Hybrid FEM-BIM formulation using electric and magnetic variables

A hybrid finite-element-boundary-integral method using a mixed electric-magnetic formulation for 3-D eddy current computation is presented. The finite element formulation using tetrahedral edge elements in terms of electric field is employed in the conducting region. The boundary integral method in terms of magnetic field is used in the air space. The use of a vector variable in the air space together with a boundary spanning tree technique makes it possible to solve multiply connected problems and leads to a diminution of boundary unknowns. The electric and the magnetic variables are coupled on the boundary of the domain through the boundary continuity of electric and magnetic fields; the coupling matrices thus obtained are the transposes of one another. Results concerning this mixed coupling method and comparison with the other hybrid methods are reported