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Cluster observations of the exterior cusp and its surrounding boundaries under northward IMF
Author(s) -
Lavraud B.,
Dunlop M. W.,
Phan T. D.,
Rème H.,
Bosqued J.M.,
Dandouras I.,
Sauvaud J.A.,
Lundin R.,
Taylor M. G. G. T.,
Cargill P. J.,
Mazelle C.,
Escoubet C. P.,
Carlson C. W.,
McFadden J. P.,
Parks G. K.,
Moebius E.,
Kistler L. M.,
BavassanoCattaneo M.B.,
Korth A.,
Klecker B.,
Balogh A.
Publication year - 2002
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 - 10.1029/2002gl015464
Subject(s) - magnetosheath , cusp (singularity) , magnetopause , physics , geophysics , interplanetary magnetic field , diamagnetism , magnetic field , magnetic reconnection , magnetosphere , astrophysics , solar wind , geometry , mathematics , quantum mechanics
We have studied in detail multi‐spacecraft observations of the exterior cusp on 04 February 2001, during a steady northward Interplanetary Magnetic Field (IMF) interval. At a radial distance of 11 Re, Cluster encountered a well‐bounded region where the magnetic field exhibited very low diamagnetic values and the ions displayed high levels of isotropisation. We refer to this region as the Stagnant Exterior Cusp (SEC). Its equatorward edge is magnetopause like, whereas on the poleward side of the SEC, high‐speed plasma jets were observed consistent with a reconnection site poleward of the cusp. The SEC/magnetosheath boundary is characterized by abrupt changes in the magnetic field and plasma parameters that satisfy the Walén test, and by an S‐shaped magnetic hodogram. The latter may suggest the presence of an intermediate/slow transition.