Surface impedance of saturating iron in nonuniform pulsating fields

The use of well known one-dimensional surface impedance expressions in two- and three- dimensional field computation is inadequate where field strengths are varying rapidly, and near corners. The paper uses the wavefront method to derive expressions for the surface impedance of saturating iron when there are first- and second- order spatial variations of field at the surface. The results show that, in practical situations, first- order variations have a negligible effect, whereas the effect of second-order variations is more significant. It is shown that conditions around a 90¿¿ corner are simply obtained using the wavefront method.