ELECTROMAGNETIC AND ELECTRICAL MODELING BY THE FINITE ELEMENT METHOD

Application of the finite element method to the solution of physical problems is based on minimization of energy; in the present case electromagnetic energy is minimized. Representation of a volume of space by a number of finite elements and description of field or potential distribution by a finite set of unknown values make it possible to replace the energy variational equation by matrix equations. It is shown that a solution for secondary rather than total field quantities can be obtained directly. Such a procedure has several advantages. Approximations are involved in using non‐infinitesimal elements and finite meshes of elements. It is usually necessary to pay more attention to mesh size than texture (element size). Examples of induced polarization anomalies over two‐dimensional models illustrate effects of topography and of a highly conducting layer above bodies of polarizable material. Computed electromagnetic anomalies of two‐dimensional structures, with line source excitation, include the effects of adjacent conductors and magnetic conductors set in a less conductive half‐space.