Hydrogen & Oxygen Ion Densities & Fluxes In Low & Midlatitude Topside Ionosphere

Abstract

The daytime altitudinal variation of ion diffusion flaxes and their influence on H⁺ and O⁺ densities in the topside ionosphere in the low and midlatitudes are investigated theoretically, taking into account the ionosphere protonosphere coupling. The H⁺ density is considered to be in chemical equilibrium at altitudes below 600 km and in dynamical equilibrium at altitudes above 600 km. Using the observed 0⁺ ion densities, recently derived neutral hydrogen densities, and electron and ion temperature profiles, the transport fluxes of O⁺ and H⁺ ions are evaluated taking into consideration the geomagnetic field geometry. It has been shown that the relative sizes of the magnetospheric field tubes in the low and midlatitudes control the density variation in the topside ionosphere and produce lower proton densities in the midlatitudes compared to low latitudes. Also, the diffusive equilibrium profiles differ considerably from the dynamical equilibrium profiles.