HR: 15:45h
AN: SP44A-02    [Abstracts]
TI: Flare Emission Onset in the Slow-Rise and Fast-Rise Phases of an Erupting Solar Filament Observed with TRACE
AU: * Sterling, A C
EM: alphonse.sterling@nasa.gov
AF: NASA/MSFC, NSSTC/XD12 320 Sparkman Dr., Huntsville, AL 35805 United States
AU: Moore, R L
EM: ron.moore@nasa.gov
AF: NASA/MSFC, NSSTC/XD12 320 Sparkman Dr., Huntsville, AL 35805 United States
AB: We observe the eruption of an active-region solar filament of 1998 July~11 using high time cadence and high spatial resolution EUV observations from the TRACE satellite, along with soft X-ray images from the soft X-ray telescope (SXT) on the Yohkoh satellite, hard X-ray fluxes from the BATSE instrument on the ( CGRO) satellite and from the hard X-ray telescope (HXT) on Yohkoh, and ground-based magnetograms. We concentrate on the initiation of the eruption in an effort to understand the eruption mechanism. First the filament undergoes slow upward movement in a "slow rise" phase with an approximately constant velocity of ≈ 15~km~s^-1 that lasts about 10~min, and then it erupts in a "fast-rise" phase, reaching a velocity of ≈ 200~km~s^-1 in about 5~min, followed by a period of deceleration. EUV brightenings begin just before the start of the filament's slow rise, and remain immediately beneath the rising filament during the slow rise; initial soft X-ray brightenings occur at about the same time and location. Strong hard X-ray emission begins after the onset of the fast rise, and does not peak until the filament has traveled a substantial altitude (to a height about equal to the initial length of the erupting filament) beyond its initial location. Our observations are consistent with the slow-rise phase of the eruption resulting from the onset of "tether cutting" reconnection between magnetic fields beneath the filament, and the fast rise resulting from an explosive increase in the reconnection rate or by catastrophic destabilization of the overlying filament-carrying fields. About two days prior to the event new flux emerged near the location of the initial brightenings, and this recently-emerged flux could have been a catalyst for initiating the tether-cutting reconnection. With the exception of the initial slow rise, our findings qualitatively agree with the prediction for erupting-flux-rope height as a function of time in a model discussed by Chen & Shibata~(2000) based on reconnection between emerging flux and a flux rope. NASA supported this work through NASA SR&T and SEC GI grants.
DE: 7513 Coronal mass ejections
DE: 7519 Flares
DE: 7524 Magnetic fields
DE: 7531 Prominence eruptions
SC: Solar Physics Division - AAS [SP]
MN: 2005 Joint Assembly