A reformalism for computing frequency‐ and time‐domain EM responses of a buried, finite‐loop source in a layered earth

Da, Umesh C.

doi:10.1190/1.1887562

Cited by 2 publications

(6 citation statements)

References 6 publications

(6 reference statements)

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“…After Das (1995), for a horizontal wire-loop source, the tangential electric fi eld at the interface is continuous, whereas the orthogonal tangential magnetic field is discontinuous. The same holds for a horizontal electrical dipole.…”

Section: Boundary Conditionsmentioning

confidence: 99%

“…We derive the initial amplitudes for potentials by starting with equation (14) and following a similar procedure as Das (1995).…”

Section: Vmd and Hed Sourcementioning

confidence: 99%

“…Thus, equations (1) and (2) turn into scalar differential equations with complex exponential functions as solutions, representing the upward and downward traveling waves. In the spectrum domain, to ensure numerical stability, we adopt the idea of Das (1995) and write the solutions as A are the spectral counterparts of A z,l and F z,l of the space domain (two-dimensional Fourier transformation). A l + and A l -are the amplitudes of the downgoing and upgoing TM mode wave potentials, while F l + and F l -are the amplitudes for the TE mode.…”

Section: Potentials and Fi Eldsmentioning

confidence: 99%

“…The amplitudes of the spectral function in each layer can recur downward and upward from the initial amplitude at the source level by using the boundary reflection coefficients. The reflection coefficients can be defined from the accumulated conductance in the spectral domain as (Das, 1995) 2 ,TE 0 1 2 ,TE 1 , 1, ,…”

Section: Refl Ection Coeffi Cients Via Accumulated Conductancementioning

confidence: 99%

“…At fi rst glance, the discontinuity seems to complicate the computation of Green's function; however, this disadvantage will be compensated by making the spectrum-domain Helmholtz equation homogeneous, leading to uniform solutions for the EM partial waves. These merits still are in the work when trying to calculate Green's functions for a VMDlike source buried in a layered earth (Das 1995;Das and Hoop 1995), and later developed by Krivochieva and Chouteau (2002) to compute underground large loop TEM response.…”

Section: Introductionmentioning

confidence: 99%

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Singularity-free Green’s function for EM sources embedded in a stratified medium

et al. 2016

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We present a method to unify the calculation of Green's functions for an electromagnetic (EM) transmitting source embedded in a homogeneous stratifi ed medium. A virtual interface parallel to layer interfaces is introduced through the source location. The potentials for Green's function are derived by decomposing the partial wave solutions to Helmholtz's equations into upward and downward within boundaries. The amplitudes of the potentials in each stratum are obtained recursively from the initial amplitudes at the source level. The initial amplitudes are derived by coupling with the transmitting sources and following the discontinuity of the tangential electric and magnetic fi elds at the source interface. Only the initial terms are related to the transmitting sources and thus need to be modifi ed for different transmitters, whereas the kernel connected with the stratifi ed media stays unchanged. Hence, the present method can be easily applied to EM transmitting sources with little modification. The application of the proposed method to the marine controlled-source electromagnetic method (MCSEM) demonstrates its simplicity and fl exibility.

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Section: Boundary Conditionsmentioning

confidence: 99%

“…We derive the initial amplitudes for potentials by starting with equation (14) and following a similar procedure as Das (1995).…”

Section: Vmd and Hed Sourcementioning

confidence: 99%

Section: Potentials and Fi Eldsmentioning

confidence: 99%

Section: Refl Ection Coeffi Cients Via Accumulated Conductancementioning

confidence: 99%