Asymmetric eruptive filaments

Abstract

Filaments are often observed to erupt asymmetrically, during which one leg is fixed to the photosphere (referred to as the anchored leg) while the other undertakes most of the dynamic motions (referred to as the active leg) during the eruptive process. In this paper, we present observations of a group of asymmetric eruptive filaments, in which two types of eruptions are identified: whipping-like, where the active leg whips upward, and hard X-ray sources shift toward the end of the anchored leg; and zipping-like, where the visible end of the active leg moves along the neutral line like the unfastening of a zipper as the filament arch rises and expands. During a zipping-like eruption, hard X-ray sources shift away from where the eruption initiates toward where the visible end of the active leg eventually stops moving. Both types of asymmetric eruptions can be understood in terms of how the highly sheared filament channel field, traced by filament material, responds to an external asymmetric magnetic confinement, where force imbalance occurs in the neighborhood of the visible end of the active leg. The dynamic motions of the active leg have a distinct impact on how hard X-ray sources shift, as observed by RHESSI. © 2009. The American Astronomical Society. All rights reserved..