HR: 1330h
AN: SM12A-1195    [PDF]
TI: A FIELD LINE TOPOLOGY TRACER -- CLUSTER ENERGETIC ELECTRONS OBSERVATIONS IN THE HIGH LATITUDE BOUNDARY / CUSP REGIONs
AU: * Zong, Q
EM: zong@bu.edu
AF: Center For Space Physics, Boston University,, Commonwealth Ave. 725, Boston, MA 02215 United States
AU: Fritz, T
EM: fritz@bu.edu
AF: Center For Space Physics, Boston University,, Commonwealth Ave. 725, Boston, MA 02215 United States
AU: Korth, A
EM: korth@linmpi.mpg.de
AF: Max-Planck-Institut fur Aeronomie,, Max-Planck-Str. 2, 37191, Katlenburg-Lindau, NS 37191 Germany
AU: Daly, P
EM: daly@linmpi.mpg.de
AF: Max-Planck-Institut fur Aeronomie,, Max-Planck-Str. 2, 37191, Katlenburg-Lindau, NS 37191 Germany
AU: Dunlop, M
EM: m.dunlop@ic.ac.uk
AF: Space and Atmospheric Physics Group, The Blackett Laboratory,, Imperial College, Prince Consort Road, London, London, LD SW7 2BZ United Kingdom
AU: Balogh, A
EM: balogh@ic.ac.uk
AF: Space and Atmospheric Physics Group, The Blackett Laboratory,, Imperial College, Prince Consort Road, London, London, LD SW7 2BZ United Kingdom
AU: Reme, H
EM: Henri.Reme@cesr.fr
AF: CESR,, BP 4346, 31028, Toulouse, TL 31028 France
AU: Dandouras, J
EM: Dandouras@cesr.fr
AF: CESR,, BP 4346, 31028, Toulouse, TL 31028 France
AB: Energetic electrons (e.g. 50 keV) travel along field lines with a high speed of around 20 $R_Es^{-1}$. These swift electrons trace out field lines in the magnetosphere in a rather short time, therefore, can provide nearly instantaneous information about the changes in the field configuration in the geospace regions. The energetic electrons in the high latitude boundary regions (including the cusp) have been examined in detail by using Cluster/RAPID data for four consecutive high latitude/ cusp crossings between 16 March to 19 March 2001. Energetic electrons with high and stable fluxes were observed in the time interval when the IMF had a predominately positive Bz component. These electrons appeared to be associated with a lower plasma density exhibiting no obvious tailward plasma flow ($<$ 20 keV). On the other hand, no electrons or only spike -like electron events have been observed in the cusp region during southward IMF. At this time, the plasma density was as high as that in the magnetosheath and it was associated with a clear tailward flow. The fact that no stable energetic electron fluxes were observed during southward IMF indicates that the cusp has an open field line geometry. The observations indicate that both the south and north high latitude magnetospheric boundary regions (including both north and south cusp) can be energetic particle trapping regions. The energetic electron observations provide new evidences to understand the dynamic cusp processes. Finally, the trajectory tracing of test particles have been performed by using the Tsyganenko 96 model which demonstrates that energetic particles (both ions and electrons) could be indeed trapped in the high latitude magnetosphere.
DE: 2407 Auroral ionosphere (2704)
DE: 2409 Current systems (2708)
DE: 2411 Electric fields (2712)
DE: 2475 Polar cap ionosphere
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting