Eruption of magnetic flux ropes during flux emergence

TL;DR

This study uses 3D MHD simulations to explore how magnetic flux ropes form and erupt during solar flux emergence, revealing the conditions that lead to eruptions like CMEs.

Contribution

It demonstrates the formation and eruption mechanisms of flux ropes during flux emergence using detailed numerical experiments.

Findings

Flux ropes form via shearing and reconnection during flux emergence.

Eruptions occur when the flux rope reconnects with preexisting coronal fields.

Reconnection with ambient fields leads to full eruptions resembling CMEs.

Abstract

Aims: We investigate the formation of flux ropes in a flux emergence region and their rise into the outer atmosphere of the Sun. Methods: We perform 3D numerical experiments solving the time-dependent and resistive MHD equations. Results: A sub-photospheric twisted flux tube rises from the solar interior and expands into the corona. A flux rope is formed within the expanding field, due to shearing and reconnection of field lines at low atmospheric heights. If the tube emerges into a non-magnetized atmosphere, the flux rope rises, but remains confined inside the expanding magnetized volume. On the contrary, if the expanding tube is allowed to reconnect with a preexisting coronal field, the flux rope experiences a full eruption with a rise profile which is in qualitative agreement with erupting filaments and Coronal Mass Ejections.