HR: 1330h
AN: SM52B-0594    [PDF]
TI: Response of the Geosynchronous Magnetic Field at the Sub-solar Region to Variations in Interplanetary Magnetic Field Orientations and Changes in Solar Wind Dynamic Pressure
AU: * Chao, J K
EM: jkchao@jupiter.ss.ncu.edu.tw
AF: Institute of Space Science, National Central University, No.300, Jung-Da Road, Chung-li, 32001 Taiwan
AU: Dmitriev, A V
EM: dalex@jupiter.ss.ncu.edu.tw
AF: Institute of Space Science, National Central University, No.300, Jung-Da Road, Chung-li, 32001 Taiwan
AU: Yang, Y H
EM: allen@jupiter.ss.ncu.edu.tw
AF: Institute of Space Science, National Central University, No.300, Jung-Da Road, Chung-li, 32001 Taiwan
AB: The magnetic fields Ht at the geosynchronous orbit near the dayside sub-solar region are compared with the up-stream solar wind dynamic pressure (Dp) and north-south component of interplanetary field (Bz) in GSM coordinates based on the 90-second resolution of data observed by WIND, ACE, GOES 8 and 10 satellites for the period 1999-2000. The corrections due to the changes of the latitudinal positions of GOES have been made. There are at most two events selected (one for each GOES) each day when GOES 8 and 10 reach their maximum values of magnetic field strength near the sub-solar region. A total of 507 events are selected such that the up-stream solar wind and IMF data are carefully compared with GOES data so that a proper adjustment for the time delay due to solar-wind propagation from the upstream positions to that of GOES is included. It is found that the well-known results of Ht = a*sqrt(Dp)+b are confirmed for both polarity of Bz where a=30.2, b= 80.2, Ht in nT and Dp in nPa. However, the reduction in Ht due to the negative Bz is not found in our statistical study. Using the magnetopause model of Chao et al. (2002) and Shue et al. (1998), we estimate that the sub-solar distance of the magnetopause, Rmp, reduces about 1 Re on the average for southward Bz when Rmp is in the range of 7 to 10 Re.
DE: 2740 Magnetospheric configuration and dynamics
DE: 2784 Solar wind/magnetosphere interactions
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting