Electromagnetic fields of electric dipoles embedded in a stratified anisotropic earth

Xiong, Zonghou

doi:10.1190/1.1442633

Cited by 43 publications

(22 citation statements)

References 4 publications

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“…In order to compute the EC a of a layered ground, based on measurements made using a horizontal or vertical magnetic dipole configuration, we used the well-known electromagnetic analytical solution for cylindrical model symmetry (given by Wannamaker et al 1984;Ward and Hohmann, 1988;Xiong, 1989). However, in the case of thin layers or high-frequency content, convergence problems can be encountered in the numerical integration of the corresponding oscillating Bessel functions.…”

Section: Emi Surveys and Calibrationmentioning

confidence: 99%

Multiconfiguration electromagnetic induction survey for paleochannel internal structure imaging: a case study in the alluvial plain of the River Seine, France

Réjiba

Schamper

Chevalier

et al. 2018

Hydrol. Earth Syst. Sci.

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Abstract. The La Bassée floodplain area is a large groundwater reservoir controlling most of the water exchanged between local aquifers and hydrographic networks within the Seine River basin (France). Preferential flows depend essentially on the heterogeneity of alluvial plain infilling, whose characteristics are strongly influenced by the presence of mud plugs (paleomeander clayey infilling). These mud plugs strongly contrast with the coarse sand material that composes most of the alluvial plain, and can create permeability barriers to groundwater flows. A detailed knowledge of the global and internal geometry of such paleomeanders can thus lead to a comprehensive understanding of the long-term hydrogeological processes of the alluvial plain. A geophysical survey based on the use of electromagnetic induction was performed on a wide paleomeander, situated close to the city of Nogentsur-Seine in France. In the present study we assess the advantages of combining several spatial offsets, together with both vertical and horizontal dipole orientations (six apparent conductivities), thereby mapping not only the spatial distribution of the paleomeander derived from lidar data but also its vertical extent and internal variability.

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Section: Emi Surveys and Calibrationmentioning

confidence: 99%

Multiconfiguration electromagnetic induction survey for paleochannel internal structure imaging: a case study in the alluvial plain of the River Seine, France

Réjiba

Schamper

Chevalier

et al. 2018

Hydrol. Earth Syst. Sci.

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“…Kwon and Wang (1986) solve the VTI-layeredearth problem by splitting transverse electric (TE) and transverse magnetic (TM) modes. Xiong (1989) uses vector potentials to solve for the electromagnetic fields in a stratified anisotropic medium. Michalski (2005) derives the Green's tensor in layered VTI media using the transmission-line analogue.…”

Section: Introductionmentioning

confidence: 99%

The electromagnetic response in a layered vertical transverse isotropic medium: A new look at an old problem

2015

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We determined that the electromagnetic vertical transverse isotropic response in a layered earth can be obtained by solving two equivalent scalar equations, which were for the vertical electric field and for the vertical magnetic field, involving only a scalar global reflection coefficient. Besides the complete derivation of the full electromagnetic response, we also developed the corresponding computer code called EMmod, which models the full electromagnetic fields including internal multiples in the frequency-wavenumber domain and obtains the frequency-space domain solutions through a Hankel transformation by computing the Hankel integral using a 61-point Gauss-Kronrod integration routine. The code is able to model the 3D electromagnetic field in a 1D earth for diffusive methods such as controlled source electromagnetics as well as for wave methods such as ground penetrating radar. The user has complete freedom to place the source and the receivers in any layer. The modeling is illustrated with three examples, which aim to present the different capabilities of EMmod, while assessing its correctness.

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“…The interaction of a spatially non-uniform electromagnetic field with an anisotropic medium has been studied in various contexts by many authors for particular source configurations, mainly for dipole source fields in layered conductors (e.g., Chlamtac and Abramovici, 1981;Xiong, 1989;Li and Pedersen, 1992;Everett and Constable, 1999). In these studies, the particular symmetry of the source field is exploited explicitly, and closed-form solutions are obtained for the electromagnetic field.…”

Section: Introductionmentioning

confidence: 99%

Generalized Riccati equations for 1-D magnetotelluric impedances over anisotropic conductors Part II: Non-uniform source field model

Kováčiková

Pek

2014

Earth Planet Sp

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The Riccati equation approach to the analysis of magnetotelluric impedances in 1-D anisotropic structures is generalized to models with non-uniform source field excitation. The problem is solved in the horizontal wavenumber domain. General Riccati matrix equations for the spectral impedances of the medium are derived and their relation to the standard impedance propagation formulae in layered anisotropic models is discussed. Riccati equations give a full solution for the spectral impedances, comprising both the induction and galvanic mode. For a purely inductive excitation of the field, each wave-number harmonics of the magnetic field is strictly linearly polarized on the surface, and only one half of the spectral impedance tensor can be restored. Both induction and galvanic modes generally exist inside the anisotropic conductor and are coupled. A formal similarity between the Riccati equations for a 1-D anisotropic medium with non-uniform sources and those obtained for 2-D laterally inhomogeneous structures is demonstrated, which indicates a possible way of extending the Riccati impedance/admittance equations to multi-dimensional conductors.

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Electromagnetic fields of electric dipoles embedded in a stratified anisotropic earth

Cited by 43 publications

References 4 publications

Multiconfiguration electromagnetic induction survey for paleochannel internal structure imaging: a case study in the alluvial plain of the River Seine, France

Multiconfiguration electromagnetic induction survey for paleochannel internal structure imaging: a case study in the alluvial plain of the River Seine, France

The electromagnetic response in a layered vertical transverse isotropic medium: A new look at an old problem

Generalized Riccati equations for 1-D magnetotelluric impedances over anisotropic conductors Part II: Non-uniform source field model

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