Prospects for the use of HTS in high field magnets for future accelerator facilities

The enthusiasm that followed the discovery of High Temperature Superconductors (HTS) and the hope that they could replace Low Temperature Superconductors (LTS) was damped by low current-carrying capacity, short piece lengths, and fragility of the brittle oxide materials. Development of applications was mainly on devices less demanding of conductor performance. However, with continuing development, progress was made with the cuprate superconductors, and long lengths of BSCCO 2223 and REBCO tape conductors are now commercially available. Progress has also been made in the development of BSSCO 2212 round wire, where implementation of a new production process has led to a breakthrough in performance. Though still at the research level, attainments in material synthesis and theoretical understanding of ironbased materials may lead to their development into practical superconductors, featuring high upper critical field and low anisotropy. A review of the potential of HTS as applied to accelerators is presented, with a focus on using the presently available materials and on the perceived needs for further development.