Concise theory of radio transmission in the Earth‐ionosphere wave guide

Wait, James R.

doi:10.1029/rg016i003p00320

Cited by 7 publications

(1 citation statement)

References 24 publications

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“…Waston [18], [19] obtained the sum of series of Hankel function and spherical Bessel function of the electromagnetic field transmitted from and received by the earth surface, and changed the form of the sum of series into that of the integral solution by way of the residue theorem. Wait [20]- [24] analyzed the theory of ELF electromagnetic wave propagation in planar earth-ionospheric waveguides and spherical waveguides, and solved the problem of the electromagnetic field in the inhomogeneous medium. Due to the existence of spherical waveguides, the electromagnetic field resonates within the range of ELF.…”

Section: Introductionmentioning

confidence: 99%

Study on Electrical Properties of Multilayered Spherical Earth by Wireless Electromagnetic Method

Gao

Ma³

et al. 2021

IEEE Access

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The wireless electromagnetic method (WEM), a new method combining geophysics and radio physics, can be used for seismic monitoring, ionospheric structure exploration and electrical structure detection within a depth of 10m underground. As the wavelength of an electromagnetic wave can be equal the circumference of the earth, the influence of ionosphere and earth curvature on electromagnetic waves shall be considered. Considering that the earth is a multi-layer geoelectric medium, a multi-layer ''Earth-ionosphere'' model is established to simulate the electromagnetic field more accurately in the actual complex underground structure. By combining the W.K.B method and the impedance recursion method, we initially obtained the response formula under such a model, calculated the Schumann Resonance within the low frequency range of 1-30Hz, and verified the correctness of the algorithm proposed by this paper; we subsequently obtained the propagation characteristics and the frequency characteristics of the electromagnetic field under different electrical structures by simulation and calculation, and analyzed the propagation law of the electromagnetic field at different times and at different equivalent heights of the ionosphere. The results revealed that the influence of the ionosphere and the earth curvature must be accounted for in large-scale deep detection, and different underground structures and the equivalent heights of ionosphere at different times may lead to differences in the value of the electromagnetic field. Therefore, the multi-layered spherical ''Earthionosphere'' model can better meet the requirements of high-power WEM for the forward calculation of underground complex electrical structure detection and assist the refined exploration by such a method. INDEX TERMS Extremely low frequency electromagnetic method, spherical coordinate system, ''earth-ionosphere'' model, multilayered sphere, refined electrical structure.

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Section: Introductionmentioning

confidence: 99%

Study on Electrical Properties of Multilayered Spherical Earth by Wireless Electromagnetic Method

Gao

Ma³

et al. 2021

IEEE Access

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VLF waves at satellite altitude to investigate Earth electrical conductivity

Leye

Tarits

2015

Radio Science

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At and near the Earth surface, electromagnetic (EM) fields radiated from VLF transmitters are commonly used in geological exploration to determine the shallow Earth conductivity structure. Onboard satellites such as DEMETER, the electric and magnetic sensors detect the VLF signal in altitude. While we know for surface measurement that the VLF EM field recorded at some distance from the transmitter is a function of the ground conductivity, we do not know how this relationship changes when the field is measured at satellite altitude. Here we study the electromagnetic field radiated by a vertical electric dipole located on the Earth surface in the VLF range and measured at satellite altitude in a free space. We investigate the EM field as function of distance from the source, the height above the Earth surface, and the electrical conductivity of the Earth. The mathematical solution in altitude has more severe numerical complications than the well‐known solutions at or near the Earth surface. We test most of the solutions developed for the latter case and found that direct summation was best at several hundred kilometers above the Earth. The numerical modeling of the EM field in altitude shows that the field remains a function of Earth conductivity. The dependence weakens with altitude and distance from the transmitter. It remains more important for the electric radial component.

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The method of multiply reflected waves in the problem of the propagation of electromagnetic waves in regular waveguides (a review)

Makarov¹,

Fedorova²

1982

Radiophys Quantum Electron

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Concise theory of radio transmission in the Earth‐ionosphere wave guide

Cited by 7 publications

References 24 publications

Study on Electrical Properties of Multilayered Spherical Earth by Wireless Electromagnetic Method

Study on Electrical Properties of Multilayered Spherical Earth by Wireless Electromagnetic Method

VLF waves at satellite altitude to investigate Earth electrical conductivity

The method of multiply reflected waves in the problem of the propagation of electromagnetic waves in regular waveguides (a review)

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