FINITE-DIFFERENCE CALCULATION OF DEMAGNETIZING FACTORS FOR SHAPES WITH CYLINDRICAL SYMMETRY

The effect of the demagnetizing field plays an important part in deter mining the response to applied magnetic fields of samples which form i ncomplete magnetic circuits. The demagnetizing factor N is usually cal culated using a surface magnetic charge model to deduce the demagnetiz ing held, In this work, a finite-difference method is used to calculat e the flux density for a given applied field. The effective permeabili ty mu(rod) is then deduced. N is calculated by comparing mu(rod) with mu(r), the intrinsic permeability of the material. Calculations for cy linders and ellipsoids give very good agreement with surface charge me thods. Advantages of this approach include ease of application to more complex shapes and the potential for application to non-linear materi als. (C) 1998 Elsevier Science B.V. All rights reserved.