Open AccessPlasma sheet structure during strongly northward IMF
Author(s) -
Petrukovich A. A.,
Baumjohann W.,
Nakamura R.,
Balogh A.,
Mukai T.,
Glassmeier K.H.,
Reme H.,
Klecker B.
Publication year - 2003
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2002ja009738
Subject(s) - plasma sheet , current sheet , geophysics , magnetic reconnection , magnetic field , physics , geology , earth's magnetic field , flux (metallurgy) , shear (geology) , magnetosphere , magnetohydrodynamics , materials science , paleontology , quantum mechanics , metallurgy
On 14 September 2001, under stongly northward IMF conditions Cluster registered several fast magnetic field polarity changes which are usually attributed to thin (near‐equatorial) current sheet crossings. However, the IMF was northward for the previous 24 hours, the plasma sheet was expanded vertically, filled with cold, dense plasmas with high local vertical magnetic component B z , and the formation of a such cross‐tail thin current sheet was very unlikely. The analysis of multipoint measurements revealed that the detected sheets were almost vertically oriented, had strong shear and vanishing normal magnetic components, and therefore could be interpreted as boundaries between independent magnetic field domains (flux tubes) vertically indented relative to their neighbors, rather than crossings of the main cross‐tail current sheet. Such field reversals would be then observed by a spacecraft owing to horizontal flapping motion. Similar events were detected under analogous conditions by a pair of Geotail and Interball spacecraft, providing important evidence of significant spatial extent of areas with indented magnetic flux tubes along the tail. In conclusion we suggest how such anomalous structured magnetotail configuration might emerge in the course of high‐latitude reconnection of geomagnetic lobe and northward IMF.