Three-dimensional structure of magnetic field in the mixed-mu levitation system using bulk superconductors

A permanent-magnet type mixed-mu levitation system, which only needs an iro n, permanent magnets and bulk superconductors, can realize an advantageous levitation system, for example, for transportation over a relatively long d istance because of its simple structure and stable levitation without activ e control. A three-dimensional numerical analysis of electromagnetic force characteristics in the mixed-mu levitation system is carried out and the re sults of the analysis are compared with the experimental. From these result s we have confirmed that the three-dimensional structure of magnetic field and the electromagnetic performance of superconductors strongly influence t he characteristics of the electromagnetic force acting on the iron, which b ecome unstable in some cases.