ИСТИНА

We describe the experiments carried out in 2009-2011 on the modification of the midlatitude ionosphere by powerful HF-heating from the Sura facility near N. Novgorod (Russia). We analyze the responses of the GPS/GLONASS and Parus/Tsikada satellite radio signals to the heating-induced disturbances in electron density. We study the variations in the total electron content (TEC), which are proportional to the reduced phase of navigational signals passed through the heated area and present the examples of identifying the variations in TEC (including determination of their amplitudes and the parameters of temporal behavior) caused by HF heating. It is found that the TEC spectra contain frequency components corresponding to the modulation periods of the heating wave. We also present the spatial structure of the ionospheric disturbances generated by the Sura heating facility imaged using the method of low-orbital radio tomography.