ON THE EXCITATION OF THE EARTH IONOSPHERE WAVE-GUIDE BY PULSED ELF SOURCES

A theoretical treatment is given of the problem of the excitation of ELF pulses by lightning discharges in the Earth-ionosphere waveguide. This is done for the GREIFINGER and GREIFINGER [(1978) Radio Sci. 13, 831 and (1979) Radio Sci. 14, 998] approximation of ELF wave propagation. We have obtained characteristic waveforms of the pulses excited by various model sources under different conditions. The dependence of ELF pulse delay on propagation distance is investigated; this is found to be close to linear at distances similar to or less than 10.000 km. Peculiarities of the form of the ELF pulse excited by a horizontal, or nearly horizontal, lightning discharge have also been analyzed.