A canonical solution to the three‐dimensional electromagnetic prospecting problem

The problem of three‐dimensional scattering from anomalies buried in the earth is considered. In the general situation, this requires the fields to be evaluated using two‐dimensional numerical integration. In this or the related inverse problem, subsurface characteristics are extracted from a two‐dimensional grid of surface field measurements. This grid of points is computed with time‐saving two‐dimensional digital Fourier transforms, i.e., with plane‐wave analysis. A simple method for selection of sampling windows and increments in x and κ (wavenumber) space which bounds and minimizes aliasing errors is presented and used. The theory is applied to the canonical problem of magnetic dipole excitation of a buried cylinder.