Multi-Pole Components of Magnetic Field in Dipole Magnets Wound With High T-c Superconductor Tape and Feasibility of Their Accelerator Applications

Applications of high T-c superconductors to accelerator magnets are attractive from the viewpoint of cooling cost reduction and that of generating very high magnetic field at low temperature. However, in magnets using cosine-theta like coils, three-dimensional shape of coil ends and magnetic field quality might be concerns, because most of practical high T-c superconductors are with flat tape shape. We studied the field quality of dipole magnets wound with high T-c superconductor tapes. Case studies on magnetic field design were made for dipole magnets wound with coated conductors: we designed two magnets and calculated multi-pole components of the magnetic field to evaluate their field qualities. The torsion/bending tolerance of coated conductors was studied experimentally to clarify the feasibility of three-dimensional winding. The influence of the shielding current in high T-c superconductor tapes on field quality was discussed based on the numerical electromagnetic field analysis of superconductors