Feasibility of a Short-Period Superconducting Undulator Using 2G HTS Tapes

This paper presents a design concept of a planar-type superconducting undulator (SCU) using YBCO high-temperature superconductor (HTS) tapes. The SCU has a period length of 15 mm, and the tape conductor has dimensions of 4-mm width and 0.1-mm thickness. It has been shown that the conductor transition from one coil groove to the one in the next period is possible by making a semi-circular concave loop of the tape for continuous winding in the same direction. Non-uniform current distribution in the tape may cause field quality degradation. Assuming a uniform current density in the tape, the engineering critical-current density of the HTS in the coil for the design and the corresponding achievable on-axis peak field at 4.2 K were calculated.