Experimental Hysteretic Loss for a Series of Superconducting Filamentary NbTi Wires and a Field Dependent Critical State Model.

摘要

This report summarizes the Air Force superconducting wire applications, the goals of future superconducting materials development, the state of the art theories of ac loss in superconductors, and the results of hysteretic loss measurements on a series of niobium titanium multifilamentary wires. Expressions were developed for magnetization and hysteretic loss for half cycle and full cycle for rod geometries for a critical state model with critical current inversely proportional to field. Bulk effects with surface like character are discussed along with surface shielding fields and the demagnetizing factor. The loss expressions of various models are compared to experimental loss. Universal loss curves constructed from experimental loss curves by appropriate normalization are obtained and used to predict loss accurately.