We have extended our high-latitude, ionospheric, dynamic model to include N+ in addition to the ions NO+, O2+, N+2, and O+. The ion He was also included but altitude profiles of this ion were obtained from our previous polar wind study. We have further improved our model by updating the various chemical reaction rates and by including the latest solar EUV fluxes measured by the Atmosphere Explorer satellites, the most recent MSIS model of the neutral atmosphere (N2, O2, O, and He) and the latest empirical model of atomic nitrogen. The improved model was used to study th solar cycle, seasonal, and geomagnetic activity variations of the daytime high-latitude F layer. Both zonal and meridional convection electric fields were considered. Without allowance for electric fields, th peak O+ and N+ densities varied by an order of magnitude and the altitudes of the peaks varied by about 100 km over the range of geophysical conditions studied. Convection electric fields can also produce about an order of magnitude change in the O+ and N+ densities. These electric field induced changes could either assist or oppose th solar cycle, seasonal, and geomagnetic activity variations depending on the ionospheric conditions. In general, N+ was the second most abundant ion in the upper F region, but there were cases when He+ was more abundant than N+ even though He+ was in a state of outflow. Also, we speculate that at time, N+ can be the dominant ion in the upper F region. |