Multi-Pole Components of Magnetic Field in Dipole Magnets Wound With High $T_{\rm c}$ Superconductor Tape and Feasibility of Their Accelerator Applications

Applications of high 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 superconductors are with flat tape shape. We studied the field quality of dipole magnets wound with high 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 superconductor tapes on field quality was discussed based on the numerical electromagnetic field analysis of superconductors.