Lower polar ionosphere during a solar flare as revealed from radiooccultation data in satellite-to-satellite links

It is shown that there are typical variations in the amplitude and phase of decimetric radio waves in satellite-to-satellite links due to variations in the polar ionosphere structure. The altitude profiles of the electron number density and vertical size of the ionospheric sporadic structures in the nighttime polar regions during the period of intense solar activity in October 25 to November 09, 2003 are estimated. Correlation between the the ionosphere characteristics and the solar-wind parameters is discussed. It is noted that the effect of energetic-particle precipitation due to the influence of shock waves of the solar wind is the main factor responsible for strong variations in the nighttime polar ionosphere. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 52, No. 3, pp. 181–191, March 2009.