Development and Fabrication of Superconducting Helical Coils for LHD

Development of Superconductors for the Helical Coils of LHD

Abstract

Composite-type superconductors with NbTi/Cu compacted strands and aluminum/copper stabilizers have been developed for use in the pool-cooled helical coils of the Large Helical Device (LHD). Topics related to the development, fabrication, short sample tests and soldered lap joint of these superconductors are summarized. Evaluation of AC loss has been made based on two measurement techniques. Heat transfer coefficients from the conductor surface to liquid helium have also been measured for the purpose of stability analysis.