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On the cause of plasma‐sheet thinning during magnetospheric substorms
Author(s) -
Hill T. W.,
Reiff P. H.
Publication year - 1980
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/gl007i003p00177
Subject(s) - plasma sheet , current sheet , plasma , geophysics , physics , thinning , solar wind , heliospheric current sheet , magnetic field , computational physics , interplanetary magnetic field , magnetosphere , magnetohydrodynamics , nuclear physics , ecology , quantum mechanics , biology
We propose that the thinning of the plasma sheet during magnetospheric substorms is caused by an earthward gradient of the rate of magnetic merging (field annihilation) in the tail current sheet, which is in turn caused by the velocity‐dependent access of plasma mantle particles to the current sheet. A simple model calculation based on this effect predicts a thinning time constant of the order of 1 hour, consistent with observations. The mechanism is also consistent with the observed correlation between plasma‐sheet thinning and southward‐directed magnetic field components in the solar wind.