Permanent-magnet longitudinal fields for magnetostrictive devices

This paper discusses a technique for improving the homogeneity of the magnetic field of tube-like permanent magnets designed for magnetostrictive devices. The high homogeneity of the magnetic field along the tube is achieved by gradually changing shape or remanence of combined short rings. The analysis of the field in the magnet is performed using the magnetic charge principle and axial magnetic field equations are deduced. An example of design of a longitudinal uniform field for a magnetostrictive rod with large length to diameter ratio is presented.