Radial Component of the Super-Low-Frequency Magnetic Field of a Horizontal Electric Dipole at Low Conductivity of the Ground Along the Propagation Path

Resumo

We study the super-low-frequency field of a grounded horizontal electric dipole on a high-latitude submeridional path having a length of up to 1000 km. Unlike most of the earlier works, this paper considers the case of wave propagation along the dipole axis, where the main component of the magnetic field is radial. The frequency dispersion of the ground conductivity under the source, which determines the coefficient of excitation of the Earth—ionosphere waveguide, is found from the measurements of the field at a distance of three heights of the ionosphere. Typical parameters of propagation of super-low-frequency waves are refined allowing for specific features of the path used in the experiment. The significance of allowing for ground conductivity as the radiation propagates along low-conductivity regions is demonstrated. The regions where one of the magnetic-field components is predominant are calculated in a polar coordinate system linked to the source, as well as the regions where the both components should be allowed for. The theoretical possibility of determining the phase velocity of the wave based on the ratios of the magnetic-field components measured at longer lengths is noted.