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Kelvin‐Helmholtz instability and the variation of geomagnetic pulsation activity
Author(s) -
Lee L. C.,
Olson J. V.
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/gl007i010p00777
Subject(s) - magnetopause , magnetosheath , magnetosphere , physics , interplanetary magnetic field , geophysics , earth's magnetic field , solar wind , bow shock (aerodynamics) , amplitude , magnetic field , instability , atmospheric sciences , mechanics , shock wave , optics , quantum mechanics
It is shown that the observed local time variation of dayside geomagnetic micropulsations is consistent with the Kelvin‐Helmholtz generation mechanism operating at the magnetopause. The variation of the angle between the interplanetary magnetic field and the magnetopause around the magnetosphere causes variations in the magnetosheath magnetic field, which in turn lead to local time variations in micropulsation amplitudes. Morning sector pulsations are expected to be larger than afternoon sector pulsations. Furthermore, large‐amplitude pulsations are expected to be more frequently observed when the angle between the interplanetary magnetic field and the solar wind velocity in front of the bow shock is small.