Characterization of Deformed Magnets From External Magnetic Measurements

Due to the unavoidable construction tolerances and imperfections in the assembly of coils, the actual magnetic field of manufactured magnets differs from the design one. Depending on the consistency and the profile of the field error, a number of problems may arise, especially in high-performance devices, such as magnets for nuclear magnetic resonance or thermonuclear fusion devices. Typical quality insurance procedures can hardly reveal possible winding pack (WP) deformations. In this paper, deformed magnets are characterized by means of a limited set of parameters, providing an equivalent magnetic behavior, and an assessment of limits and possibilities of such a WP characterization from external magnetic field measurement is discussed, including some aspects of the inverse problem resolution.