MUTUAL ELECTROMAGNETIC COUPLING OF LOOPS OVER A HOMOGENEOUS GROUND

Geophysics ◽  
1955 ◽  
Vol 20 (3) ◽  
pp. 630-637 ◽  
Author(s):  
James R. Wait
Keyword(s):  
Electromagnetic Coupling ◽  
Mutual Impedance ◽  
Geophysical Exploration ◽  
Electromagnetic Methods ◽  
Homogeneous Ground

Computations are presented for the mutual impedance between small wire loops situated on or over a semi‐infinite conductor. The results have application to electromagnetic methods of geophysical exploration.

MUTUAL ELECTROMAGNETIC COUPLING OF LOOPS OVER A HOMOGENEOUS GROUND—AN ADDITIONAL NOTE

Geophysics ◽  
1956 ◽  
Vol 21 (2) ◽  
pp. 479-484 ◽  
Author(s):  
James R. Wait
Keyword(s):  
Electromagnetic Coupling ◽  
Mutual Impedance ◽  
Additional Note ◽  
Homogeneous Ground

Further computations are presented for the mutual impedance between small wire loops over a semi‐infinite conductor. The cases considered are where the axes of the loops are parallel to the interface.

HIGH‐FREQUENCY ELECTROMAGNETIC COUPLING BETWEEN SMALL COPLANAR LOOPS OVER AN INHOMOGENEOUS GROUND

Geophysics ◽  
1972 ◽  
Vol 37 (6) ◽  
pp. 997-1004 ◽  
Author(s):  
James A. Fuller ◽  
James R. Wait
Keyword(s):  
Half Space ◽  
High Frequency ◽  
Electromagnetic Coupling ◽  
Current Source ◽  
Vertical Axis ◽  
Loop Current ◽  
Mutual Impedance ◽  
Multiplicative Factor ◽  
The Earth ◽  
Horizontal Electric Dipole

An integral formulation is given for the fields of a loop current source which is located over a horizontally stratified half‐space and has a vertical axis. The electrical properties of the half‐space vary exponentially with the depth into the earth. An asymptotic solution is developed for the case of source and observer on the interface but separated by a large numerical distance. The approximate solution is then used to determine the mutual impedance between two small loops and between the loop and a horizontal electric dipole, when the antennas are on the interface. It is found that the effect of stratification on the mutual impedance is represented approximately by a single multiplicative factor.

scholarly journals Reciprocity and mutual impedance formulas within lossy cavities

2005 ◽  
Vol 3 ◽  
pp. 91-97
Author(s):  
F. Gronwald ◽  
E. Blume
Keyword(s):  
Method Of Moments ◽  
Electromagnetic Interference ◽  
Electromagnetic Coupling ◽  
Rectangular Cavity ◽  
Dipole Antennas ◽  
Mutual Impedance ◽  
Antenna Theory

Abstract. We discuss the validity of reciprocity and mutual impedance formulas within lossy cavities. Mutual impedance formulas are well-known from antenna theory and useful to describe the electromagnetic coupling between electromagnetic interference sources and victims. As an example the mutual impedance between two dipole antennas within a lossy rectangular cavity is calculated from a system of coupled Hallén's equations that efficiently is solved by the method of moments.

Review of Geophysical Exploration on Mined-out Areas and Water Abundance

2019 ◽  
Vol 24 (1) ◽  
pp. 129-143
Author(s):  
Laifu Wen ◽  
Jiulong Cheng ◽  
Shaohua Huang ◽  
Jin Zhou ◽  
Yangchun Han ◽  
...  
Keyword(s):  
Geophysical Methods ◽  
Electromagnetic Method ◽  
Research Progress ◽  
Transient Electromagnetic Method ◽  
Water Abundance ◽  
Geophysical Exploration ◽  
Transient Electromagnetic ◽  
Seismic Methods ◽  
Electromagnetic Methods ◽  
Surface Borehole

With the increase in mining depth, the presence of goafs has become increasingly severe in mine safety. The accurate and effective detection of underground goafs and their water abundance is the key to ensure the safety of mine production. On the basis of the relevant research, this paper defines different goaf types from the perspective of geophysical exploration and discusses the geophysical prerequisites for goaf detection. DC methods, electromagnetic methods, seismic methods, and other geophysical methods on the ground and in the subsurface are reviewed and summarized using the method's principle, research status, and technical features. Research progress on the geophysical methods in goafs and their water abundance detection are introduced, including the electrical source short-offset transient electromagnetic method (SOTEM), the wave-field transformation and synthetic aperture of the transient electromagnetic method, and comprehensive detection. At the end of the paper, a direction for the development of coal mined-out areas and their water abundance detection is put forward, including information fusion technology, ground-airborne electromagnetic methods, magnetic resonance sounding (MRS), surface-borehole transient electromagnetic method, surface-borehole seismic methods, and seismic while tunneling technology. The application prospects of these methods are discussed, and the results of this study are expected to considerably improve the location precision and resolution of the goaf detection on the basis of the implications of these techniques.

