Theoretical simulation of O⁺ and H⁺ densities in the Indian low latitude F-region and comparison with observations

Abstract. The O⁺ and H⁺ ion density distributions in the Indian low latitude F-region, within ± 15° magnetic latitudes, are simulated using a time dependent model developed on the basis of solution of the plasma continuity equation. The simulated ion densities for solar minimum June and December solstices are then compared with ionosonde observations from the period 1959–1979 and measurements made by the Indian SROSS C2 satellite during 1995–1996 at an altitude of ~ 500 km. The simulated O⁺ density has a minimum around pre-sunrise hours and a maximum during noontime. H⁺ density is higher at nighttime and lower during the day. The simulations reproduced the well-known equatorial ionization anomaly (EIA) observed in electron density at the peak of the F2-region in the Indian low latitude sector during solar minimum. In situ measurement of O⁺ density by the SROSS C2, however, showed a single peak of ionization around the equator.

Key words. Ionosphere (equatorial ionosphere; modeling and forecasting)