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

A hybrid boundary element method (BEM)-integral equation method (IEM) computation is proposed for the two-dimensional (2D) design of permanent MRI magnets. Over the finite element method (FEM), the hybrid BEM-IEM computation has the advantages of much less discrete elements and thus less computer memory and CPU time. As the curved shape of the ferromagnetic pole planes of permanent MRI magnets plays an important role in improving the uniformity of the magnetic field, a computer program using the hybrid computation is developed to optimize the pole plane shape visually and automatically. With a 0.2T Nd-Fe-B magnet, the proposed design method is carried out and the results are given in this paper.