2D visual design of permanent MRI magnets by a hybrid BEM-IEM computation

A hybrid Boundary Element Method (BEM)-Integral Equation Method (IEM) compu tation is proposed for the two-dimensional (2D) design of permanent MRI mag nets. Over the Finite Element Method (FEM), the hybrid BEM-IEM computation has advantages of much less discrete elements and thus less computer memory and CPU time. As the curved shape of the ferromagnetic pole planes of perm anent MRI magnets plays an important role in improving the uniformity of th e magnetic field, a computer program using the hybrid computation is develo ped to optimize the pole plane shape visually and automatically. With a 0.2 T Nd-Fe-B magnet the proposed design method is carried out and the results are given in this paper.