RHESSI and TRACE Observations of Multiple Flare Activity in AR 10656 and Associated Filament Eruption
Abstract
We present Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) and Transition Region and Coronal Explorer (TRACE) observations of multiple flare activity that occurred in the NOAA active region 10656 over a period of 2 hr on 2004 August 18. Out of four successive flares, three were class C events, and the final event was a major X1.8 solar eruptive flare. The activities during the pre-eruption phase, i.e., before the X1.8 flare, are characterized by three localized episodes of energy release occurring in the vicinity of a filament that produces intense heating along with non-thermal emission. A few minutes before the eruption, the filament undergoes an activation phase during which it slowly rises with a speed of ~12 km s-1. The filament eruption is accompanied by an X1.8 flare, during which multiple hard X-ray (HXR) bursts are observed up to 100-300 keV energies. We observe a bright and elongated coronal structure simultaneously in E(UV) and 50-100 keV HXR images underneath the expanding filament during the period of HXR bursts, which provides strong evidence for ongoing magnetic reconnection. This phase is accompanied by very high plasma temperatures of ~31 MK, followed by the detachment of the prominence from the solar source region. From the location, timing, strength, and spectrum of HXR emission, we conclude that the prominence eruption is driven by the distinct events of magnetic reconnection occurring in the current sheet below the erupting prominence. These multi-wavelength observations also suggest that the localized magnetic reconnections associated with different evolutionary stages of the filament in the pre-eruption phase play an important role in destabilizing the active-region filament through the tether-cutting process, leading to large-scale eruption and X-class flare.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- July 2013
- DOI:
- 10.1088/0004-637X/771/1/1
- arXiv:
- arXiv:1305.1493
- Bibcode:
- 2013ApJ...771....1J
- Keywords:
-
- Sun: corona;
- Sun: flares;
- Sun: X-rays;
- gamma rays;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 16 pages, Accepted for publication in ApJ