The effect of a variable electron temperature on the equatorial electron density distribution in the upper ionosphere

By incorporating a model for the measured electron temperature distribution at the magnetic equator in the isothermal and temperature equilibrium theory of Goldberg, Kendall and Schmerling, it has been possible to gain further insight into the behavior of the equatorial geomagnetic anomaly under steady-state and equinoctial conditions. In particular, it is shown that the measured deviation from thermal equilibrium in the bottomside ionosphere is very influential in allowing extension of the previous theoretical description of the geomagnetic anomaly well into the bottomside ionosphere and to higher latitudes than originally applicable. For completeness the effect of gravitational variation is now included, but it is shown that this effect alone contributes only minor improvements to the original results. Finally, several less common properties, in the behavior of the geomagnetic anomaly are investigated, and it is shown under what conditions these secondary effects will occur.