A theoretical technique for evaluating the time-dependent effects of general electrodynamic drifts in the F 2 layer of the ionosphere

A technique for solving the full global diffusion equation for the F2 layer, including electro­dynamic ‘E x B’ drift, is presented. This involves considering the form of the diffusion equation in axes moving with the electrodynamic ‘E x B’ drift. In addition, it is shown how the region of integration, which involves complicated dipole geometry, may be mapped on to a semi-infinite rectangle. The method is illustrated by calculating world curves of electron density for a simple model atmosphere in which the electrodynamic ‘E x B’ drift and the electron production are time dependent and the electron loss coefficient is time indepen­dent. The calculations are compared with previous experimental results and confirm electrodynamic lifting as one of the major factors controlling the dip equatorial F2 layer and the associated trough of ionization as suggested by D. F. Martyn.