Further investigation of the interference minimums in the low-frequency electromagnetic fields produced by a submerged vertical magnetic dipole

Radio Science ◽  
1990 ◽  
Vol 25 (4) ◽  
pp. 339-347 ◽  
Author(s):  
A. S. Inan ◽  
A. C. Fraser-Smith
Keyword(s):  
Magnetic Dipole ◽  
Electromagnetic Fields ◽  
Low Frequency ◽  
Vertical Magnetic Dipole

scholarly journals Quasi-Static Solution for ELF/SLF near-Zone Field of a Vertical Magnetic Dipole near the Surface of a Lossy Half-Space

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Lina He ◽  
Tong He ◽  
Kai Li
Keyword(s):  
Magnetic Dipole ◽  
Numerical Solutions ◽  
Low Frequency ◽  
Analytical Techniques ◽  
Static Solution ◽  
Static Approximation ◽  
Near Zone ◽  
Vertical Magnetic Dipole ◽  
Validity Limit ◽  
Zone Field

Dipole antennas over the boundary between two different media have been widely used in the fields of geophysics exploration, oceanography, and submerged communication. In this paper, an analytical method is proposed to analyse the near-zone field at the extremely low frequency (ELF)/super low frequency (SLF) range due to a vertical magnetic dipole (VMD). For the lack of feasible analytical techniques to derive the components exactly, two reasonable assumptions are introduced depending on the quasi-static definition and the equivalent infinitesimal theory. Final expressions of the electromagnetic field components are in terms of exponential functions. By comparisons with direct numerical solutions and exact results in a special case, the correctness and effectiveness of the proposed quasi-static approximation are demonstrated. Simulations show that the smallest validity limit always occurs for component H2z, and the value of k2ρ should be no greater than 0.6 in order to keep a good consistency.

ELECTROMAGNETIC FIELDS OF AN OSCILLATING MAGNETIC DIPOLE OVER AN ANISOTROPIC EARTH

Geophysics ◽  
1968 ◽  
Vol 33 (2) ◽  
pp. 346-353 ◽  
Author(s):  
Ajit K. Sinha
Keyword(s):  
Wave Propagation ◽  
Electromagnetic Wave ◽  
Magnetic Dipole ◽  
Electromagnetic Fields ◽  
Isotropic Medium ◽  
Electromagnetic Wave Propagation ◽  
Vector Potentials ◽  
The Earth ◽  
Longitudinal Conductivity ◽  
Vertical Magnetic Dipole

The problem of electromagnetic wave propagation from an oscillating magnetic dipole placed over a uniaxially anisotropic earth has been considered. Formal expressions for the vector potentials inside the earth have been derived. It has been shown that for a vertical magnetic dipole, the field components are identical to those in the case of an isotropic medium in which the conductivity is the “horizontal or longitudinal conductivity.” For a horizontal dipole, directed along the x axis, it has been shown that the vector potential inside the earth will have a y component as well as x and z components. Formal expressions for the vector potentials in air have been obtained for the case of a horizontal magnetic dipole. However when the conductivity of air is considered to be negligibly small, the field components are not affected by the anisotropy.

scholarly journals Inductive sounding of layered earth

2020 ◽  
pp. 21-31
Author(s):  
Arzamastsev Evgenii ◽  
◽  
Astafiev Pavel ◽  
Baidikov Sergei ◽  
Konoplin Aleksei ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Dipole ◽  
Transmission Lines ◽  
Oil And Gas ◽  
Experimental Studies ◽  
Low Frequency ◽  
Information Value ◽  
Layered Earth ◽  
Dipole Magnetic Field ◽  
Vertical Magnetic Dipole

Research aim. The research results in the development of a technology of continuous multi-frequency induction profiling measuring magnetic field components on long survey routes and detailed elaboration of sections by means of remote induction soundings. Research methodology. Theoretical and experimental studies of magnetic field components change patterns of harmonic vertical magnetic dipole over non-uniform layered earth. Mathematical simulation of harmonic vertical magnetic dipole magnetic field in non-uniform layered earth. Analysis of results. Information value of harmonic vertical magnetic dipole magnetic field components characteristics in low-frequency induction zone has been shown when studying non-uniform geoelectric sections together with the obtained results correspondence to the type of the non-uniform section when carrying out remote inductive sounding. 30 "Izvestiya vysshikh uchebnykh zavedenii. Gornyi zhurnal". No. 4. 2020 ISSN 0536-1028 Scope of results. for extended sections of route research (road and railway, oil and gas pipelines, power transmission lines, etc.) process sequence of vertical magnetic dipole magnetic field characteristics measurement has been determined to determine geoelectric properties of a layered section by means of continuous multi-frequency profiling and determination of homogeneous sections of medium structure with their detailing by discrete analysis by the method of remote inductive sounding.

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