Modeling the new structures discovered in the plasmasphere

V. Pierrard


New structures like plumes, notches, shoulders and channels were recently discovered
in the plasmasphere with the observations of the satellite IMAGE. Indeed, this spacecraft
provided the first global comprehensive images of the EarthÕs plasmasphere by
the EUV (Extreme UltraViolet) instrument, revealing the large-scale dynamics of the
plasmasphere and its interactions with other particle populations. The four satellites
of CLUSTER have also revealed new density structures and observations of plumes.
These new observations give an exceptional opportunity to check the mechanisms
proposed for formation of the plasmapause and of the plumes. Some tentative explanations
and possible mechanisms proposed for the formation of the structures will be
presented. In particular, I will compare the satellite observations of the plasmasphere
and the results of the dynamical simulations that have been developed at the Belgian
Institute for Space Aeronomy to simulate the deformation of the plasmasphere during
geomagnetic substorms and other variations in the level of geomagnetic activity.

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European Geosciences Union General Assembly, Vienna, Austria, 2-7 April 2006