Time-dependent behavior of tubes of F layer plasma is computed for tubes carried around several flow paths in the polar region. The flow paths are those proposed previously by Knudsen (1974). Ionization sources include direct and scattered solar photons and measured fluxes of precipitating energetic electrons. Computed electron concentrations are compared with measured concentrations from topside sounder data obtained in the same satellite pass as the energetic electron flux data. The following conclusions are drawn: The proposed convection pattern produces a tongue of F layer plasma over the polar cap with electron concentrations consistent with the measured concentrations. Had the F layer been assumed to be nonconvecting over the polar cap, the computed concentrations would have been a factor of 10 too small. Rapid convection of plasma across the cleft prevents significant increase in NmF2 at the cleft. Rapid convection must exist through the intense nightside auroral energetic particle precipitation zones, or a compensating electron loss mechanism must develop to prevent the buildup of an ionization ridge. A mid-latitude trough is formed by the proposed convection pattern with only normal F layer recombination processes operating. The low concentration in the trough is maintained by scattered solar EUV photons. The trough predicted by the numerical model is not observed in the topside sounder data.