Processes Controlling Ionization Distribution in the F2 Region of the Ionosphere

Abstract

It has been known for more than 20 years that the morphology of the principal (F2) region of the ionosphere is complex, and inexplicable in terms only of solar ionizing radiation and recombination. The hypothesis was advanced (Martyn 1947) that movement, and especially vertical movement, of F2 ionization was the main reason why the morphology of this region differed so profoundly from that of the lower regions E and F1, which conform closely with Chapman's well-known theory. A principal cause of movement of F2 ionization was held to be the drift occasioned by the electrodynamic forces and winds associated with the ionospheric electric current systems whose existence is manifested by the daily magnetic variations at the ground. There is now considerable evidence, both theoretical and observational, to show that this view may be essentially correct.