Observations of Photospheric Vortical Motions During the Early Stage of Filament Eruption

TL;DR

This study observed photospheric vortical motions near filament ends during early eruption phases, suggesting these motions may destabilize filaments by increasing magnetic pressure, potentially triggering eruptions.

Contribution

It provides new observational evidence linking photospheric vortical motions to filament destabilization and eruption mechanisms.

Findings

Photospheric vortical motions last 4-20 minutes.

Opposite rotation directions at filament ends in most cases.

Vortical motions may contribute to filament eruption by increasing magnetic pressure.

Abstract

Solar filaments/prominences exhibit rotational motion during different phases of their evolution from their formation to eruption. We have observed the rotational/vortical motion in the photosphere near the ends of ten filaments during their initial phase of eruption, at the onset of the fast rise phase. All the filaments were associated with active regions. The photospheric vortical motions we observed lasted for 4--20 minutes. In the vicinity of the conjugate ends of the filament the direction of rotation was opposite, except for two cases, where rotational motion was observed at only one end point. The sudden onset of a large photospheric vortex motion could have played a role in destabilizing the filament by transporting axial flux into the activated filament thereby increasing the outward magnetic pressure in it. The outward magnetic pressure may have pushed the filament/flux rope to the height where the torus instability criterion was satisfied, and hence it could have caused the filament instability and eruption.