Measurement of AC current distributions of a Bi-2223solenoidal coil by a pickup coil method

摘要

In order to investigate AC current distributions of high Tcsuperconducting coils, we developed a measurement method to evaluate thecurrent distributions of a solenoidal coil shape. In this method, wemeasured the field distributions by using pickup coils located around thecoil surface. To confirm the accuracy and sensitivity of this method, currentdistributions of a test coil made of a copper conductor were measured.Numerical and measured field distributions were compared, and it wasfound that our method was good enough to measure the currentdistributions for the high Tc superconducting coils. Using this method, wemeasured the current distributions of a Bi-2223 solenoidal coil in liquidnitrogen. This coil was wound a solenoid shape. Observed currentdistributions of this coil were compared with the characteristics of thecurrent distributions in the Bi-2223 tape exposed to an external magneticfield. On the basis of the obtained results the practicality of ourmeasurement method is discussed.