Method of calculating low-frequency electromagnetic problems in cylindrical geometry

A numerical method of calculating harmonic electromagnetic field in the metallic pipe with rotational symmetry is proposed. The problem can have source located sufficiently far from the domain of interest, as well as multiple positions of the source along the axis. The method is based on the direct solution of discrete equations approximating differential problem by second order finite-differences. Exact non-local difference boundary conditions are used on faces, which are inhomogeneous if the source is outside the domain of interest.