临界电流密度对场冷超导磁悬浮力的影响研究

Influence of critical current density on levitation force of high-Tc superconducting system under field cooling condition

基于Kim临界态模型,通过考虑超导块材内部屏蔽电流的穿透历史过程,讨论了场冷条件下临界电流密度对高温超导悬浮系统磁悬浮排斥力和吸引力的影响。结果显示:最大超导磁悬浮排斥力和吸引力均随临界电流密度的增加呈指数关系增加,并趋于饱和;场冷条件下的磁悬浮力回滞能量损耗远高于零场冷情况;存在一个磁悬浮力比率κ,κ值对于评价大电流超导磁悬浮系统的机械性能具有重要作用。磁悬浮力随临界电流密度的这些变化特征可以用超导块材内部屏蔽电流的穿透情况进行合理地解释,为高温超导悬浮系统的工业应用提供了重要的理论依据。

After the penetration depth of superconducting currents and the internal magnetic field interior of the HTS were calculated,the influence of critical current density（Jc） on the interaction forces between a high-Tc superconductor（HTS） and a permanent magnet（PM） was investigated under field cooling process based on Kim critical state model.It was found that the maximum levitation forces including the attractive force and the repulsive force increased as an exponential function with the increasing of the Jc.They became to saturate at high Jc.The hysteresis energy loss of vertical force-displacement curve under field cooling condition was larger than the one under zero-field cooling condition.There was a force ratio κ,which was important on estimating the mechanics capability of superconducting levitation system with large Jc.All these relations could be explained with the penetration history of superconducting currents under field cooling condition.