Thermal Modeling of Canted Cosine Theta Dipole Magnets Wound Using Defected REBCO Cables

In this paper we analyzed numerically, using a Finite Element Method (FEM), the performance of REBCO CORC cable where we have assumed defects are present. In particular, we focus on the influence of the defects on heating and thermal runaway of the magnets. Defects, which are possible in any HTS cable, may originate from the tape manufacture, or during cabling, or in service. Here we considered a design based on real Canted Cosine Theta (CCT) dipole magnet, wound using CORC cable, which was built and tested at the Lawrence Berkeley National Laboratory, USA as a stand-alone dipole magnet providing a magnetic field of 1.2 T in liquid He bath at 4.2 K. Because, thermally at least, the turns of the CCT dipole magnet behave as parallel straight wires immersed half way in the grooves of the mandrel material with their outside surfaces in direct contact with pool boiling liquid He, in our FEM model we adopted a 3D straight geometry which significantly reduces the computational time and memory. To model the REBCO superconducting material we used its measured power law E-J curve.