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Equatorial Disturbance Dynamo Vertical Plasma Drifts Over Jicamarca: Bimonthly and Solar Cycle Dependence
Author(s) -
Navarro L. A.,
Fejer B. G.,
Scherliess L.
Publication year - 2019
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1029/2019ja026729
Subject(s) - solstice , equinox , noon , atmospheric sciences , dynamo , ionosphere , environmental science , daytime , local time , earth's magnetic field , dusk , disturbance (geology) , solar cycle , solar minimum , climatology , physics , geology , geodesy , solar wind , latitude , geophysics , plasma , astronomy , paleontology , statistics , mathematics , quantum mechanics , magnetic field
We use extensive incoherent scatter radar observations from the Jicamarca Radio Observatory to study the local time and bimonthly dependence of the equatorial disturbance dynamo vertical plasma drifts on solar flux and geomagnetic activity. We show that the daytime disturbance drifts have generally small magnitudes with largest values before noon and an apparent annual variation. Near dusk, they are downward throughout the year with largest values during the equinoxes and smallest during June solstice. These downward drifts increase strongly with solar flux and shift to later local times. They also increase with increasing geomagnetically active conditions with no apparent local time shift. The equinoctial evening downward disturbance drifts are larger during the autumnal equinox than during the vernal equinox. The nighttime disturbance drifts are upward and have small seasonal and solar cycle dependence but increase strongly with geomagnetic activity, particularly in the late night sector. Our results are in general agreement with those from previous theoretical and experimental studies, except near dusk where our results show much stronger seasonal and solar cycle dependence.