Harry Jones (University of Oxford, Clarendon Laboratory)
Title:Some Hands-on Experience of High Temperature Superconducting Magnets over 25 years
Abstract: Part of the excitement caused by the discovery of High Temperature Superconductors (HTS) was the prospect of very high field superconducting magnets. The feature of HTS that stimulated popular perception was its high critical temperature Tc: ~ 100 K. Coupled to that was the high upper critical field Bc2 ~ 100 T. By working at lower temperatures, this field range should have been accessible. However, the materials proved to be disappointingly intractable from the point of view of getting the critical current, Ic, good enough. Consequently, HTS magnet technology, so far, has not lived up to its early promise. In this paper, using illustrations of 4 systems, the author describes his own experience of HTS magnets and their difficulties / limitations but, with reference to the “second generation” HTS, namely coated conductors, the prospects of an improvement are reviewed. A Brief discussion of high fields for accelerators, e.g., ISIS, using non-superconducting, pulsed techniques is also presented.