Oscillations and mass-draining that lead to a sympathetic eruption of a quiescent filament

Abstract

In this paper, we present a multi-wavelength analysis to mass-draining and oscillations in a large quiescent filament prior to its successful eruption on 2015 April 28. The eruption of a smaller filament that was parallel and in close, ∼350 proximity was observed to induce longitudinal oscillations and enhance mass-draining within the filament of interest. The longitudinal oscillation with an amplitude of ∼25 Mm and ∼23 km s −1 underwent no damping during its observable cycle. Subsequently the slightly enhanced draining may have excited a eruption behind the limb, leading to a feedback that further enhanced the draining and induced simultaneous oscillations within the filament of interest. We find significant damping for these simultaneous oscillations, where the transverse oscillations proceeded with the amplitudes of ∼15 Mm and ∼14 km s −1 , while the longitudinal oscillations involved a larger displacement and velocity amplitude (∼57 Mm, ∼43 km s −1 ). The second grouping of oscillations lasted for ∼2 cycles and had the similar period of ∼2 hours. From this, the curvature radius and transverse magnetic field strength of the magnetic dips supporting the filaments can be estimated to be ∼355 Mm and ≥34 G. The mass-draining within the filament of interest lasted for ∼14 hours. The apparent velocity grew from ∼35 km s −1 to ∼85 km s −1 , with the transition being coincident with the occurrence of the oscillations. We conclude that two filament eruptions are sympathetic, i.e. the eruption of the quiescent filament was triggered by the eruption of the nearby smaller filament.