Influence of flux creep on dynamic behavior of magnetic levitation systems with a high-T/sub c/ superconductor

Significant flux creep may be generated in some high-T/sub c/ superconductors with weak pinning, which could yield an influence on the dynamic behavior of a high-T/sub c/ superconductor-magnet levitation system. To investigate this influence, this article presents a numerical analysis of dynamic features of the levitation generated by an interaction between a high-T/sub c/ superconductor (HTSC) and a permanent magnet (PM) after the flux creep in the superconductor is taken into account in a macro-model of superconductivity. The influence is comprehensively displayed by comparing the predictions of dynamic responses of such systems in which the flux creep in the superconductor is and is not taken into account. The obtained results show that whether or not the flux creep results in a noticeable influence to the levitation of superconductor-magnet systems is mainly dependent upon properties of superconductivity and applied excitation, e.g., critical current density of superconductors, and amplitude and frequency of external excitations. When the critical current density is less than 4.5/spl times/10/sup 8/ A/m/sup 2/, and the system is subjected to a periodic excitation, the influence of flux creep should be taken into account in the theoretical analysis.