Bulk Superconductor Levitation Devices: Advances in and Prospects for Development

Maglev train is a transportation system that uses magnetic interaction and brings many technical, economic, and environmental benefits. Here, the progress in designing and manufacturing portable vacuum cryostats containing 24 high-quality threefold seeded Yttrium Barium Copper Oxide (YBCO) bulks with up to 40 h LN2 cooled operation time is reported. Permanent magnet (PM) excitation on a magnetic guideway generates forces on the YBCO cryostats and provide train levitation forces of several tons by assembling the portable cryostats. By means of experiments and systematic improved fabrication, we describe the process of material and device scaling-up to gain industrial-near transformation and application. Current PM guideway design with the magnetic flux of 0.5 T at maximum limits the force density to 5-10 N/cm
²
. The conditions for further development, effective fabrication, and design-oriented progress of higher loads, great robustness, and better thermal insulation respective longer operation time are outlined.