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Analysis of plasmaspheric plumes: CLUSTER and IMAGE observations and numerical simulationsPlasmaspheric 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 can be derived from the plasma frequency and/or from the spacecraft potential (note that the electron spectrometer is usually not operating inside the plasmasphere); ion velocity is also measured onboard these satellites (but ion density is not reliable because of instrumental limitations). The EUV imager onboard the IMAGE spacecraft provides global images of the plasmasphere with a spatial resolution of 0.1 RE every 10 minutes; such images acquired near apogee from high above the pole show the geometry of plasmaspheric plumes, their evolution and motion. We present coordinated observations for 3 plume events and compare CLUSTER in-situ data (panel A) with global images of the plasmasphere obtained from IMAGE (panel B), and with numerical simulations for the formation of plumes based on a model that includes the interchange instability mechanism (panel C). In particular, we study the geometry and the orientation of plasmaspheric plumes by using a four-point analysis method, the spatial gradient. We also compare several aspects of their motion as determined by different methods: (i) inner and outer plume boundary velocity calculated from time delays of this boundary observed by the wave experiment WHISPER on the four spacecraft, (ii) ion velocity derived from the ion spectrometer CIS onboard CLUSTER, (iii) drift velocity measured by the electron drift instrument ED1 onboard CLUSTER and (iv) 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.
Document ID
20050215631
Acquisition Source
Marshall Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Darouzet, Fabien
(Belgian Inst. for Space Astronomy Brussels, Belgium)
DeKeyser, Johan
(Belgian Inst. for Space Astronomy Brussels, Belgium)
Decreau, Pierrette
(Centre National de la Recherche Scientifique Orleans, France)
Gallagher, Dennis
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Pierrard, Viviane
(Belgian Inst. for Space Astronomy Brussels, Belgium)
Lemaire, Joseph
(Belgian Inst. for Space Astronomy Brussels, Belgium)
Dandouras, Iannis
(Centre d'Etude Spatiale des Rayonnements Toulouse, France)
Matsui, Hiroshi
(New Hampshire Univ. Durham, NH, United States)
Dunlop, Malcolm
(Rutherford Appleton Lab. Chilton, United Kingdom)
Andre, Mats
(Swedish Inst. of Space Physics Uppsala, Sweden)
Date Acquired
August 23, 2013
Publication Date
January 1, 2005
Subject Category
Geosciences (General)
Meeting Information
Meeting: Session C5 of the General Congress of the French Physical Society and Belgian Physical Society
Location: Lille
Country: France
Start Date: August 29, 2005
End Date: September 2, 2005
Distribution Limits
Public
Copyright
Other

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