Dynamics of braided coronal loops - I. Onset of magnetic reconnection

TL;DR

This study uses resistive MHD simulations to investigate how small-scale boundary motions in the solar corona can lead to current sheet formation and magnetic reconnection in braided magnetic fields, revealing 3D reconnection features.

Contribution

It provides a detailed numerical analysis of the onset of magnetic reconnection in braided coronal loops, highlighting 3D structures and dynamics not previously well-characterized.

Findings

Formation of thin current sheets via instability

Magnetic reconnection occurs across current sheets

Global field untwisting observed after reconnection

Abstract

The response of the solar coronal magnetic field to small-scale photospheric boundary motions including the possible formation of current sheets via the Parker scenario is one of open questions of solar physics. Here we address the problem via a numerical simulation. The three-dimensional evolution of a braided magnetic field which is initially close to a force-free state is followed using a resistive MHD code. A long-wavelength instability takes place and leads to the formation of two thin current layers. Magnetic reconnection occurs across the current sheets with three-dimensional features shown, including an elliptic magnetic field structure about the reconnection site, and results in an untwisting of the global field structure.