The latitudinal distribution of ionospheric F2-layer Electron Density during geomagnetically quiet conditions has been investigated; using average hourly values of NmF2 for April, 2010, a year of low solar activity. Results obtained, reveals that the rate of ionization is higher at the equatorial and low latitudes, followed by the mid-latitude and lowest at the higher latitudinal region. The Equatorial Ionization anomaly (EIA) began to form at 1200 LT and was fully formed by 1300 LT. However; the southern EIA crest started forming 2 hours earlier than that of the Northern hemisphere. The peak NmF2 values for the Southern hemisphere (NmF2=1.49*10-3 e/cm3) occurred at 21.880 S geomagnetic latitude, while that of the Northern hemisphere (NmF2=1.45*10-3 e/cm3) was recorded at 18.720 N geomagnetic Latitude. This indicates that the EIA region for this period falls within 220 S to 190 N of the geomagnetic equator. Results of the diurnal variation of NmF2 observed at each station shows the occurrence of post sunset enhancement at all stations except TRS and ONW; the pre-noon peak was observed to be higher than the post-noon peak at some equatorial stations at low solar activity. This is different from the earlier findings reported in the literatures for the equatorial region and during low solar activity. These findings have been explained in terms of the intensity of the equatorial plasma fountain and thermospheric neutral wind processes.
Key words: Equatorial Ionosphere, F2-Layer, NmF2, Equatorial Ionization Anomaly, EIA
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