HR: 1340h
AN: SH13A-0288    [Abstracts]
TI: A Statistical Analysis of Loop-Top Motion in Solar Limb Flares
AU: * Holman, G D
EM: Gordon.D.Holman@nasa.gov
AF: NASA's Goddard Space Flight Center, Code 612.1, Greenbelt, MD 20771 United States
AU: Sui, L
EM: Linhui.Sui@gsfc.nasa.gov
AF: NASA's Goddard Space Flight Center, Code 612.1, Greenbelt, MD 20771 United States
AU: Sui, L
EM: Linhui.Sui@gsfc.nasa.gov
AF: The Catholic University of America, 620 Michigan Avenue, N. E., Washington, DC 20064 United States
AU: Brosius, D G
EM: 25brosius@cua.edu
AF: The Catholic University of America, 620 Michigan Avenue, N. E., Washington, DC 20064 United States
AU: Dennis, B R
EM: Brian.R.Dennis@nasa.gov
AF: NASA's Goddard Space Flight Center, Code 612.1, Greenbelt, MD 20771 United States
AB: Previous studies of hot, thermal solar flare loops imaged with the Ramaty High Energy Solar Spectroscopic Imager (RHESSI) have identified several flares for which the loop top shrinks downward early in the impulsive phase and then expands upward later in the impulsive phase (Sui & Holman 2003; Sui, Holman & Dennis 2004; Veronig et al. 2005). This early downward motion is not predicted by flare models. We study a statistical sample of RHESSI flares to assess how common this evolution is and to better characterize it. In a sample of 88 flares near the solar limb that show identifiable loop structure in RHESSI images, 66% (58 flares) showed downward loop-top motion followed by upward motion. We therefore conclude that the early downward motion is a frequent characteristic of flare loops. We obtain the distribution of the timing of the change from downward to upward motion relative to flare start and peak times. We also obtain the distributions of downward and upward speeds. This work was supported in part by NASA SEC Guest Investigator Grant 370-16-20-16 and by the RHESSI project.
DE: 7519 Flares
DE: 7526 Magnetic reconnection (2723, 7835)
DE: 7554 X-rays, gamma rays, and neutrinos
SC: SPA-Solar and Heliospheric Physics [SH]
MN: Fall Meeting 2005