[Table of Contents]

Plasma and Fusion Research

Volume 6, 2405077 (2011)

Regular Articles

Hysteresis Loss in Poloidal Coils of the Large Helical Device
Kazuya TAKAHATA, Hirotaka CHIKARAISHI, Toshiyuki MITO and Shinsaku IMAGAWA
National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan
(Received 22 December 2010 / Accepted 15 February 2011 / Published 12 July 2011)

Abstract

Hysteresis loss in poloidal coils of the Large Helical Device (LHD) has been measured during single-pulse operation. The superconductors of the coils are Nb-Ti cable-in-conduit conductors (CICC) cooled by forced-flow supercritical helium. The loss was measured by monitoring the enthalpy increase of the helium coolant between the inlet and outlet. Although the hysteresis loss was extracted by extrapolating several data sets from pulse excitations with different sweep rates, the extrapolated loss was much larger than the estimation using the magnetic hysteresis of the conductor. The anomalous increase in the loss is likely due to inter-strand coupling loss with long time constants from the order of 10 to 1000 s. The calculations show that the additional coupling loss behaves like a hysteresis loss.

Keywords

cable-in-conduit conductor, hysteresis loss, coupling loss, LHD, superconducting magnet

DOI: 10.1585/pfr.6.2405077

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References

  • [1] M. Fujiwara et al., J. Fusion Energy 15, 7 (1996).
  • [2] H. Chikaraishi et al., Proc. 13th European Conf. on Power Electronics and Applications, Barcelona, Spain, 2009, Article number 5279116.
  • [3] K. Takahata et al., Fusion Eng. Des. 65, 39 (2003).
  • [4] K. Takahata et al., IEEE Trans. Appl. Superconductivity 20, 517 (2010).
  • [5] Y. Takahashi et al., IEEE Trans. Appl. Superconductivity 11, 1546 (2001).
  • [6] S. Lee et al., IEEE Trans. Appl. Superconductivity 16, 771 (2006).
  • [7] K. Takahata et al., Fusion Eng. Des. 81, 2571 (2006).
  • [8] V. B. Zenkevitch and A. S. Romaniuk, IEEE Trans. Magn. MAG-13, 567 (1977).

This paper may be cited as follows:

Kazuya TAKAHATA, Hirotaka CHIKARAISHI, Toshiyuki MITO and Shinsaku IMAGAWA, Plasma Fusion Res. 6, 2405077 (2011).