Three-dimensional em modeling

Three-dimensional (3D) interpretation of electromagnetic (EM) dsta is still in its infancy, due to a lack of practical numerical solutions for the forward problem. However, a number of algorithms for simulating the responses of simple 3D models have been developed over the last ten years, and they have provided important new insight. Integral equation methods have been more successful than differential equation methods, because they require calculating the electric field only in small anomalous regions, rather than throughout the earth. Utilizing a vector-scalar potential approach and incorporating symmetry through group theory improves the general 3D integral equation solution. Thin-sheet integral equation formulations have been particularly useful. Much recent research has focused on hybrid methods, which are finite element differential equation solutions within a mesh of limited extent, with boundary values determined by integrating over the interior fields. An elegant eigencurrent technique has been developed for calculating the transient response of a thin 3D sheet in free space, but general 3D time domain responses have only been calculated by Fourier transforming frequency domain results. Direct time domain calculations have been carried out only for 2D bodies.

[1]  D. Wilton,et al.  Analysis of various numerical techniques applied to thin-wire scatterers , 1975 .

[2]  Alexander Peter Annan.  The equivalent source method for electromagnetic scattering analysis and its geophysical application , 1974 .

[3]  F. W. Jones,et al.  A Discussion of the Finite Difference Method in Computer Modelling of Electrical Conductivity Structures. A Reply to the Discussion by Williamson, Hewlett and Tammemagi , 1974 .

[4]  G. W. Hohmann.  Three-Dimensional Induced Polarization and Electromagnetic Modeling , 1975 .

[5]  G. W. Hohmann,et al.  Integral equation modeling of three-dimensional magnetotelluric response , 1981 .

[6]  T. Madden,et al.  Generalized thin sheet analysis in magnetotellurics: an extension of Price's analysis , 1980 .

[7]  E. Miller,et al.  Some computational aspects of thin-wire modeling , 1975 .

[8]  Gordon F. West,et al.  The Electromagnetic Response of a Conductive Inhomogeneity in a Layered Earth , 1976 .

[9]  C. R. Brewitt-Taylor,et al.  On the finite difference solution of two-dimensional induction problems , 1976 .

[10]  Roger F. Harrington,et al.  Field computation by moment methods , 1968 .

[11]  S. Frankel,et al.  Stability conditions in the numerical treatment of parabolic differential equations , 1953 .

[12]  John T. Kuo,et al.  Transient time-domain electromagnetics , 1980 .

[13]  G. W. Hohmann,et al.  An investigation of finite-element modeling for electrical and electromagnetic data in three dimensions , 1981 .

[14]  F. W. Jones,et al.  The calculation of magnetotelluric quantities for three‐dimensional conductivity inhomogeneities , 1978 .

[15]  D. Rankin,et al.  Three-dimensional modelling in magnetotelluric and magnetic variational sounding , 1977 .

[16]  J. T. Weaver,et al.  Three-dimensional induction in a non-uniform thin sheet at the surface of a uniformly conducting earth , 1979 .

[17]  Art Raiche,et al.  Lecture notes from the US?Australia electromagnetic workshop , 1978 .

[18]  Ki Ha Lee,et al.  A hybrid three-dimensional electromagnetic modeling scheme , 1981 .

[19]  Alan C. Tripp,et al.  Block Diagonalization of the Electromagnetic Impedance Matrix of a Symmetric Buried Body Using Group Theory , 1984, IEEE Transactions on Geoscience and Remote Sensing.

[20]  A. Raiche.  An Integral Equation Approach to Three-Dimensional Modelling , 1974 .

[21]  U. Das,et al.  Electromagnetic response of an arbitrarily shaped three-dimensional conductor in a layered earth — numerical results , 1982 .

[22]  T. Lee.  Transient electromagnetic response of a sphere in a layered medium , 1975 .

[23]  The construction of effective methods for electromagnetic modelling , 1982 .

[24]  G. Vasseur,et al.  Bimodal electromagnetic induction in non-uniform thin sheets with an application to the northern Pyrenean induction anomaly , 1977 .

[25]  Gerald W. Hohmann,et al.  Electromagnetic modeling of three-dimensional bodies in layered earths using integral equations , 1983 .

[26]  F. W. Jones,et al.  The Perturbation of Alternating Geomagnetic Fields by Three‐dimensional Island Structures , 1973 .