Statistics of high-altitude and high-latitude O+ ion outflows observed by Cluster/CISS. Arvelius1, M. Yamauchi1, H. Nilsson1, R. Lundin1, Y. Hobara1, H. Rème2, M.B. Bavassano-Cattaneo3, G. Paschmann4, A. Korth5, L. M. Kistler6, and G. K. Parks71Swedish Institute of Space Physics (IRF), Box 812, 98128 Kiruna, Sweden
2Centre d’Etude Spatiale des Rayonnements, Toulouse, France
3Instituto di Fisica dello Spazio Interplanetario, Roma, Italy
4Max-Planck-Institut für Extraterrestrische Physik, Garching, Germany
5Max-Planck-Institut für Sonnensystemforschung, Katlenburg-Lindau, Germany
6University of New Hampshire, Durham, USA
7Space Science Laboratory, UC Berkeley, USA
Abstract. The persistent outflows of O+ ions observed by
the Cluster CIS/CODIF instrument were studied statistically
in the high-altitude (from 3 up to 11 RE)
and high-latitude (from 70 to ~90 deg invariant latitude,
ILAT) polar region. The principal results are: (1) Outflowing
O+ ions with more than 1keV are observed above 10 RE geocentric distance and above 85deg ILAT location;
(2) at 6-8 RE geocentric distance, the latitudinal
distribution of O+ ion outflow is consistent with velocity
filter dispersion from a source equatorward and below the
spacecraft (e.g. the cusp/cleft); (3) however, at 8-12 RE
geocentric distance the distribution of O+ outflows cannot
be explained by velocity filter only. The results suggest
that additional energization or acceleration processes for
outflowing O+ ions occur at high altitudes and high
latitudes in the dayside polar region.
Keywords. Magnetospheric physics (Magnetospheric configuration
and dynamics, Solar wind-magnetosphere interactions)
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Citation: Arvelius, S., Yamauchi, M., Nilsson, H., Lundin, R., Hobara, Y., Rème, H., Bavassano-Cattaneo, M.B., Paschmann, G., Korth, A., Kistler, L. M., and Parks, G. K.: Statistics of high-altitude and high-latitude O+ ion outflows observed by Cluster/CIS, Ann. Geophys., 23, 1909-1916, 2005. Bibtex EndNote Reference Manager