Computer aided magnetic field calculations for nonlinear shielding materials

A general computer program, developed to calculate magnetic fields in the presence of ferromagnetic shields, solves the two-dimensional Laplace equation on a rectangular grid of up to 5000 nodes using the difference-equation technique. It may assume the magnetic induction to be either a linear or nonlinear function of field strength . Shielding material thickness for most applications is small compared to the difference equation grid resolution. Therefore, a resistor network analogy was used to appropriately modify the difference equation for thin materials on a uniform grid.