Magnetic gradient levitation using high-Tc bulk superconductors

The magnetic gradient levitation system using high-Tc bulk superconductors and iron rails has been studied by numerical analysis of their electromagnetic field. This system enables stable levitation, even at a standstill, without active control, by the nux pinning of the superconductors. Emphasis is put on the analysis of the dependence of the levitation characteristics on the critical current density in the superconductor. Numerical analysis results show that levitation characteristics are strongly dependent on the critical current density. Bulk superconductors with a critical current density higher than 2x10(8)A/m(2) are required for stable levitation and sufficient force can be generated in the case of the system model considered in this paper.