ИСТИНА

The observations by the partial reflection method of the lower polar ionosphere above the settlement Tumanny in region (69.0° N, 35.7° E) during strong X-class solar flares from 15 to 20 January are presented. In these events significant variations of the vertical structure of the polar ionosphere were revealed. The variations displayed in decrease of an altitude of the ionosphere bottom by 25 km and in increase of electron concentration at the heights of 50-60 km by two orders of magnitude. Ionospheric effects of the flares were accompanied by the strengthened absorption of middle and short radiowaves as well as by splashes of cosmic radioemission. It was shown experimentally that the sources of the observed ionospheric disturbances were solar proton fluxes with energy up to 80 MeV and powerful flares of X-ray solar emission.