Title :
AC Losses in Poloidal Coils of the Large Helical Device
Author :
Takahata, Kazuya ; Chikaraishi, Hirotaka ; Mito, Toshiyuki ; Imagawa, Shinsaku
Author_Institution :
Nat. Inst. for Fusion Sci., Gifu, Japan
fDate :
6/1/2010 12:00:00 AM
Abstract :
AC losses in poloidal coils of the Large Helical Device (LHD) have been measured during single-pulse operations. The superconductors of the coils are Nb-Ti cable-in-conduit conductors (CICC) cooled by supercritical helium. The enthalpy increase due to the losses was observed at the inlet and outlet of the helium coolant. Time constants of the coupling losses can be estimated using analytical expressions with a circuit model and by considering the magnetic field distribution in the coil. The estimated time constants are 80 and 200 ms for two of the poloidal coils. We found a clear difference in the time constants, even though the two coils were fabricated with exactly the same design.
Keywords :
fusion reactor design; plasma toroidal confinement; stellarators; superconducting coils; superconducting materials; AC loss; Large Helical Device; Nb-Ti cable-in-conduit conductors; circuit model; coupling losses; fusion device; helium coolant; magnetic field distribution; poloidal coils; single-pulse operations; supercritical helium; time constants; AC loss; cable-in-conduit conductor; fusion device; superconducting coils;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
DOI :
10.1109/TASC.2009.2039781
