HR: 0800h
AN: AE31A-0051    [Abstracts]
TI: Unusual RHESSI TGFs: Electron Beams and Others
AU: * Smith, D M
EM: dsmith@scipp.ucsc.edu
AF: Physics Department and Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, 1156 High St., Santa Cruz, CA 95064, United States
AU: Dwyer, J R
EM: jdwyer@fit.edu
AF: Department of Physics and Space Sciences, Florida Institute of Technology, 150 West University Blvd., Melbourne, FL 32901, United States
AU: Grefenstette, B W
EM: bwgref@scipp.ucsc.edu
AF: Physics Department and Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, 1156 High St., Santa Cruz, CA 95064, United States
AU: Hazelton, B J
EM: bhazelto@physics.ucsc.edu
AF: Physics Department and Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, 1156 High St., Santa Cruz, CA 95064, United States
AU: Yair, Y
EM: yoavya@openu.ac.il
AF: Department of Natural Sciences, Open University of Israel, 108 Ravutski Street, Ra'anana, 43107, Israel
AU: Bor, J
EM: jbor@ggki.hu
AF: Hungarian Academy of Sciences, Geodetic and Geophysical Institute, Csatkai Endre u. 6-8, Sopron, H-9400, Hungary
AU: Lay, E H
EM: erinlay@u.washington.edu
AF: Department of Earth and Space Sciences, University of Washington, Box 351310, Seattle, WA 98195, United States
AU: Holzworth, R H
EM: bobholz@ess.washington.edu
AF: Department of Earth and Space Sciences, University of Washington, Box 351310, Seattle, WA 98195, United States
AB: We will summarize observations and conclusions about two unusual Terrestrial Gamma-ray Flashes (TGFs) observed by the RHESSI satellite. Both events are unusually bright and occur in the Northern hemisphere during the winter -- unusual in itself, since TGFs are overall a phenomenon associated with summer storms. The first event, on January 17, 2004, can be modeled as the signature of the satellite passing through an electron beam ejected from the atmosphere at the magnetic conjugate point. The mechanism behind this process is now understood, and will be presented here and, in more depth, in the accompanying paper by Dwyer, Grefenstette, and Smith in this session. The second event occurred in the Mediterranean -- the only TGF ever reported in that region -- on November 7, 2004. This event seems to be associated with a nearby thunderstorm, not a conjugate one, but is still extremely unusual. We will examine the question of whether its unusual location and brightness is due to its being another electron beam event (caught on the way out instead of the way back in), or whether the storm itself was unique. Finally, we will briefly show the other RHESSI TGFs with the most extreme behavior in duration, average energy per photon, and geographical location.
DE: 2716 Energetic particles: precipitating
DE: 2736 Magnetosphere/ionosphere interactions (2431)
DE: 3304 Atmospheric electricity
DE: 3324 Lightning
SC: Atmospheric and Space Electricity [AE]
MN: 2007 Fall Meeting