Aeronomic problems arising in the interpretation of electron density profiles in the F region

In the F region the balance equation for electron density, including ionization, electron losses and transfer of charged particles, is mainly dependent on the balance of positive ions of atmoic oxygen which are produced by photoionization. If the data are introduced into the balance equation and compared to the profiles of the electron density found by means of ionospheric sounding at middle latitudes, then considerable vertical movements of the ionospheric plasma in the F region must be assumed. These vertical movements vary during the day and especially during a solar eclipse. Diffusion alone is not sufficient to explain these phenomena.