Fluid vs. kinetic magnetic reconnection with strong guide-fields

TL;DR

This paper demonstrates that magnetic reconnection rates in strong guide-field regimes are fast and independent of dissipation or system size, supported by detailed fluid and kinetic simulation comparisons.

Contribution

It provides a detailed derivation and simulation validation of the model showing fast reconnection in strong guide fields, challenging previous findings on the necessity of dispersive waves.

Findings

Reconnection rate is independent of collisional dissipation.

Reconnection rate is independent of system size.

Fluid and kinetic simulations show good agreement.

Abstract

The fast rates of magnetic reconnection found in both nature and experiments are important to understand theoretically. Recently, it was demonstrated that two-fluid magnetic reconnection remains fast in the strong guide field regime, regardless of the presence of fast-dispersive waves. This conclusion is in agreement with recent results from kinetic simulations, and is in contradiction to the findings in an earlier two-fluid study, where it was suggested that fast-dispersive waves are necessary for fast reconnection. In this paper, we give a more detailed derivation of the analytic model presented in a recent letter, and present additional simulation results to support the conclusions that the magnetic reconnection rate in this regime is independent of both collisional dissipation and system-size. In particular, we present a detailed comparison between fluid and kinetic simulations, finding good agreement in both the reconnection rate and overall length of the current layer. Finally, we revisit the earlier two-fluid study, which arrived at different conclusions, and suggest an alternative interpretation for the numerical results presented therein.