Self-regulation of the reconnecting current layer in relativistic pair plasma reconnection

TL;DR

This paper studies how the reconnecting current layer in relativistic pair plasma self-regulates its thickness, maintaining fast reconnection rates, and explores conditions for current sheet expansion and the effects of guide fields.

Contribution

It introduces a self-regulation mechanism for the current layer thickness in relativistic reconnection and analyzes the impact of guide fields and incompressibility assumptions.

Findings

Current layer self-regulates thickness when current carriers are exhausted.

Relativistic reconnection maintains a fast reconnection rate.

Guide fields lead to more incompressible behavior and greater current sheet expansion.

Abstract

We investigate properties of the reconnecting current layer in relativistic pair plasma reconnection. We found that the current layer self-regulates its thickness when the current layer runs out current carriers, and so relativistic reconnection retains a fast reconnection rate. Constructing a steady state Sweet-Parker model, we discuss conditions for the current sheet expansion. Based on the energy argument, we conclude that the incompressible assumption is invalid in relativistic Sweet-Parker reconnection. The guide field cases are more incompressible than the anti-parallel cases, and we find a more significant current sheet expansion.