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Current sheet flapping motion and structure observed by Cluster
Author(s) -
Sergeev V.,
Runov A.,
Baumjohann W.,
Nakamura R.,
Zhang T. L.,
Volwerk M.,
Balogh A.,
Rème H.,
Sauvaud J. A.,
André M.,
Klecker B.
Publication year - 2003
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 - 10.1029/2002gl016500
Subject(s) - flapping , plasma sheet , current sheet , tilt (camera) , physics , amplitude , plasma , current (fluid) , current density , magnetosphere , geometry , optics , wing , thermodynamics , magnetohydrodynamics , mathematics , quantum mechanics
Fast vertical flapping oscillations of the plasma sheet have been observed by Cluster on September 26, 2001. The flapping motion had vertical speeds exceeding 100 km/s, an amplitude in excess of 1 R E and a quasiperiod of ∼3 min. The current sheet was mostly tilted in the Y ‐ Z plane (with the tilt sometimes exceeding 45°). The waves had the properties of a kink mode and propagated toward the dusk flank. The flapping allowed to probe the vertical structure of the plasma sheet. Three different methods gave consistent evidence of a bifurcated structure of the cross‐tail current with about half of all current concentrated in two sheets (each ∼500–1000 km thick). The current density peaks at ∣ B x ∣ ∼ 0.5 B L , with a pronounced current density minimum and a plasma density plateau between these peaks.