Analytical investigation of eddy currents in nonlinear ferromagnetic media for weak magnetic fields

Electromagnetic field diffusion into a nonlinear ferromagnetic conducting half-space is analytically investigated for weak magnetic fields. For these fields a "nth power" approximation for magnetization curves is used. The exact analytical solutions to the non-linear partial differential equations of electromagnetic field theory are found for circular polarization of incident waves. The case of noncircular polarization is treated as a perturbation of circular polarization. Linear equations for perturbations are then derived and their analytical solutions are found. The analytical theory is illustrated by the computational results for surface impedances and third harmonics of electromagnetic fields.