Influence of Work Height on Guidance Force Decay of HTS Bulk Exposed to AC Magnetic Field Perturbation in a Maglev Vehicle System

Bulk superconductors have great potential for various engineering applications, especially in superconducting maglev vehicle systems using high-temperature superconducting bulks. In such a system, the HTS bulks were always exposed to AC external magnetic field, which was generated by the inhomogeneous surface magnetic field of the NdFeB guideway. In our previous work, it was observed that the guidance force of the YBCO bulk over the NdFdB guideway used in the high-temperature superconducting maglev vehicle system was decayed by the application of the AC external magnetic field. In this paper, we investigate the influence of the work height on the guidance force decay of HTS bulk exposed to an AC field perturbation in the maglev vehicle system and try to adopt a method to suppress the decay. From the experimental results, it was found that the decay rate of the guidance force was smaller at higher work height in the case of the same field-cooled height. So we could suppress the guidance force decay of HTS bulk exposed to AC external magnetic field perturbation in the maglev vehicle system by increasing the work height of the bulk.