Design of an axisymmetric permanent magnet structure for magnetic resonance tomography

New Nd-Fe-B permanent magnet materials are considered to have interesting characteristics for the realization of tomographs for magnetic resonance imaging. To provide a comparison between these structures and superconducting or resistive magnets, the design of an axisymmetric permanent magnet for MRI has been carried out using a general-purpose code for electromagnetic-field computation that also allowed for the analysis of anisotropic media. The main computational difficulties due to the field uniformity requirements are analyzed. The obtained results are displayed and the design criteria used, as well as the optimizations performed, are described and discussed.