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Magnetic Activity Dependence of the Electric Drift Below L = 3
Author(s) -
Lejosne Solène,
Mozer F. S.
Publication year - 2018
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 - 10.1029/2018gl077873
Subject(s) - physics , dynamo , electric field , thermosphere , ionosphere , geophysics , amplitude , drift velocity , computational physics , local time , magnetic field , stochastic drift , dynamo theory , geomagnetic storm , earth's magnetic field , optics , quantum mechanics , statistics , mathematics
More than 2 years of magnetic and electric field measurements by the Van Allen Probes are analyzed with the objective of determining the average effects of magnetic activity on the electric drift below L = 3. The study finds that an increase in magnetospheric convection leads to a decrease in the magnitude of the azimuthal component of the electric drift, especially in the nightside. The amplitude of the slowdown is a function of L , magnetic local time, and Kp , in a pattern consistent with the storm time dynamics of the ionosphere and thermosphere. To a lesser extent, magnetic activity also alters the average radial component of the electric drift below L = 3. A global picture for the average variations of the electric drift with Kp is provided as a function of L and magnetic local time. It is the first time that the signature of the ionospheric disturbance dynamo is observed in near‐equatorial electric drift measurements.