“…Studying the propagation of radio waves in the super low (SLF) and extremely low frequency bands (ELF) (30-300 and 3-30 Hz, respectively, in the International Telecommunication Union designation) in the anisotropic three-dimensional (3D) Earth-ionosphere waveguide is of interest both from the theoretical standpoint and for the practical use in the radiophysical and geophysical applications. In our previous works [1], [2], we considered the influence of the ionosphere on the low-frequency field in the vicinity of the source, i.e., within distances shorter than or comparable to the waveguide height. It was established that the field structure in this region is mainly determined by the conductivity of the lithosphere.…”