Numerical simulation of oscillatory magnetic reconnection modulated by solar convective motions

TL;DR

This study uses 2.5D radiative MHD simulations to explore how solar convective motions modulate oscillatory magnetic reconnection, revealing quasi-periodic behavior and flow shifts consistent with observations.

Contribution

It demonstrates that external plasma and magnetic field emergence from the convection zone drive the oscillatory magnetic reconnection in the solar atmosphere.

Findings

Current sheet orientation reversed 41 times over 5771 s.

Reconnection rate oscillates with periods of 100-400 s.

Longest oscillation period observed is 30 minutes.

Abstract

Oscillatory magnetic reconnection is a periodic magnetic reconnection process, during which the current sheet's orientation and the magnetic connections change periodically. This periodic variation is generally considered to originate from the magnetic reconnection itself rather than from external driving processes. We conduct 2.5-dimensional radiative magnetohydrodynamic simulations to investigate the emergence of a magnetic flux tube from the convection zone into the lower corona, where the emerging magnetic fields reconnect with background ones. During the reconnection process within 5771 s, the current sheet's orientation has been reversed 41 times, corresponding to 40 oscillation periods. Notably, the longest period is 30 minutes, which is consistent with the previous observational results. We find that the main factor leading to the reversal of the current sheet's orientation is the quasi-periodic external force provided by the emergence of plasma and magnetic fields from the convection zone. We also find the shifting of the upward outflows from the reconnection region along the horizontal direction due to the alternating changes of the reconnection inflow and outflow regions. In addition to the quasi-periodic change of the current sheet orientation, the reconnection rate at the main X-point also oscillates with a period between 100-400 s, which corresponds to the period of p-mode oscillations.