HR: 0800h
AN: AE31A-0042    [Abstracts]
TI: Sprites and lightning in Venus: constraints for observations by the Planet-C mission
AU: * Takahashi, Y
EM: yukihiro@pat.geophys.tohoku.ac.jp
AF: Tohoku University, 6-3 Aza-aoba, Aramaki, Aoba-ku, Sendai, 980-8578, Japan
AU: Yair, Y
EM: yoavya@openu.ac.il
AF: The Open University of Israel, P.O. Box 808, Ra'anana, 43107, Israel
AU: Goto, Y
EM: yukigoto@tjcc.tohoku-gakuin.ac.jp
AF: Tohoku Gakuin University, 1-13-1, Chuo, Tagajo, 985-8537, Japan
AU: Sentman, D
AF: University of Alaska, Fairbanks, 108 Natural Sciences Facility 708E Elvey Building, P.O. Box 757500, Fairbanks, AK 99775, United States
AU: Yoshida, J
AF: Tohoku University, 6-3 Aza-aoba, Aramaki, Aoba-ku, Sendai, 980-8578, Japan
AU: Sato, M
AF: Tohoku University, 6-3 Aza-aoba, Aramaki, Aoba-ku, Sendai, 980-8578, Japan
AU: Hoshino, N
AF: Tohoku University, 6-3 Aza-aoba, Aramaki, Aoba-ku, Sendai, 980-8578, Japan
AB: Lightning activity in Venus has been mystery for long period, although many studies based on observations both by spacecrafts and by ground-based telescope have been carried out. This situation may be attributed to the ambiguity of these evidential measurements. In order to conclude this controversial subject, we are developing a new type of lightning detector, LAC (Lightning and Airglow Camera), which will be onboard Planet-C (Venus Climate Orbiter: VCO). PLanet-C will be launched in 2010 by JAXA. To distinguish optical lightning flash from other pulsing noises, high-speed sampling at 50kHz for each pixel, that enables us to investigate the time variation of each lightning flash phenomenon, is adopted. On the other hand, spatial resolution is not first priority. For this purpose we developed new type of APD (avalanche photo diode) array with a format of 8 x 8. Narrow band interference filter at wavelength of 777.4 nm (OI), which is expected lightning color based on laboratory discharge experiment, is chosen for lightning measurement. LAC detects lightning flash with an optical intensity of average of Earthfs lightning or less at a distance of 3 Rv. We also present results of theoretical calculations of the expected occurrance heights and emissions of sprites above thunderstorms in the CO2 atmosphere of Venus and the Hydrogen-Helium atmospheres of Jupiter and Saturn. General detection methodology of sprites/lightning in planetary atmospheres by orbiting spacecraft will be discussed.
DE: 0343 Planetary atmospheres (5210, 5405, 5704)
DE: 3324 Lightning
DE: 6295 Venus
SC: Atmospheric and Space Electricity [AE]
MN: 2007 Fall Meeting