ELECTROMAGNETIC FIELDS OF A SHORT ELECTRIC DIPOLE IN FREE SPACE – REVISITED

General classical equation of spin motion is explicitly derived for a particle with magnetic and electric dipole moments in electromagnetic fields. Equation describing the spin motion relative to the momentum direction in storage rings is also obtained.

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On modeling a well casing for resistivity and induced polarization

Geophysics ◽

10.1190/1.1441619 ◽

1984 ◽

Vol 49 (11) ◽

pp. 2061-2063 ◽

Cited By ~ 5

Author(s):

James R. Wait

Keyword(s):

Electrical Properties ◽

Electric Dipole ◽

Free Space ◽

Eddy Currents ◽

Interfacial Polarization ◽

Induced Polarization ◽

Mutual Impedance ◽

The Earth ◽

Horizontal Electric Dipole ◽

Displacement Currents

In a previous communication I proposed an analytical model to simulate the electromagnetic (EM) and induced polarization (IP) response of a metal well casing (Wait, 1983). To facilitate the analysis, the earth was idealized as a homogeneous conducting half‐space of electrical properties (σ, ε, μ). The well casing was represented as a filamental vertical conductor of semiinfinite length that was characterized by a series axial impedance to account for eddy currents and interfacial polarization. A further basic simplification was to neglect displacement currents in the air; this was justified when all significant distances were small compared with the free‐space wavelength. Initially, the source was taken to be a horizontal electric dipole or current element I ds on the air‐earth interface. By integration of the results, the mutual impedance between two grounded circuits could be ascertained. In the absence of the vertical conductor (i.e., the well casing) the results reduced to those given by Sunde (1968) and Ward (1967).

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Electromagnetic induction by a finite electric dipole source over a 2-D earth

Geophysics ◽

10.1190/1.1443406 ◽

1993 ◽

Vol 58 (2) ◽

pp. 198-214 ◽

Cited By ~ 75

Author(s):

Martyn J. Unsworth ◽

Bryan J. Travis ◽

Alan D. Chave

Keyword(s):

Finite Element ◽

Electromagnetic Fields ◽

Electric Dipole ◽

Numerical Solutions ◽

Current Source ◽

Three Dimensional ◽

Iterative Solution ◽

Electromagnetic Response ◽

Dipole Source ◽

Horizontal Electric Dipole

A numerical solution for the frequency domain electromagnetic response of a two‐dimensional (2-D) conductivity structure to excitation by a three‐dimensional (3-D) current source has been developed. The fields are Fourier transformed in the invariant conductivity direction and then expressed in a variational form. At each of a set of discrete spatial wavenumbers a finite‐element method is used to obtain a solution for the secondary electromagnetic fields. The finite element uses exponential elements to efficiently model the fields in the far‐field. In combination with an iterative solution for the along‐strike electromagnetic fields, this produces a considerable reduction in computation costs. The numerical solutions for a horizontal electric dipole are computed and shown to agree with closed form expressions and to converge with respect to the parameterization. Finally some simple examples of the electromagnetic fields produced by horizontal electric dipole sources at both the seafloor and air‐earth interface are presented to illustrate the usefulness of the code.

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Electromagnetic Fields Generated Above a Shallow Sea by a Submerged Horizontal Electric Dipole

IEEE Transactions on Antennas and Propagation ◽

10.1109/tap.2017.2681320 ◽

2017 ◽

Vol 65 (5) ◽

pp. 2707-2712 ◽

Cited By ~ 2

Author(s):

Jinhong Wang ◽

Bin Li

Keyword(s):

Electromagnetic Fields ◽

Electric Dipole ◽

Shallow Sea ◽

Horizontal Electric Dipole

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Scattering of a Plane Wave by an Anisotropic Plasma-Coated Conducting Sphere

International Journal of Antennas and Propagation ◽

10.1155/2011/409764 ◽

2011 ◽

Vol 2011 ◽

pp. 1-6 ◽

Cited By ~ 7

Author(s):

You-Lin Geng

Keyword(s):

Plane Wave ◽

Electromagnetic Fields ◽

Anisotropic Medium ◽

Free Space ◽

Numerical Results ◽

Wave Functions ◽

Vector Wave ◽

Homogeneous Plasma ◽

Conducting Sphere ◽

Spherical Vector

The electromagnetic field in homogeneous plasma anisotropic medium can be expressed as the addition of the first and second spherical vector wave functions in plasma anisotropic medium. The tangential electromagnetic fields are continued in the boundary between the homogeneous plasma anisotropic medium and free space, and the tangential electrical field is zero in the surface of conducting sphere. The coefficients of electromagnetic fields in plasma anisotropic medium expanded in terms of spherical vector wave functions in plasma anisotropic medium are derived, and then the coefficients of scattering fields in terms of spherical vector functions in free space can be obtained. Numerical results between this paper and hybrid finite element-boundary integral-multilevel fast multipole algorithm (FE-BI-MLFMA) are given, and they are in agreement very well. Some new numerical results of a plane wave scattering by an anisotropic plasma-coated conducting sphere are obtained.

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Effect of a Conducting Overburden on the Fields of a Buried Dipole Source

Canadian Journal of Physics ◽

10.1139/p75-076 ◽

1975 ◽

Vol 53 (6) ◽

pp. 598-609 ◽

Cited By ~ 3

Author(s):

V. Ramaswamy ◽

H. W. Dosso

Keyword(s):

Magnetic Fields ◽

Electromagnetic Fields ◽

Analytical Solutions ◽

Electric Dipole ◽

Lower Layer ◽

Low Frequency ◽

Dipole Source ◽

Vertical Electric Dipole ◽

Electric And Magnetic Fields ◽

Horizontal Electric Dipole

Analytical solutions for the low frequency electromagnetic fields of a dipole source situated in the lower layer of a two layer conductor are derived. The sources considered are a vertical electric dipole, a horizontal electric dipole, and a horizontal magnetic dipole. The numerical results discussed in this paper describe the general behavior of the electric and magnetic fields for various upper layer conductivities, upper layer thickness, and source depths. The results are of interest in the application of electromagnetic techniques to locate miners trapped underground following a mine disaster.

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