Two-domain analysis of field-producing bodies, using fictitious poles

An unconventional numerical method is presented for analysing the behaviour of a field-producing body, e.g. a bar magnet. The body shape is restricted to axisymmetry and to mirror-image symmetry about a central plane, but is otherwise general. The body internal features are likewise general, and may include mixed materials having non-linear properties. The basic principle is always to have a specified surface potential distribution upon trial. It is shown that the external and internal analyses may then proceed independently. Externally, Laplace's equation is solved using a sparse set of fictitious internal poles. The solution is self-validating, and provides a direct transformation from surface potential to internal body flux distribution taking account of any applied external field. Internally, flux is then converted using simple circuit technique to a new surface potential distribution.