Dispersively formed quasi-periodic fast magnetosonic wavefronts due to the eruption of a nearby mini-filament

Abstract

Observational analysis is performed to study the excitation mechanism and propagation properties of a quasi-periodic fast-propagating (QFP) magnetosonic wave. The QFP wave was associated with the eruption of a nearby mini-filament and a small B4 Geostationary Operational Environmental Satellite (GOES) flare, which may indicate that the generation of a QFP wave does not require much flare energy. The propagation of the QFP wave was along a bundle of funnel-shaped open loops with a speed of about 1100 ± 78 km s-1 and an acceleration of -2.2 ± 1.1 kms-2. Periodicity analysis indicates that the periods of the QFP wave are 43 ± 6 and 79 ± 18 s. For the first time, we find that the periods of the QFP wave and the accompanying flare are inconsistent, which is different from the findings reported in previous studies. We propose that the present QFP wave was possibly caused by the mechanism of dispersive evolution of the initially broad-band disturbance resulting from the nearby mini-filament eruption.