Testing Composite Superconductor for the LRL Baseball Magnet

30 Years of Conductors for Fusion: A Summary and Perspectives

“…Shorts in the windings (either intentional, for protection, or non-intentional, due to winding movement) were common [5]. Training, due to movement of the non-impregnated turns, was also frequent, mostly in the baseball type coils [6], [7], where helium vapor locked between the turns was also an issue.…”

“…Graded solenoids up to 10.3T were used in the SUMMA device at NASA (NbTi and , with up to 170 in high field) [5] and in the LIN-5 at Kurchatov, NbTi up to 5.8 T [6]. More sophisticated, very similar, "baseball" type coils were developed at Livermore, Baseball II-T [7], and at Kurchatov, LIN-5B [8], using NbTi multifilament composites with square cross section, see also Table I. Since the early applications, the design of a superconducting winding/conductor reflects the input of three drivers. First is the available material and technology, e.g.…”

“…THE EARLY LESSONS Stability and protection are the main fields where progress was made in the early applications of superconductors for fusion, all bath cooled [1]- [8]. After disappearing of the NbZr conductors, the key issue for the new multifilament NbTi composites was to identify the proper filament size to cure the flux jump induced quenches [7]. Flux jumps were also an issue for the wide tapes in the edge of the high field solenoid, where the field component perpendicular to the tape is large [4].…”