Two Episodes of a Filament Eruption from a Fan-spine Magnetic Configuration

Abstract

Abstract In this paper, we present detailed observations of a filament eruption associated with a B6.0 flare, a jet-like coronal mass ejection (CME), and a type-III radio burst on 2013 March 2. The filament, which is located at the northwest edge of active region (AR) 11183, experienced a partial and then a full eruption. Each episode of the filament eruption produced a circular flare ribbon and a blowout jet, which is a mixture of hot and cool plasma that can be observed by the Solar Dynamics Observatory. Extrapolated coronal magnetic configuration using both the potential field source surface and the nonlinear force-free magnetic field models shows that the filament is embedded in a fan-spine magnetic topology. Considering the photospheric magnetic evolution, we suggest that the first episode of the filament eruption (partial eruption) is caused by the continuous photospheric magnetic flux cancellation below its western segment, while the eruption that follows results from the reduction of magnetic constraint above the filament in the aftermath of the first eruption episode and reconnection. Combining the observations with the extrapolated coronal magnetic configuration, we find that the event is an example that fits the null-point reconnection scenario. Our event is a result of null-point reconnection (interchange reconnection) between a closed filament magnetic field and the ambient open field at the edge of an AR, thus it has implications for the source of the slow speed solar wind and the source of the cold and dense plasma detected within.