Chaos-induced resistivity in different magnetic configurations

TL;DR

This study investigates how chaos-induced resistivity varies in different magnetic reconnection configurations, revealing it can be vastly higher than classical resistivity and depends on magnetic topology and magnetization.

Contribution

It provides the first detailed simulation-based analysis of chaos-induced resistivity across various magnetic configurations in reconnection current sheets.

Findings

Chaos-induced resistivity can be 6-7 orders of magnitude higher than classical resistivity.

Resistivity is significantly higher in X-type chaos regions compared to O-type regions.

Magnetization increases resistivity in X-type regions but has less effect in O-type regions.

Abstract

It is widely believed that magnetic reconnection plays an important role in various eruptive phenomena of space and astrophysical plasmas. The mechanism of anomalous resistivity, however, has been an open and unsolved problem. The chaos-induced resistivity proposed by Yoshida (1998) is one of possible mechanisms for anomalous resistivity. By use of the test particle simulation, the present work studies the chaos-induced resistivity for different configurations of reconnection magnetic fields and its distribution in different chaos regions of reconnection current sheets. The results show that the chaos-induced resistivity can be 6-7 orders of magnitude higher than the classical Spitzer resistivity in the X-type chaos regions and 5 orders of magnitude in the O-type chaos regions. Moreover, in the X-type chaos regions the chaos-induced resistivity of the magnetized case is higher by a factor of 2 to 3 times than that of the unmagnetized case, but in the O-type chaos regions the chaos-induced resistivity of the magnetized case is close to or lower than that of the unmagnetized case. The present work is helpful to the understanding of the dynamics of reconnection current sheets, especially of the generation mechanism of the anomalous resistivity of collisionless reconnection regions.