Space plasma environment at high and polar latitudes by the Cosmos 1809 satellite topside sounder data

The paper presents results of Cosmos 1809 satellite topside sounder data processing. Analogous records of topside ionograms collected during the icebreaker Sibir´ cruise to the North Pole in 1987 were transformed in the digital ionograms dataset for the more than 90 cross-pole passes (more than 8000 ionograms). For different plasma conditions (f_p>;f_he and f_p<;f_he) we demonstrate the power of topside sounding using not only traditional critical frequency and vertical profile parameters but also the plasma resonances distribution, natural emissions registered both on ionograms and on dynamic spectrograms created from AGC records which permit to map magnetospheric structures.