Researches On Mechanism Of SLF And ELF Wave Propagation In An Anisotropic Earth-Ionosphere Cavity

In recent years, the study of earthquakes, geological exploration, submarine navigation and communication technology all need further understanding of ultra-low frequency and extremely low frequency(SLF-ELF) electromagnetic wave propagation. So further study of extremely low frequency and its propagation mechanism is very important.In this paper, extremely low frequency electromagnetic wave propagation theory are dis-cussed. Firstly it repeats the previous work. The expressions of electromagnetic field generated by vertical electric dipole, vertical magnetic dipole and horizontal electric dipole are derived under the conditions that the earth and the ionosphere are ideal isotropic.As the frequency of SLF-ELF electromagnetic wave is very low, the ionosphere will show a clear anisotropic characteristics to SLF-ELF waves under the influence of Earth's magnetic field. Then further theoretical analysis to anisotropic properties of the ionosphere are done as well as the reflection characteristic and the impedance matrix.On the basis of the earth-ionosphere model, original simple isotropic ionosphere had been improved to anisotropic ionosphere affected by Earth's magnetic field. In such non-ideal con-ditions, the expressions of each component field generated by the vertical magnetic dipole are derived. Then with the expressions of the vertical electric dipole derived by predecessors, the expressions of the horizontal electric dipole are derived by using reciprocity theorem. Finally, program is compiled for computer simulation and some examples under the typical condition are given.