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What drives magnetospheric activity under northward IMF conditions?
Author(s) -
Pulkkinen T. I.,
Palmroth M.,
McPherron R. L.
Publication year - 2007
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 - 10.1029/2007gl030619
Subject(s) - solar wind , magnetosphere , geophysics , electric field , interplanetary magnetic field , magnetohydrodynamics , physics , atmospheric sciences , magnetic field , quantum mechanics
We show that the dependence of magnetospheric activity on the driving solar wind electric field is qualitatively different for northward and southward IMF conditions. For southward IMF, the AE‐index is driven by the solar wind electric field, but for a given E Y , AE is higher when the solar wind speed is higher. For northward IMF, AE does not scale with the electric field, but is lowest for low solar wind speed and small IMF clock‐angles. These results are explained by a quantitative analysis of the amount of energy that enters the magnetosphere using the GUMICS‐4 global MHD simulation.