A fundamental mechanism of solar eruption initiation

TL;DR

This paper demonstrates through high-accuracy 3D magnetohydrodynamic simulations that solar eruptions can originate from simple bipolar magnetic configurations without special topologies, driven by photospheric shearing and magnetic reconnection.

Contribution

It reveals a fundamental eruption initiation mechanism that does not require complex magnetic topologies, challenging previous theories.

Findings

Eruption initiated in a bipolar configuration without special topology.

Photospheric shearing leads to current sheet formation and reconnection.

Eruption results in a fast-expanding twisted flux rope.

Abstract

Solar eruptions are spectacular magnetic explosions in the Sun's corona, and how they are initiated remains unclear. Prevailing theories often rely on special magnetic topologies that may not generally exist in the pre-eruption source region of corona. Here, using fully three-dimensional magnetohydrodynamic simulations with high accuracy, we show that solar eruptions can be initiated in a single bipolar configuration with no additional special topology. Through photospheric shearing motion alone, an electric current sheet forms in the highly sheared core field of the magnetic arcade during its quasi-static evolution. Once magnetic reconnection sets in, the whole arcade is expelled impulsively, forming a fast-expanding twisted flux rope with a highly turbulent reconnecting region underneath. The simplicity and efficacy of this scenario argue strongly for its fundamental importance in the initiation of solar eruptions.