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

A permanent-magnet type mixed-/spl mu/ levitation system, which only needs an iron, permanent magnets and bulk superconductors, can realize an advantageous levitation system-for example, for transportation over a relatively long distance because of its simple structure and stable levitation without active control. A three-dimensional numerical analysis of electromagnetic force characteristics in the mixed-/spl mu/ levitation system is carried out and the results of the analysis are compared with experiments. From these results, the authors have confirmed that the three-dimensional structure of the magnetic field and the electromagnetic performance of superconductors strongly influence the characteristics of the electromagnetic force acting on the iron, which become unstable in some cases.