DEVELOPMENT OF MATHEMATICAL TOOLS TO DETERMINE OPTIMUM ENCLOSURE DESIGNS FOR CONTROLLING ELECTROMAGNETIC-FIELDS

Electromagnetic fields are present wherever sources of currents are fo und. Conventional shielding against these electromagnetic fields is ac complished by using complete ferromagnetic enclosures. Maxwell's equat ions govern the phenomenon of electromagnetic fields in discontinuous media, and analytical solutions in the presence of enclosures of arbit rary shapes are not available. Hence, Maxwell's equations are solved n umerically using the finite element method in conjunction with the mag netic scalar potential approach. The test case for the verification of the numerical code is a long cylindrical ferromagnetic shell placed i n a transverse uniform magnetic field for which an analytical solution is derived here. The comparison of analytical and numerical solutions validates the accuracy of the numerical code. As expected the magneti c field inside the complete enclosure varies inversely to the relative permeability of the enclosure. Using this approach, enclosures of dif ferent shapes can be designed.