LONGITUDINAL INHOMOGENEITIES OF THE IONOSPHERE ELECTRON CONCENTRATION OF THE EURASIA MIDDLE LATITUDES AND THEIR RELATION TO THERMOSPHERIC GAS DISTURBANCES DURING GEOMAGNETIC STORMS UNDER EQUINOX CONDITIONS

Variations of ionospheric and thermospheric parameters in the Northern Hemisphere were studied based on the analysis of data from the mid-latitude chain of Eurasian ionosondes during periods of strong geomagnetic disturbances of the 24th solar activity cycle under equinox conditions. During the main phase of all analyzed magnetic storms over the middle latitudes of Eurasia, a transition from a positive to a negative ionospheric storm effect was observed. The effect of a negative ionospheric storm during the recovery phase was caused by the formation of vast areas of atmospheric gas with a reduced [O]/[N2] concentration ratio over the region of mid-latitudes of Eurasia.