Model-observation comparison for the geographic variability of the plasma electric drift in the Earth's innermost magnetosphere

TitleModel-observation comparison for the geographic variability of the plasma electric drift in the Earth's innermost magnetosphere
Publication TypeJournal Article
Year of Publication2017
AuthorsLejosne, ène, Maus, S, Mozer, FS
JournalGeophysical Research Letters
Date Published07/2017
Keywordscorotation; electric field; Ionosphere; plasmasphere; thermosphere; Van Allen Probes; wind
AbstractPlasmaspheric rotation is known to lag behind Earth rotation. The causes for this corotation lag are not yet fully understood. We have used more than two years of Van Allen Probe observations to compare the electric drift measured below L~2 with the predictions of a general model. In the first step, a rigid corotation of the ionosphere with the solid Earth was assumed in the model. The results of the model-observation comparison are twofold: (1) radially, the model explains the average observed geographic variability of the electric drift; (2) azimuthally, the model fails to explain the full amplitude of the observed corotation lag. In the second step, ionospheric corotation was modulated in the model by thermospheric winds, as given by the latest version of the Horizontal Wind Model (HWM14). Accounting for the thermospheric corotation lag at ionospheric E-region altitudes results in significantly better agreement between the model and the observations.
URLonlinelibrary.wiley.com/doi/10.1002/2017GL074862/full
DOI10.1002/2017GL074862
Short TitleGeophys. Res. Lett.


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