HR: 1340h
AN: SM33A-1105 [Abstracts]
TI: Response of the magnetic field in the geosynchronous orbit to solar wind dynamic pressure pulses
AU: * Wang, C
EM: cw@spaceweather.ac.cn
AF: State Key Laboratory of Space Weather, Chinese Academy of Sciences, 1 NanErTiao,
ZhongGuanCun, Beijing, 100080, China
AU: Liu, J
EM: jbliu@spaceweather.ac.cn
AF: State Key Laboratory of Space Weather, Chinese Academy of Sciences, 1 NanErTiao,
ZhongGuanCun, Beijing, 100080, China
AU: Huang, Z
EM: zhhuang@spaceweather.ac.cn
AF: State Key Laboratory of Space Weather, Chinese Academy of Sciences, 1 NanErTiao,
ZhongGuanCun, Beijing, 100080, China
AU: Richardson, J D
EM: jdr@space.mit.edu
AF: Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77
Mass. Ave., Cambridge, MA 02139, United States
AB:
We do a statistical survey of solar wind dynamic pressure (Pd)
pulses and geosynchronous magnetic fields observed between 1998
and 2005. In geomagnetic quiet times with Dst>-50nT, we
find 111 solar wind dynamic pressure pulses which produce
geosynchronous magnetic field responses. These responses are
often observed by two or three GOES spacecraft at different local
times in geosynchronous orbit. The magnitudes of the
geosynchronous magnetic field changes (dBz) have a peak near
the noon meridian, similar to the results obtained in the study
of the response of the geosynchronous field to the large and
sharp solar wind dynamic pressure variations. However, the
relative change of the geosynchronous magnetic field
dBz/AV-Bz (where AV-Bz is the average of the
geosynchronous magnetic field Bz observed during the response
to the pressure pulse) depends weakly on the local time, thus the
change of Bz(dBz) is proportional to the average field
(AV-Bz). As the magnitude of the relative change of solar wind
dynamic pressure (dPd/Pd) increases, the rate of
geosynchronous magnetic field variation increases
correspondingly. These results imply that the magnitude of the
geosynchronous magnetic field response could be determined by
AV-Bz. In addition, the interplanetary field orientation does
not affect the response significantly. Using an MHD code which
models the global behavior of the solar
wind-magnetosphere-ionosphere system, we reproduce the main
characteristics of the observations.
DE: 2164 Solar wind plasma
DE: 2753 Numerical modeling
DE: 2784 Solar wind/magnetosphere interactions
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting