Model of mid-and low-latitude F region ionosphere and protonosphere

Abstract

The coupled continuity and momentum equations of O+ and H+ ions in the F region and the protonosphere are solved for a mid-latitude station (Arecibo) and a low-latitude station (Jicamarca) to investigate the diurnal behavior of the peak electron density NmF2, the height of the peak HmF2, the O+ - H+ transition height Htr and the transition level ion density Ntr·The effects of the neutral wind on the NmF2, HmF2, Ntr and Htr curves above Arecibo are more important than and generally in the opposite direction of those of a sinusoidal electromagnetic drift. The electromagnetic drift plays a far-reaching role in shaping the ionospheric and protonospheric profiles at Jicamarca. An upward drift that peaks during the day produces a 'valley' in the NmF2 curve, while an upward drift that stays constant during most of the day produces a 'plateau'. The nighttime decay in NmF2 is due to the combined effects of a slow downward drift and chemical recombination. A nocturnal increase in NmF2 is due to a sufficiently large downward drift when the resultant 'squeezing' of the field tubes overcomes the O+ loss rate. The diurnal variations of HmF2 and Htr tend to follow that of the upward drift velocity pattern, with gradients somewhat smoothed. A downward reversal of the drift at sunset causes an enhancement in the post-sunset Ntr·Finally, the applicability of the model to the study of the total electron content measurements of the ATS-6 radio beacon experiments at Ootacamund is demonstrated. by comparing with the observed values, the probable drift velocities over Ootacamund are determined for October and December, 1975. The drift velocity patterns show broad similarities with those observed over Jicamarca.