Permanent Magnet and shim design

摘要

A general method for the design of structures composed of permanent magnetic material for producing and modifying magnetic fields. The method employs a finite set of permissible spatial harmonic modes upon a surface. In particular, it has applications where the structures are finite and open, for which an exact solution is not possible. The method determines an optimum distribution based upon a least squares minimization of the difference between the achievable and desired field within a Region Of Interest (ROI). The method also has application in passively improving the homogeneity of existing magnetic fields (shimming) by distributing magnetic materials in the vicinity of the ROI.