Analyses of a solenoid magnet made of pancakes of coated conductors

Abstract

We estimated the distribution of currents and fields in a magnet which consisted of three coaxial solenoids; the solenoids were made by stacking pancakes of coated conductors (M). We used a model for the critical current densities which satisfied simple relations with magnitudes and directions of fields. Since various types of pinning centres result in different anisotropies in the field dependence of critical currents, their contributions to the properties of magnet were different. We found that the intrinsic pinning centres in CCs resulted in inefficient performance of the magnet as they were effective only in the pancakes in the central part of the magnet, where the fields were parallel to the ab-planes of the superconducting layers in the CCs. We estimated how much the magnet performances were improved by additions of columnar pinning centres or by addition of random point pinning centres.