Subsurface electromagnetic fields of a circular loop of current located above ground

Wait, James R.; Spies, Kenneth P.

doi:10.1109/tap.1972.1140232

Cited by 33 publications

(46 citation statements)

References 3 publications

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“…It is instructive at this point to compare the expressions for the fields developed here to those in [31] ‡ , which gives explicit expressions for fields in a conducting half-space due to a finite circular loop. From Equations 9 -11, the expressions for the fields at a point (ρ 0 ,φ 0 , -d) in the soil having parameters σ 1 and χ + iχ can be written, neglecting displacement currents and using definitions and normalisations similar to those in [31], as:…”

Section: Fields In Soilmentioning

confidence: 99%

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A preliminary investigation of the effects of soil electromagnetic properties on metal detectors

Das

2004

Detection and Remediation Technologies for Mines and Minelike Targets IX

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Some soils can adversely affect the operation of sensitive metal detectors widely used to detect buried landmines. Although there has been some related work in geophysics, researchers in metal detection techniques, until very recently, seem to have largely ignored the issue of problem soil. As a result, rigorous scientific investigations of how soil electromagnetic properties may affect the operation of metal detectors are lacking. Thus, there is a need for theoretical and experimental studies to clarify which electromagnetic properties are important and to what extent they affect the performance of metal detectors of various designs. The paper presents a systematic analytical framework, based on existing work in geophysics and non-destructive testing, for studying the effects of soil electromagnetic properties on the functioning of metal detectors. For this initial study the burial medium is modelled as a half-space. While soil electrical conductivity has been assumed to be real and independent of frequency, soil magnetic susceptibility has been modelled as complex and frequency dependent. Simplified versions of the analysis techniques have been applied to three selected cases of practical importance, namely, non-conducting soil with constant susceptibility, non-conducting soil with frequency-dependent susceptibility and non-magnetic soil with constant conductivity. Results from a preliminary analysis of even these simple cases explain a number of previous experimental observations, for example, the greater influence of magnetic properties than of electrical conductivity on the performance of metal detectors.

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Section: Fields In Soilmentioning

confidence: 99%

“…From Equations 9 -11, the expressions for the fields at a point (ρ 0 ,φ 0 , -d) in the soil having parameters σ 1 and χ + iχ can be written, neglecting displacement currents and using definitions and normalisations similar to those in [31], as:…”

Section: Fields In Soilmentioning

confidence: 99%

A preliminary investigation of the effects of soil electromagnetic properties on metal detectors

Das

2004

Detection and Remediation Technologies for Mines and Minelike Targets IX

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“…In [1], it was proposed for communication from above ground to observation points within coal mines. In this paper, the interactions of electromagnetic field, produced by a current-excited small loop, with lossy and lossless materials are investigated.…”

Section: Introductionmentioning

confidence: 99%

A Transient, Axisymmetric Formulation for Modeling of Composite Materials

Lee

Ida

1990

Review of Progress in Quantitative Nondestructive Evaluation

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“…The problem of the fields of circular coils in the vicinity of metal sheets has been studied by previous authors [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. This work has, in general, concentrated on frequencies where the metal sheet appears thin, i.e.…”

Section: Introductionmentioning

confidence: 99%

“…its thickness is of the same order as the skin depth. Related problems have been studied [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20], and the general method used is the formulation of the problem in terms of a vector wave equation and the solution of this with approximate approximations. This is the method adopted here, solving first for the fields due to a single simple circular coil and then extending the results to the transfer impedance between two simple coils and finally to thick solenoids.…”

Section: Introductionmentioning

confidence: 99%

Transfer impedance between circular coils separated by thick nonferrous metal sheets

Ball

Staniforth

1981

IEE Proc. A Phys. Sci. Meas. Instrum. Manage. Educ. Rev. UK

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Subsurface electromagnetic fields of a circular loop of current located above ground

Cited by 33 publications

References 3 publications

A preliminary investigation of the effects of soil electromagnetic properties on metal detectors

A preliminary investigation of the effects of soil electromagnetic properties on metal detectors

A Transient, Axisymmetric Formulation for Modeling of Composite Materials

Transfer impedance between circular coils separated by thick nonferrous metal sheets

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