Plasma and Fusion Research

Volume 13, 3402097 (2018)

Regular Articles

Surface Current Approximation of Magnetization Currents of Magnetic Materials in Axisymmetric Tokamak Devices for the Correction of their Effects on Magnetic Diagnostics
Takayuki KOBAYASHI, Hiroaki TSUTSUI1), Shinzaburo MATSUDA1) and Shunji TSUJI-IIO1)
School of Environment and Society, Tokyo Institute of Technology, Tokyo 152-8550, Japan
1)
Laboratory for Advanced Nuclear Energy, Institute of Innovative Research, Tokyo Institute of Technology, Tokyo 152-8550, Japan
(Received 28 December 2017 / Accepted 26 June 2018 / Published 10 August 2018)

Abstract

Magnetic materials such as ferritic steel are planned to be installed in fusion DEMO reactors to support blankets and in-vessel components with low activation. Since a magnetic material disturbs magnetic measurement, it is difficult to perform equilibrium control when plasma and sensors are placed between magnetic materials. To calculate the position of plasma current centroid with the disturbed magnetic measurement, we devised a simple scheme to correct their effects on magnetic diagnostics by approximating the magnetization currents as surface currents. Estimated errors of the position by this scheme, especially in the R position, are about 1%. Those with positionally dependent surface currents become smaller by relocating the filament positions for plasma current. Additionally, flux surfaces reconstructed by this correction show agreement with the true flux surfaces calculated by finite element method.

Keywords

ferritic steel, magnetic material, filament current approximation, surface current approximation, tokamak, DEMO

DOI: 10.1585/pfr.13.3402097

Full Text

PDF format (1.1Mbytes) PDF Download

References

  • [1] K. Takeuchi, M. Abe and H. Fukumoto, Jpn. J. Appl. Phys. 30, 398 (1991).
  • [2] C.V. Atanasiu and L.E. Zakharov, Comput. Phys. Commun. 70, 483 (1992).
  • [3] M. Tamura et al., J. Nucl. Mater. 155-157, 620 (1988).
  • [4] K. Tobita et al., Fusion Eng. Des. 81, 1151 (2006).
  • [5] K. Shinohara et al., Nucl. Fusion 47, 997 (2007).
  • [6] K. Urata, JAERI-Data/Code 2003-005 (2003) [in Japanese].
  • [7] D.W. Swain and G.H. Neilson, Nucl. Fusion 22, 1015 (1982).
  • [8] K. Kurihara, Fusion Eng. Des. 51-52, 1049 (2000).