Unambiguous Evidence of Filament Splitting-Induced Partial Eruptions

TL;DR

This study provides clear observational evidence that filament splitting within magnetic flux ropes can cause partial solar eruptions, involving internal reconnection and resulting in distinct eruption outcomes.

Contribution

It is the first to directly observe filament splitting-induced partial eruptions and elucidate the internal reconnection process involved.

Findings

Partial eruptions involve vertical filament splitting with internal reconnection.

Both confined and successful eruptions produce flare signatures and X-ray sources.

Extended bald-patch sections are confirmed in successful eruptions.

Abstract

Coronal mass ejections are often considered to result from the full eruption of a magnetic flux rope (MFR). However, it is recognized that, in some events, the MFR may release only part of its flux, with the details of the implied splitting not completely established due to limitations in observations. Here, we investigate two partial eruption events including a confined and a successful one. Both partial eruptions are a consequence of the vertical splitting of a filament-hosting MFR involving internal reconnection. A loss of equilibrium in the rising part of the magnetic flux is suggested by the impulsive onset of both events and by the delayed onset of reconnection in the confined event. The remaining part of the flux might be line-tied to the photosphere in a bald patch separatrix surface, and we confirm the existence of extended bald-patch sections for the successful eruption. The internal reconnection is signified by brightenings in the body of one filament and between the rising and remaining parts of both filaments. It evolves quickly into the standard current sheet reconnection in the wake of the eruption. As a result, regardless of being confined or successful, both eruptions produce hard X-ray sources and flare loops below the erupting but above the surviving flux, as well as a pair of flare ribbons enclosing the latter.