HR: 11:30h
AN: SM22A-05    [Abstracts]
TI: Multiple Satellite Measurements of Particles and Fields During High Solar Wind Pressure Period
AU: * Chen, J
EM: jschen@bu.edu
AF: Center for Space Physics, Boston University, 725 Commonwealth Avenue, Boston, MA 02215 United States
AU: Fritz, T A
EM: fritz@bu.edu
AF: Center for Space Physics, Boston University, 725 Commonwealth Avenue, Boston, MA 02215 United States
AU: Sheldon, R B
EM: Rob.Sheldon@msfc.nasa.gov
AF: NASA/MSFC/NSSTC/SD50, 320 Sparkman, Huntsville, AL 35805 United States
AB: The WIND spacecraft (near L1) observed a high solar wind pressure period from 4:45 UT to 6:00 UT and an upstream ion event at 5:23-5:45 UT on June 28, 1999. The POLAR satellite at 7 hours magnetic local time ovserved a cusp-like diamagnetic cavity from 5:12 UT to 6:27 UT. Most of the time, during the period, the interplanetary magnetic field (IMF) had a duskward component, suggesting that cusp diamagnetic cavities also existed in the post-noon in the Northern Hemisphere. The diamagnetic cavity observaed by POLAR is independent of the solar wind velocity. The enhancements of the magnetic field fluctuations in the ultra-low frequency range measured by the WIND were also detected by the POLAR. The He⁺⁺/H⁺ ratio in the diamagnetic cavities was a factor of four higher than in the quasi-trapping region before the event onset, while the He⁺/He⁺⁺ ratio in the cavities was more than one order of the magnitude lower. The INTERBALL-1 spacecraft located just upstream of the bow shock on the pre-noon measured an upstream ion event from about 5:16 UT to 6:00 UT. The onset of the energetic ions observed by INTERBALL-1 in the upstream event was the same for different energies; the ion energy spectra were independent of the solar wind velocity and their intensities were independent of the bow shock geometry and the solar wind density. The energetic ion event onset was first detected near the cusp by POLAR at 5:12 UT, then near the bow shock in the pre-noon by INTERBALL-1 at 5:16 UT, and then in the far upstream by WIND at 5:23 UT. The measured energetic ion intensity decreased with increasing distance from the cusp diamagnetic cavities. These observational facts together with the IMF directions suggest that (1) this high solar wind pressure event produced an extremely large diamagnetic cavities (> 10 R_E) within the magnetosphere, (2) the bow shock was not the main source of both the cusp and upstream energetic ions, and (3) the upstream energetic ions most likely came from the cusp.
DE: 2134 Interplanetary magnetic fields
DE: 2164 Solar wind plasma
DE: 2724 Magnetopause, cusp, and boundary layers
DE: 2740 Magnetospheric configuration and dynamics
DE: 2784 Solar wind/magnetosphere interactions
SC: SPA-Magnetospheric Physics [SM]
MN: 2005 Joint Assembly