HR: 0800h
AN: SM11A-1178    [Abstracts]
TI: Spatial Structure of Alfven and Sound Speeds in the Magnetotail
AU: * Lee, K
EM: kieslow@khu.ac.kr
AF: Department of Astronomy and Space Science, Kyung Hee University, Yongin, Kyunggi, 449701 Korea, Republic of
AU: Kim, K
EM: khan@khu.ac.kr
AF: Department of Astronomy and Space Science, Kyung Hee University, Yongin, Kyunggi, 449701 Korea, Republic of
AU: Lee, D
EM: dhlee@khu.ac.kr
AF: Department of Astronomy and Space Science, Kyung Hee University, Yongin, Kyunggi, 449701 Korea, Republic of
AB: Magnetohydrodynamic (MHD) waves are believed to be a global indicator of magnetotail processes. Even if the wave source is localized, the wave propagates to various parts of the magnetosphere and thus dynamical phenomena in the magnetotail would be monitored. Since the plasma density and magnetic field are spatially variable, the phase fronts of the MHD waves are highly distorted due to inhomogeneity. Thus, it is important to understand the global spatial structure of MHD wave speed. To calculate the wave speed in the magnetotail, we use the plasma and magnetic field data acquired from the Geotail spacecraft in two years (1996-1997). From these statistical values, we present the map of Alfven and sound speeds in the near-Earth magnetotail ($\vert \rm X_{GSM} \vert = 10 \sim 30 R_E$, $\vert \rm Y_{GSM} \vert < 10 R_E$). We also investigate the effects of seasonal variations and geomagnetic activities on these speed profiles.
DE: 2700 MAGNETOSPHERIC PHYSICS
DE: 2744 Magnetotail
DE: 2748 Magnetotail boundary layers
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting