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An explanation for anomalous equatorial ionospheric electric fields associated with a northward turning of the interplanetary magnetic field
Author(s) -
Kelley M. C.,
Fejer B. G.,
Gonzales C. A.
Publication year - 1979
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/gl006i004p00301
Subject(s) - geophysics , interplanetary magnetic field , magnetosphere , electric field , ionosphere , interplanetary spaceflight , physics , ring current , ionospheric dynamo region , convection , perturbation (astronomy) , magnetic field , geology , solar wind , mechanics , astronomy , quantum mechanics
Anomalous reversals of the zonal equatorial electric field component have sometimes been observed when the interplanetary magnetic field turns northward from a steady southerly direction. We suggest that this reversal is associated with a sudden change in the convection electric field in the magnetosphere and present measurements to support this explanation. Although slower variations in the convection field are shielded from the low latitude ionosphere by polarization charges at the inner edge of the ring current, these charges may require an hour or more to vary. A sudden decrease in the cross‐tail electric field will thus be accompanied by a dusk‐dawn perturbation electric field across the inner magnetosphere.