HR: 14:55h
AN: SM23C-05    [Abstracts]
TI: Dayside Magnetospheric Boundary Layer: Coordinated Observation by Cluster and Double Star
AU: * Zhang, H
EM: zhang@bu.edu
AF: Center for Space Physics, Boston University, 725 Commonwealth Ave, Boston, MA 02215
AU: Fritz, T
EM: fritz@bu.edu
AF: Center for Space Physics, Boston University, 725 Commonwealth Ave, Boston, MA 02215
AU: Zong, Q
EM: zong@bu.edu
AF: Center for Space Physics, Boston University, 725 Commonwealth Ave, Boston, MA 02215
AU: Daly, P
EM: daly@linmpi.mpg.de
AF: Max Planck Institute for Solar System Research, Max-Planck-Str. 2, Katlenburg-Lindau, 37191 Germany
AU: Balogh, A
EM: a.balogh@ic.ac.uk
AF: Space and Atmospheric Physics Group,Imperial College, Prince Consort Road, London, SW7 2BW United Kingdom
AB: The properties of the high latitude boundaries vary rather dramatically under different solar wind conditions. We present statistical results based on 4 years of data obtained by Cluster when these spacecraft were in the vicinity of the dayside magnetopause. During northward interplanetary magnetic field (IMF), the interfaces between the magnetosheath and magnetosphere are rather clear. The changes of the plasma density, temperature, velocity, energetic particle flux and magnetic field geometry across the magnetopause under northward IMF were analyzed by superposed epoch analysis. The plasma flow and density decrease and the proton temperature increases across the magnetopause from the magnetosheath into the cusp. Further, during extreme storm times, the cusp is more turbulent than during quiet times and there is no clear plasma density change across the magnetopause. During low density solar wind conditions, the magnitude of the parallel temperature change across the magnetopause is larger than during high density solar wind conditions. And the magnitude of the plasma density and velocity change is smaller than during high density solar wind conditions. On the other hand, the energetic ion spectra (30 keV - 4 MeV) are characterized by a power law and the power law index is found to be closely related to solar wind velocity. The spectra seem to be harder for higher solar wind velocity. The boundaries observed by Double Star in the same MLT but at different altitude than Cluster in 2004 and 2005 are also investigated.
DE: 7807 Charged particle motion and acceleration
DE: 7811 Discontinuities (2109)
DE: 7845 Particle acceleration
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005