Optimization of systems of permanent magnets

Abstract

Various systems of permanent magnets with a large magnetic anisotropy, in which strong stray magnetic fields are generated, have been calculated. A classification of the magnet systems and corresponding strong fields into linear and point systems is suggested. It is shown that the greatest linear field can be obtained in a system of the Halbach-cylinder type, in which this field tends to Hx = 4πMsln(a/x) with increasing number of uniformly magnetized sectors. The limiting value of the point field is obtained in systems of a large number of conical magnets each separated into many sectors. Such a field approaches Hx ∼ 8πMsln(a/x) in magnitude.