Search

In this paper, the approximate formulas have been derived for ELF electromagnetic field in near zone from a horizontal electric dipole on the surface of sea water and one-dimensional anisotropic rock boundary. The computational scheme exploits the concept of quasi-static approach for ELF near-field approximations. Specifically, the integrands of Fourier-Bessel representations are approximated by adopting Maclaurin's Expansion where the ratio of wave numbers for rock and sea approaches zero. The approximated solution is in good agreement with the available experimental data. [ABSTRACT FROM AUTHOR]

In this paper, the electromagnetic pulses have been investigated based on the theory of wave-hop propagation. The approximate formulas are obtained for the electromagnetic field of a vertical magnetic dipole in the presence of an Earth-ionosphere waveguide. Based on the results obtained, the approximate formulas are derived readily for the ground wave and sky waves due to horizontal electric dipole excitation by using a reciprocity theorem. The corresponding computations and discussions are carried out specifically by analogy with those generated by a vertical electric dipole with the formulas in CCIR's recommendation. It is shown that the sky wave pulses would interfere at certain distances and occur by different time-delays. [ABSTRACT FROM AUTHOR]