Three-Dimensional MHD Magnetic Reconnection Simulations with Finite Guide Field: Proposal of the Shock-Evoking Positive-Feedback Model

TL;DR

This paper introduces a 3D MHD simulation model demonstrating that interactions between multiple tearing layers in a current sheet create a positive-feedback system, significantly enhancing magnetic reconnection rates compared to classical models.

Contribution

The study proposes the shock-evoking positive-feedback model, revealing how 3D interactions and slow-mode shocks accelerate magnetic reconnection beyond traditional 2D or single-perturbation models.

Findings

Enhanced reconnection rate compared to Sweet-Parker model

Formation of flux tubes and slow-mode shocks

Positive-feedback system absent in 2D or single-mode reconnection

Abstract

Using a three-dimensional magnetohydrodynamic model, we simulate the magnetic reconnection in a single current sheet. We assume a finite guide field, a random perturbation on the velocity field and uniform resistivity. Our model enhances the reconnection rate relative to the classical Sweet-Parker model in the same configuration. The efficiency of magnetic energy conversion is increased by interactions between the multiple tearing layers coexisting in the global current sheet. This interaction, which forms a positive-feedback system, arises from coupling of the inflow and outflow regions in different layers across the current sheet. The coupling accelerates the elementary reconnection events, thereby enhancing the global reconnection rate. The reconnection establishes flux tubes along each tearing layer. Slow-mode shocks gradually form along the outer boundaries of these tubes, further accelerating the magnetic energy conversion.Such positive-feedback system is absent in two-dimensional simulation, three-dimensional reconnection without a guide field and a reconnection under a single perturbation mode. We refer to our model as the "shock-evoking positive-feedback" model.