Properties of the Subauroral Electron Temperature Enhancement

In the nightside subpolar region, energy transfer from the inner magnetosphere causes a significant increase in the electron temperature of the upper ionosphere. DE2 data are used to investigate the storm behavior and mean properties of this remarkable feature. First the location of the temperature enhancement and its dependence on geomagnetic activity are determined. Next the variation of the magnitude of the temperature increase with altitude and geomagnetic activity is documented. Finally, a superposed epoch type of averaging procedure is used to derive the mean latitudinal profile of the temperature enhancement. Our results are compared with the properties of the electron temperature enhancement beneath the magnetospheric cleft.