Drift of Levitated/Suspended Body in High- $T_{c}$ Superconducting Levitation Systems Under Vibration—Part I: A Criterion Based on Magnetic Force-Gap Relation for Gap Varying With Time

Levitation drift in the high-T
_c
superconducting levitation systems is directly related to the safe operation of the systems. In these levitation systems, the gap between a superconductor and a permanent magnet may decrease, increase, or keep unvarying with time. Based on the numerical simulations of the magnetic force-gap hysteresis relations of two different physical processes in field cooling, and the dynamic features at some given positions on major magnetic force-gap loops, a criterion described by the slopes of the given position on minor and major loops is proposed in this study. According to the suggested criterion, the drift phenomenon can be characterized by judging gap varying with time for a given levitation system. In addition, the characteristic of continuous space range of the equilibrium position of levitated/suspended body has been further exhibited from the numerical results.