Studies of ionospheric storms using a simple model

The ionospheric storm model is based on a heat source located at magnetic noon on Feldstein's auroral oval. The rotation of the earth produces an apparent motion of the source that is greater than the speed of the disturbance. This gives rise to a wake or front that sweeps over the globe and determines the onset time of the negative phase, which results from a change in chemical composition. At the front focusing will occur, which accounts for the sudden drop in electron density (or content) sometimes observed. Calculated diurnal variations of maximum electron density and height are in general agreement with the positive and negative phases of storms.