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

Volume

20

Issue

3

fYear

2010

fDate

6/1/2010 12:00:00 AM

Firstpage

517

Lastpage

520

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;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/TASC.2009.2039781

Filename

5424110