Modeled F region response to auroral dynamics based upon Dynamics Explorer auroral observations

Abstract

Auroral images from the Dynamics Explorer 1 (DE 1) scanning auroral imager have been combined with in situ auroral precipitation data from the DE 2 low altitude plasma instrument to form a time‐dependent global auroral energy flux model. This model has both good time (12 min) and spatial (100 km) resolution compared to that currently available for global scale ionospheric and thermospheric modeling. The development and comparison of this model with others are discussed. Data from an aurorally active period, November 25, 1981, are presented and used as a case study for this model. Using a global ionospheric model, the effect of the DE auroral model is contrasted with that of a conventional empirical auroral energy flux model. Major differences in the modeled F region ionosphere are predicted from this comparative study. Specifically, F region densities differ by factors of two to four, while density boundary locations differ by up to 5° in latitude. The results indicate that “pixel size” auroral fine‐structure must be included in the global ionosphere and thermosphere models when they are tested against specific ground‐based or satellite data sets if an unambiguous result is to be obtained. The longer time constants of the F region are not enough to smooth‐out the auroral (spatial and temporal) dynamics.