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The interplanetary and magnetospheric causes of extreme d B /d t at equatorial locations
Author(s) -
Adebesin Babatunde O.,
Pulkkinen Antti,
Ngwira Chigomezyo M.
Publication year - 2016
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 - 10.1002/2016gl071526
Subject(s) - solar wind , space weather , ionosphere , earth's magnetic field , interplanetary spaceflight , physics , electrojet , equatorial electrojet , interplanetary magnetic field , atmospheric sciences , geomagnetic storm , geophysics , magnetic field , quantum mechanics
The 1 min resolution solar wind and geomagnetic data obtained from seven equatorial/low‐latitude stations during four extreme geomagnetic activities are used to investigate the extreme d B/ d t perturbations. Simulations of the magnetospheric‐ionospheric environment were also performed for varying amplitudes of the solar proton density. Simulations were carried out using the Space Weather Modeling Framework/BATS‐R‐US + RCM model. Both the observations and simulations demonstrated that the appearance time of the extreme d B/ d t perturbations at equatorial stations during disturbed conditions is instantaneous and equitable to those experienced at auroral regions yielding time lags of the order of a few seconds. We find that the rapid d B/ d t enhancements are caused by the electric field of magnetospheric current origin, which is being enhanced by solar wind density and ram pressure variations and boosted by the equatorial electrojet. Our results indicate that the solar wind proton density variations could be used as a predictor of extreme d B/ d t enhancement at equatorial latitudes.