Effect of vertical plasma transport on ionospheric F2-region parameters at equatorial latitude

Abstract

The variability of the F2-layer even during magnetically quiet times are fairly complex owing to the effects of plasma transport. The vertical E × B drift velocities (estimated from simplified electron density continuity equation) were used to investigate the seasonal effects of the vertical ion drifts on the bottomside daytime ionospheric parameters over an equatorial latitude in West Africa, Ibadan, Nigeria (Geographic: 7.4°N, 3.9°E, dip angle: 6°S) using 1 year of ionsonde data during International Geophysical Year (IGY) of 1958, that correspond to a period of high solar activity for quiet conditions. The variation patterns between the changes of the vertical ion drifts and the ionospheric F2-layer parameters, especially; f oF 2 and h mF 2 are seen remarkable. On the other hand, we observed strong anti-correlation between vertical drift velocities and h′F in all the seasons. We found no clear trend between N mF 2 and h mF 2 variations. The yearly average value of upward daytime drift at 300 km altitude was a little less than the generally reported magnitude of 20 ms −1 for equatorial F-region in published literature, and the largest upward velocity was roughly 32 ms −1. Our results indicate that vertical plasma drifts; ionospheric F2-layer peak height, and the critical frequency of F2-layer appear to be somewhat interconnected.