The Effect of Magnetic Reconnection and Writhing in a Partial Filament Eruption
Abstract
We present observations from 2007 March 2 of a partial filament eruption characterized by two distinct phases of writhing motions: a quasi-static, slowly evolving phase followed by a rapid kinking phase showing a bifurcation of the filament. The quasi-static kinking motions are observed before there is any heating or flaring evident in EUV or soft X-ray (SXR) observations. As the writhe of the filament develops, a sigmoid becomes sharply defined in the SXR. Prior to eruption onset, the sigmoid in the EUV appears to be composed of two separate looplike structures, which are discontinuous at the projected location where the sigmoid crosses the filament. Coincident with the onset of the eruption and the production of a GOES class B2 flare, the original "two-loop" EUV sigmoid is now observed as a single continuous structure lying above the filament, signifying the presence of magnetic reconnection and the associated dissipative heating of field lines above the filament. During the eruption, the escaping portion of the filament rotates quickly and erupts together with the expanding arched sigmoid. The portion of the filament that is left behind develops into an inverse S-shaped configuration. The separation of the filament, the EUV brightening at the separation location, and the surviving sigmoidal structure are all signatures of magnetic reconnection occurring within the body of the original filament. Other features of the same event reported by Sterling and coworkers, e.g., the flux cancellation at the polarity inversion line prior to the eruption and the SXR compact loop formed underneath the erupting sigmoid during the eruption, indicate that magnetic reconnection also occurred in the sheared core field beneath the filament. These results suggest that a combination of the kinking motions and internal tether-cutting are responsible for the initiation of the eruption.
- Publication:
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The Astrophysical Journal
- Pub Date:
- June 2008
- DOI:
- 10.1086/587482
- Bibcode:
- 2008ApJ...680.1508L
- Keywords:
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- Sun: corona;
- Sun: filaments