Kink‐induced Catastrophe in a Coronal Eruption

Abstract

We investigate the kinking motion and its role in the eruption of a filament/cavity system that occurred on 2002 October 31. The evolution of the eruptive filament consists of four distinct phases. After an initial slow upward acceleration, the filament experiences a quasi-static phase exhibiting kinking motions of the filament axis. The kinking phase is followed by a sudden jump, coincident with the onset of the unkinking of the filament. The loss of equilibrium initiates a gradual relaxation phase at the end of which the filament reattains a similar unkinked configuration as its initial state. The filament/cavity structure, evident in the white-light observations, interacts with a large-scale coronal helmet streamer to the north, and material is observed to eject outward, aligned with a preexisting, low-density, dark channel that originally separated the northern helmet streamer from the southern streamer, where the dark cavity resides. The bulk of the filament, however, remains confined in the lower corona throughout the eruption along the channel. This suggests a partial eruption of the filament/cavity structure. The observations presented here manifest a catastrophic loss of equilibrium in response to the evolution of kinking motions in the filament activation.