnecting field $B_{y,0}$. The island saturation width is the same as in MHD models except for small systems, when it becomes comparable to the kinetic scales.