General expressions for the electromagnetic fields of homogeneous TM-type plane waves at a skew angle of incidence upon an inclined anisotropic half-space are derived. Previous analyses have only considered fields of homogeneous plane waves in the problems of a laterally anisotropic half-space, and not the problem of an inclined anisotropic half-space. Previous analyses also have assumed that the linear polarization of the incident magnetic field is maintained, regardless of the anisotropy present. The results presented in this paper have shown that while this assumption is valid only for the magnetic field, the electric field is elliptically polarised in the anisotropic half-space. This is demonstrated through a model study and experimental verification at VLF. The solutions obtained converge on the expected values for the special cases presented by other authors.
1. Boerner, D. E., R. D. Kurtz, and A. G. Jones, "Orthogonality in CSAMT and MT measurements," Geophysics, Vol. 58, 924-934, 1993. doi:10.1190/1.1443483
2. Rankin, D. and I. K. Reddy, "Polarization of the magneto-telluric fields over an anisotropic earth," Pure App. Geophys., Vol. 78, 58-65, 1970. doi:10.1007/BF00874773
3. Thiel, D. V., M. J. Wilson, and C. J. Webb, "A surface impedance mapping technique based on radiation from discrete lightning discharges," Geoexpl., Vol. 25, 163-172, 1988. doi:10.1016/0016-7142(88)90011-7
4. Wait, J. R., Electromagnetic Waves in Stratified Media, 2nd edition, Permagon Press, Oxford, 1970.
5. Galejs, J., "Horizontally orientated antennas in the presence of an anisotropic ground," Radio Sci., Vol. 4, 1047-1059, 1969.
6. Parks, G. S., G. H. Price, A. L. Whiston, and H. W. Parker, "Measurements of VLF wavefront components over long paths," Stanford Res. Inst., No. 3590, 1964.
8. Arcone, S. A. and A. J. Delaney, "Low frequency surface impedance measurements at some glacial areas in the United States," Radio Sci., Vol. 15, 1-9, 1980.
9. Fischer, G., B. V. Le Quang, and I. Muller, "VLF ground surveys: a powerful tool for the study of shall two-dimensional structures," Geophys. Prosp., Vol. 31, 977-991, 1983. doi:10.1111/j.1365-2478.1983.tb01100.x
10. Thiel, D. V., "One-dimensional surface impedance measurements above an anisotropic earth," Explor. Geophys., Vol. 15, 43-46, 1984.
11. Ramaprasada Rao, I. B., R. R. Mathur, and N. S. Patangay, "A study on the possibility of assessing anisotropy due to 2-D structures from VLF-EM data," Deep Electromagnetic Exploration, 607-615, 1998.
12. Chetaev, D. N. and B. N. Belen'kaya, "The electromagnetic field of an inhomogeneous plane wave in a horizontally inhomogeneous half-space," Phys. Solid Earth, Vol. 7, 212-213, 1971.
13. Chetaev, D. N. and B. N. Belen'kaya, "Field of inhomogeneous plane electromagnetic waves at the surface of an anisotropic halfspace," Phys. Solid Earth, Vol. 8, 535-538, 1972.
14. Chetaev, D. N., "Teoriia estestvennogo electromagnitnogo polia Zemli," Estestvennoye Electromagnitoe Pole i Issled Ovaniya Vnutrennego Stroeniya, 15-39, 1971.
15. Tikhonov, A. N., "The propagation of a continuous electromagnetic wave in a laminarly anisotropic medium," Sov. Phys. Dokl., Vol. 4, 566-570, 1959.
16. Chetaev, D. N., "On electromagnetic potentials in anisotropic layered media," Phys. Solid Earth, Vol. 2, 651-657, 1966.
17. Wilson, G. A. and D. V. Thiel, "Conductivity and resistivity tensor rotation for surface impedance modeling of an anisotropic half-space," Radio Sci., Vol. 37, 2002. doi:10.1029/2001RS002535
18. Berdichevsky, M. N. and V. I. Dmitriev, "Magnetotellurics in the context of the theory of ill-posed problems," Soc. Explor. Geophys., 2002.
19. Nichols, W. J. F., "Surface and borehole geophysical analysis of structures within the Callide Basin, Eastern Central Queensland," MAppSc thesis, 2001.
20. Thiel, D. V., "On measuring electromagnetic surface impedance â€” discussions with Professor James R. Wait," IEEE Trans. Antennas Propagat., Vol. 48, 1517-1520, 2000. doi:10.1109/8.899667
21. Thiel, D. V. and I. J. Chant, "Ionospheric induced very lowfrequency electric field wavetilt changes," Geophysics, Vol. 47, 60-62, 1982. doi:10.1190/1.1441282