The outer ionosphere

The results from ionospheric beacon observations are compared with the theory of F-layer and outer ionosphere. Near sunspot minimum the total electron content up to 1000 km at medium latitudes is 1–2 × 10¹⁷ m^-2 in the afternoon and about 0.3 × 10¹⁷ m^-2 at night. The diurnal and latitudinal variations are more irregular during summer than during winter. Near sunspot maximum the respective values are about 1.5 × 10¹⁷ m^-2 at night, 6–7 x 10¹⁷ m^-2 near winternoon, 4 × 10¹⁷ m^-2 near summernoon.The complete theory of diffusion in a multi-ion plasma gives very complicated expressions. Simpler approximations can be found respectively. Some models were calculated numerically and the dependence of the total electron on the parameters of the balance equation is investigated.Comparison with experimental results shows, that some main features of the diurnal and latitudinal variations of the total electron can be explained. The seasonal anomaly, the slow decrease in the late night hours and the large increase toward equator cannot be explained without additional assumptions.