The article carries out numerical analysis of the integral-equation method for the magnetotelluric sounding problem in a nonhomogeneous medium. The case of high-contrast conducting media is considered in detail, with a conducting nonhomogeneity embedded in a poorly conducting medium. Numerical analysis of the integral equation in this case shows that the solution has low accuracy if a traditional uniform rectangular grid is superposed on the nonhomogeneity and the electric field is evaluated at nodes traditionally placed at the centers of the grid cells. In this approach, nothing is done to resolve the field behavior at the nonhomogeneity boundary in the belied that the boundary conditions will be satisfied on their own automatically. Even the introduction of enhanced background conductivity does not improve the accuracy. A much better result is obtained when enhanced background conductivity is combined with a special nonuniform grid in which the cells in the top grid row have reduced height and the nodes are placed at the top boundary of these cells. This result is substantiated by allowing for the singularity of the integral equation.
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Translated from Prikladnaya Matematika i Informatika, No. 67, 2021, pp. 50–65.
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Barashkov, I.S. A Special Grid for the Numerical Analysis of the Integral Equation Method in the Magnetotelluric Sounding Problem. Comput Math Model 32, 305–318 (2021). https://doi.org/10.1007/s10598-021-09533-y
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DOI: https://doi.org/10.1007/s10598-021-09533-y