Eruption of Solar Magnetic Flux Ropes Caused by Flux Feeding

TL;DR

This study uses 2.5D MHD simulations to show that flux feeding from emerging small flux ropes can build up a solar flux rope to trigger eruptions, clarifying the eruption mechanism.

Contribution

It demonstrates through simulations that flux feeding can cause solar flux rope eruptions by increasing axial flux to a critical level.

Findings

Discrete flux rope emergence can trigger eruptions.

Flux feeding increases axial flux until eruption threshold.

Eruption onset is dominated by ideal MHD processes.

Abstract

Large-scale solar eruptions are believed to have a magnetic flux rope as the core structure. However, it remains elusive as to how the flux rope builds up and what triggers its eruption. Recent observations found that a prominence erupted following multiple episodes of "flux feeding". During each episode, a chromospheric fibril rose and merged with the prominence lying above. In this letter, we carried out 2.5-dimensional magnetohydrodynamic (MHD) numerical simulations to investigate whether the flux-feeding mechanism can explain such an eruption. The simulations demonstrate that the discrete emergence of small flux ropes can initiate eruptions by feeding axial flux into the preexistent flux rope until its total axial flux reaches a critical value. The onset of the eruption is dominated by an ideal MHD process. Our simulation results corroborate that the flux feeding is a viable mechanism to cause the eruption of solar magnetic flux ropes.