Seasonal features in the main ionospheric trough formation

The main ionospheric trough (MIT) is a latitudinal narrow and longitudinal elongated feature in the F-region of the ionosphere in subauroral latitudes. The trough is characterized by a decrease in total ion density from medium towards subauroral latitudes followed by a region of increased plasma density in the auroral zone. Within the magnetohydrodynamic approximation at given conditions of the thermosphere the ionic component of the ionospheric plasma can be described by the atomic ion density and velocity, electron and ion temperatures. The solution of this problem has been realized by Kolesnik and Golikov using a time-dependent three-dimensional numerical model of the high-latitude ionosphere at F region altitudes. Some results on the calculation of the atomic oxygen ion density distribution and on the formation of the F-region ionization trough in winter period have been published in our previous works. In this report new development of the above-described model and calculation of the electron density in the MIT at different time are presented and discussed