SCALE MODEL EXPERIMENTS IN ELECTROMAGNETIC METHODS OF GEOPHYSICAL EXPLORATION

1951 ◽  
Vol 29 (4) ◽  
pp. 285-293 ◽  
Author(s):  
A. R. Clark ◽  
A. G. Mungal
Keyword(s):  
Magnetic Fields ◽  
Small Amplitude ◽  
Scale Model ◽  
Model Experiments ◽  
Geophysical Exploration ◽  
Electromagnetic Methods ◽  
Conducting Bodies ◽  
Alternating Magnetic Fields

A method of accurately measuring the phase as well as the amplitude of alternating magnetic fields of small amplitude has been devised and applied to the investigation of the response of conducting bodies placed in an electromagnetic field.The results have indicated how the position, dimensions, and dip of buried conductors may be evaluated.

Corrections to Millett’s table of electromagnetic coupling phase angles

Geophysics ◽  
1984 ◽  
Vol 49 (9) ◽  
pp. 1554-1555 ◽  
Author(s):  
R. J. Brown
Keyword(s):  
Half Space ◽  
Random Error ◽  
Electromagnetic Coupling ◽  
Inductive Coupling ◽  
Coupling Phase ◽  
Mutual Impedance ◽  
Phase Angles

Millett (1967) published tables of values of the mutual impedance due to inductive coupling between two collinear dipoles on a uniform, nonpolarizable half‐space. In the course of a recent study (Brown, 1984) I have noticed significant errors, of two different kinds, in the phase angles (ϕ) given by Millett (1967). One kind of error is evidently typographical in nature and occurs only twice, in the M = 3 table, for θ = .01 and .02. The tabled values apparently had their decimal points shifted one place. The second and more serious kind of error is an apparently random error within the range ±0.003 degrees. This is not significant for larger |ϕ|, say |ϕ| > 1 degree, but the values of |ϕ| in Millett’s tables go down to 0.006 degrees (down to 0.0045 degrees after correction) where such errors are clearly significant, particlarly if one is working with logarithmic quantities as is common.

A Novel Transmitting System for Electromagnetic Sounding Based on Tri-state Boost Converter

2019 ◽  
Vol 12 (6) ◽  
pp. 494-499
Author(s):  
Gang Li ◽  
Binren Zhang
Keyword(s):  
Simulation Model ◽  
Output Power ◽  
Basic Principle ◽  
Simulation Experiment ◽  
Dynamic Performance ◽  
Boost Converter ◽  
Electromagnetic Sounding ◽  
Important Method ◽  
Geophysical Exploration ◽  
Electromagnetic Detection

Background: Electromagnetic detection is an important method of geophysical exploration. The transmitting system is an important part of the electromagnetic detection equipment. Methods: The general topologies of a transmitting system for EM instrument are analyzed. The basic principle of EM detection is interpreted. In order to improve the output power and give consideration to the dynamic performance, an electromagnetic transmitting system based on the tri-state boost converter is proposed in this paper. Results: The principle of the proposed transmitting system is analyzed. The topology of the proposed transmitting system is illustrated and the working modes of tri-state boost converter are given. Conclusion: The simulation model is established and the simulation experiment is carried out to verify the feasibility of the new electromagnetic transmitting system.

Electromagnetic methods in nondestructive testing of materials

2003 ◽  
Vol 16 (1) ◽  
pp. 1-23
Author(s):  
Konstanty Gawrylczyk
Keyword(s):  
Sensitivity Analysis ◽  
Finite Elements ◽  
Nondestructive Testing ◽  
Eddy Current ◽  
Quality Evaluation ◽  
Leakage Flux ◽  
Electromagnetic Methods ◽  
Conducting Materials ◽  
Inductive Methods ◽  
Flux Probe

The article deals with progress in electromagnetic methods used for quality evaluation of conducting materials. The term "electromagnetic methods" covers the following areas: magneto-inductive methods, magnetic leakage flux probe method, magnetometer principle and eddy-current methods. For the aim of numerical cracks recognition the sensitivity analysis with finite elements was shown.

Sign in / Sign up

Export Citation Format

Share Document