HR: 08:30h
AN: SM51A-03    [PDF]
TI: Case Study of ULF Waves in the Cusp Region
AU: * Lin, N
EM: lin@waves.space.umn.edu
AF: University of Minnesota, School of Physics and Astronomy, Minneapolis, MN 55455 United States
AU: Zong, Q
EM: zong@bu.edu
AF: Boston University, Center for Space Physics, Boston, MA 02215 United States
AU: Fritz, T A
EM: fritz@bu.edu
AF: Boston University, Center for Space Physics, Boston, MA 02215 United States
AU: Tsurutani, B T
AF: Jet Propulsion Laboratory, MS 169-506, Pasadena, CA 91109 United States
AU: Korth, A
EM: korth@linmpi.mpg.de
AF: Max-Planck, Institut fur Aeronomie, Katlenburg-Lindau, D-37191 Germany
AU: Andr‚, M
EM: ma@irfu.se
AF: Swedish Institute of Space Physics, Box 537, Uppsala, 751 21 Sweden
AB: We investigate properties of ULF wave activity in the cusp region and the high latitude boundary layer (HLBL) during three polar cusp crossings of the Cluster spacecraft in March 2001. Various regions (the HLBL, plasma mantle, magnetosheath and the magnetopause) in a crossing event are identified by examining the signatures of energetic particles (30 - 1500 keV for ions and 20 - 400 keV for electrons) from the RAPID experiment and the variations of magnetic field and plasma parameters. Strong magnetic fluctuations are seen in the magnetosheath adjacent to the magnetopause and in the cusp. The Poynting flux of the waves in the magnetosheath is often seen flowing mainly in the direction of plasma bulk flow. In the cusp, strong wave energy flux is seen in some cases flowing toward the ionosphere, which may provide an important part of the the energy transported from the solar wind into the magnetosphere. We have also examined the signatures of possible wave mode conversion at the magnetopause, a phenomena often seen in the low latitude boundary layer, and compared the signatures with the field and plasma variations (e.g. the gradient of the Alfven velocity), which are predicted to be closely related to the phenomena. In HLBL, we observed the intensity of energetic ions pulsating at periods ranging from 100 to 300 sec. The relationship between these pulsations and the ULF waves will be discussed.
DE: 2724 Magnetopause, cusp, and boundary layers
DE: 2728 Magnetosheath
DE: 2731 Magnetosphere--outer
DE: 2752 MHD waves and instabilities
DE: 2784 Solar wind/magnetosphere interactions
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting