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The neutral wind “flywheel” as a source of quiet‐time, polar‐cap currents
Author(s) -
Lyons L. R.,
Killeen T. L.,
Walterscheid R. L.
Publication year - 1985
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/gl012i002p00101
Subject(s) - interplanetary magnetic field , geophysics , convection , polar , solar wind , electric field , current (fluid) , atmospheric sciences , physics , polar cap , magnetic field , geology , ionosphere , meteorology , astronomy , quantum mechanics , thermodynamics
The neutral wind pattern over the summer polar cap can be driven by plasma convection to resemble the convection pattern. For a north‐south component of the interplanetary magnetic field B z directed southward, the wind speeds in the conducting E‐region can become ∼ 25% of the electric field drift speeds. If convection ceases, this neutral wind distribution can drive a significant polar cap current system for ∼ 6 hours. The currents are reversed from those driven by the electric fields for southward B z , and the Hall and field‐aligned components of the current system resemble those observed during periods of northward B z . The current magnitudes are similar to those observed during periods of small, northward B z ; however observations indicate that electric fields often contribute to the currents as much as, or more than, the neutral winds.