Calculation of the Magnetic Flux Leakage by a Spheroidal Inclusion in a Ferromagnetic Half‐Space

ABSTRACT A semi‐analytical calculation of the magnetic flux leakage owing to the presence of a spheroidal void inclusion in a ferromagnetic half‐space is presented. A decomposition strategy to a number of sub‐solutions that are associated with the different interfaces of the geometry, proposed in previous works, has been adopted. The fact that each sub‐solution is expressed in a conformal to the interface coordinate system results in a partially sparse linear system of equations, which are produced by mode‐matching at the interfaces, thus providing a very fast computation of the modal expansion coefficients and making the resulting scheme suitable for use with parametric inversion algorithms. The results of the method are compared against numerical simulations, carried out using a commercial finite elements package.