Kim Model of Transport ac Loss with Position Dependent Critical Current Density in a Superconducting Cylinder

In this article, the dependence of the transport ac loss on field and position is investigated for a hard superconducting cylinder, which is consisted of two concentric shells with different critical current density. The Kim model is considered for the critical state in which the critical current density is assumed to depend on the flux density. Based on Norris’ equations, the analytic expression of the loss with field and position dependence is derived for the cylindrical specimen having a composite geometry. The results obtained show that the field and position dependent critical current density have obvious effects on the loss, which may explain why Norris’ predictions and the theoretical results have small differences.