Ionosphere–Thermosphere Coupling in the Low-Latitude Region
The zonal neutral wind in the thermosphere flows strongly at the Earth’s magnetic dip equator instead of the geographic equator around 20 magnetic local time (MLT). On the other hand, the fast zonal plasma drift occurs in the low-latitude F region of evening ionosphere, but the velocity decreases at the magnetic dip equator. Therefore, the fast plasma drift velocity structure forms an arch in the frame of latitude and altitude in the evening. The fast zonal neutral wind occurs inside of the arch. Since the fast zonal plasma drift is strongly associated with equatorial ionization anomaly (EIA), we suggest that the ionosphere–thermosphere coupling associated with F-region dynamo is significantly important in the phenomenology of the low-latitude, F-region ionosphere and thermosphere. The fast neutral wind occurring in the evening F region over the magnetic dip equator may result in atmospheric super-rotation in the low-latitude thermosphere.
KeywordsNeutral Wind Magnetic Local Time Magnetic Latitude Plasma Drift Equatorial Ionization Anomaly
The author thanks H. Liu, H. Luhr, and M.A. Abdu for discussing data and its analyses. The author thanks the use of the DE-2 data in NSSDC of NASA.
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