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| Titel |
Analysis of plasmaspheric plumes: CLUSTER and IMAGE observations |
| VerfasserIn |
F. Darrouzet, J. Keyser, P. M. E. Décréau, D. L. Gallagher, V. Pierrard, J. F. Lemaire, B. R. Sandel, I. Dandouras, H. Matsui, M. Dunlop, J. Cabrera, A. Masson, P. Canu, J. G. Trotignon, J. L. Rauch, M. André |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 24, no. 6 ; Nr. 24, no. 6 (2006-07-03), S.1737-1758 |
| Datensatznummer |
250015584
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| Publikation (Nr.) |
 copernicus.org/angeo-24-1737-2006.pdf |
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| Zusammenfassung |
| Plasmaspheric plumes have been routinely observed by CLUSTER and IMAGE. The
CLUSTER mission provides high time resolution four-point measurements of the
plasmasphere near perigee. Total electron density profiles have been derived
from the electron plasma frequency identified by the WHISPER sounder
supplemented, in-between soundings, by relative variations of the spacecraft
potential measured by the electric field instrument EFW; ion velocity is
also measured onboard these satellites. The EUV imager onboard the IMAGE
spacecraft provides global images of the plasmasphere with a spatial
resolution of 0.1 RE every 10 min; such images acquired near apogee
from high above the pole show the geometry of plasmaspheric plumes, their
evolution and motion. We present coordinated observations of three plume
events and compare CLUSTER in-situ data with global images of the
plasmasphere obtained by IMAGE. In particular, we study the geometry and the
orientation of plasmaspheric plumes by using four-point analysis methods. We
compare several aspects of plume motion as determined by different methods:
(i) inner and outer plume boundary velocity calculated from time delays of
this boundary as observed by the wave experiment WHISPER on the four
spacecraft, (ii) drift velocity measured by the electron drift instrument
EDI onboard CLUSTER and (iii) global velocity determined from successive EUV
images. These different techniques consistently indicate that plasmaspheric
plumes rotate around the Earth, with their foot fully co-rotating, but with
their tip rotating slower and moving farther out. |
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