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Spatial gradients in the plasmasphere from Cluster
Author(s) -
Darrouzet F.,
De Keyser J.,
Décréau P. M. E.,
Lemaire J. F.,
Dunlop M. W.
Publication year - 2006
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2006gl025727
Subject(s) - plasmasphere , density gradient , azimuth , physics , transverse plane , electron density , cluster (spacecraft) , computational physics , field line , magnetic field , geophysics , geology , electron , magnetosphere , astronomy , structural engineering , engineering , quantum mechanics , computer science , programming language
The Cluster mission allows the study of the plasmasphere with four‐point measurements, including its overall density distribution, plasmaspheric plumes close to the plasmapause, and density irregularities inside the plasmasphere. The purpose of this letter is to examine the geometry and orientation of the overall density structure and of the magnetic field. We present a typical Cluster plasmasphere crossing for which we compute the four‐point spatial gradient of the electron density and the magnetic field strength, and we compare the direction of both gradients with the local field vector. We discuss the role of the gradient components along and transverse to field lines; transverse density gradients, in particular, are found to suggest the presence of azimuthal density variations.