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Duskside F-Region Dynamo Currents: Itsrelationship With Prereversal Enhancement Of Vertical Plasma Drift, P. Park, H. Luhr, Bela G. Fejer, K. W. Mim
Duskside F-Region Dynamo Currents: Itsrelationship With Prereversal Enhancement Of Vertical Plasma Drift, P. Park, H. Luhr, Bela G. Fejer, K. W. Mim
Bela G. Fejer
From magnetic field observations by CHAMP we estimate F-region dynamo current densities near the sunset terminator during solar maximum years from 2001 to 2002. The dynamo currents are compared with the pre-reversal enhancement (PRE) of vertical plasma drift as observed by ROCSAT-1. The seasonal-longitudinal variation of PRE can be largely related to the F-region dynamo current density, with the correlation coefficient reaching 0.74. The correlation can be further improved if we consider a zonal gradient of the E-region Pedersen conductivity, which also depends on season and longitude. It is widely accepted that the Fregion dynamo drives PRE near sunset. For …
Lunar Dependent Equatorial Ionospheric Effects During Sudden Stratosphericwarmings, Bela G. Fejer, M. E. Olson, J. L. Chau, C. Stolle, H. Luhr, L. P. Goncharenko, K. Yumoto, T. Nagatsuma
Lunar Dependent Equatorial Ionospheric Effects During Sudden Stratosphericwarmings, Bela G. Fejer, M. E. Olson, J. L. Chau, C. Stolle, H. Luhr, L. P. Goncharenko, K. Yumoto, T. Nagatsuma
Bela G. Fejer
[1] We have used plasma drift and magnetic field measurements during the 2001–2009 December solstices to study, for the first time, the longitudinal dependence of equatorial ionospheric electrodynamic perturbations during sudden stratospheric warmings. Jicamarca radar measurements during these events show large dayside downward drift (westward electric field) perturbations followed by large morning upward and afternoon downward drifts that systematically shift to later local times. Ground-based magnetometer measurements in the American, Indian, and Pacific equatorial regions show strongly enhanced electrojet currents in the morning sector and large reversed currents (i.e., counterelectrojets) in the afternoon sector with onsets near new and full …