AN INVESTIGATION OF THE NIGHT-TIME INCREASES OF THE PLASMA DENSITY IN THE MIDDLE-LATITUDE IONOSPHERIC F2-LAYER BY THE MATHEMATICAL MODELING METHOD

Abstract. The forming mechanism of the night-time increases of the plasma density in the middle-latitude ionospheric F2-layer has been investigated using the global numerical Upper Atmosphere of the Earth Model (UAM). The model calculation results show that main cause of the occurrence of these increases is the equatorward thermospheric wind. The dependence of these increases on seasons and solar activity has been investigated. The enhanced plasma density regions can extend up to the heights of the plasmasphere of the Earth. The electromagnetic drift influences on the latitudinal location of the high-latitude sides of these regions, moving them to the lower latitudes.