Levitation Force Transition of High-Tc Superconducting Bulks in Varying External Magnetic Field

In practical application of a High-Tc Superconducting (HTS) maglev vehicle, the onboard HTS bulks are inevitably exposed to a varying inhomogeneous field due to present processing and assembling technology of the permanent magnetic guideway (PMG). To explore the influence on the levitation forces of YBa₂Cu₃O_7-x bulk samples in such changing external magnetic field due to different traveling speeds, we experimentally investigated the general transition of said levitation force under such varying external field simulated by a spinning circular PMG. The force waves attenuated in accordance to the varying of the applied field dependent on the PMG´s rotating speed: attenuating when speeding up and rising slightly when speeding down. This observed phenomenon is of great importance in design and application of the HTS maglev system.