The paper provides a review of studies devoted to the peculiarities of the propagation of radio waves in the ionosphere in the area of the solar terminator, which is the only global and regular source of acoustic-gravitational waves and other disturbances of the ionosphere. It describes the results of theoretical works devoted to the study of perturbations created by the solar terminator in the area of the difference in the intensity of solar radiation in the atmosphere. The paper gives a review of experimental studies of the effects created by the solar terminator in the entire thickness of the atmosphere. These effects, in particular, include the multipath propagation of radio waves, their phase variations, and variations in amplitudes during the propagation of radio waves in the area of the solar terminator. In the interests of science and practice, a number of problems have been proposed for the further study of wave perturbations arising as a result of the movement of the temperature gradient at sunrise and sunset hours.
Investigation of the parameters of traveling ionospheric disturbances using a chirp ionosonde
