悬浮在特定磁场中超导球的稳定性分析

Analysis on the Stability of the Superconducting Sphere Levitated in a Special Magnetic Field

主要分析了经过超导铌环整形后的螺管磁场的分布特点以及悬浮在其中的超导铌球受到扰动时的振动情况。用有限元方法计算出铌球在腔内不同位置时球外的磁场,结果表明整形铌环能够有效地改变磁场分布。通过分析铌球在振动过程中的表面磁场、悬浮力和振动速度的变化规律得出了铌球所允许的最大振动速度。根据铌球表面的磁场计算出球内的电磁场分布并根据二流体模型求出涡流损耗,分析了超导铌球在该磁场中悬浮的稳定性。

In this paper we mainly study the characteristics of the solenoidal magnetic field which is shaped by two niobium rings and the levitation of the niobium sphere when it is disturbed. We calculate the magnetic flux density out of the sphere with FEM method. The results show the niobium rings can effectively change the distribution of the magnetic field. Through analyzing the distribution of the magnetic field, the change of the levitation force and the vibration velocity of Nb sphere, we obtain the maximum vibration velocity that can be tolerated. After that the electromagnetic field in the sphere is calculated according to the field on the surface, and the eddy current loss is obtained according to the two-fluid model. At last we analyze the levitation stability of the system.