Wave-like processes in the ionosphere under quiet and disturbed conditions. 1. Kharkov incoherent scatter radar observations

Wave-like disturbances (WDs) with periods of 30–120 min at altitudes of 125–500 km (100–1000 km in individual experiments) have been studied. The measurements of total duration more than 400 h have been performed under the conditions of a quiet ionosphere as well as during magnetic and ionospheric storms and two solar eclipses. It has been indicated that WDs exist almost permanently in the ionosphere. The effect of powerful energy sources leads to a change in the WD character and to variations in the WD spectral composition and amplitudes. The latter substantially vary during a day and depending on the disturbance of the ionosphere. The WD relative amplitudes vary from several percent to several tens of percent.