HR: 0800h
AN: GP31A-0822    [Abstracts]
TI: Mapping the low-altitude cusp: intense small-scale field-aligned currents vs. energetic particle precipitation
AU: * Watermann, J
EM: jfw@dmi.dk
AF: Danish Meteorological Institute, Lyngbyvej 100, Copenhagen, 02100 Denmark
AU: Luehr, H
EM: hluehr@gfz-potsdam.de
AF: GeoForschungszentrum Potsdam, Telegraphenberg, Potsdam, 14473 Germany
AU: Newell, P T
EM: patrick.newell@jhuapl.edu
AF: Johns Hopkins University, Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723-6099 United States
AU: Stauning, P
EM: pst@dmi.dk
AF: Danish Meteorological Institute, Lyngbyvej 100, Copenhagen, 02100 Denmark
AU: Christiansen, F
EM: fch@dsri.dk
AF: Danish Space Research Institute, Juliane Maries Vej 30, Copenhagen, 02100 Denmark
AU: Schlegel, K
EM: schlegel@linmpi.mpg.de
AF: Max-Planck-Institute for Solar System Research, Max-Planck-Strasse 2, Katlenburg-Lindau, 37191 Germany
AB: We have studied more than 50 cases of cusp observations from low-altitude satellites during the February 16-22, 2002, SIRCUS campaign period. About half of them were inferred from DMSP F-13/14/15 particle spectrometer data and the other half from magnetic field measurements in the lower ELF range made onboard the CHAMP and {\O}rsted LEO satellites. The locations of the satellites during the detection of these signatures were converted into AACGM coordinates, and the geomagnetic latitude of these signatures set in relation to the statistical, IMF-Bz dependent particle cusp latitude derived by Newell et al. (1989). The particle cusp latitude which we inferred from DMSP data matches the statistically expected latitude while the small-scale magnetic field regime appears to cover the equatorward section of the cusp and the poleward section of the low-latitude boundary layer (LLBL). We suggest that the perturbations resulting in small-scale magnetic field variations are generated in the LLBL-cusp transition zone, possibly associated with turbulence or instabilities generated in the process of opening geomagnetic field lines and merging them with the interplanetary field.
DE: 2409 Current systems (2708)
DE: 2455 Particle precipitation
DE: 2475 Polar cap ionosphere
DE: 2481 Topside ionosphere
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2004 AGU Fall Meeting