[Table of Contents]

Plasma and Fusion Research

Volume 5, S2097 (2010)

Regular Articles

Three-Dimensional Analysis of Beamlet Deflection in a MeV Accelerator for ITER NBI
Mieko KASHIWAGI, Masaki TANIGUCHI, Naotaka UMEDA, Takatoshi MIZUNO, Hiroyuki TOBARI, Masayuki DAIRAKU, Kazuhiro WATANABE and Takashi INOUE
Japan Atomic Energy Agency (JAEA), 801-1 Mukoyama, Naka 311-0193, Japan
(Received 18 December 2009 / Accepted 4 March 2010 / Published 10 December 2010)

Abstract

At Japan Atomic Energy Agency (JAEA), a MeV accelerator has been developed to demonstrate acceleration of H− ion beams at the ITER-relevant power density. After long pulse beam acceleration tests of up to 10 s, molten areas were observed around the apertures of the grids due to excess heat load on the grids. To identify the cause of the melting, a three-dimensional (3D) beam analysis was performed. The stripping loss of negative ions and magnetic fields in the accelerator were included in the calculation to examine the beam trajectories precisely. It was clarified that the beamlet deflection angle was larger than 10 mrad due to space charge repulsion among the beamlets and magnetic fields, which resulted in excess heat loads of more than 20 kW/cm2 at the grounded grid. To compensate for beamlet deflections, an aperture offset and field shaping plate were designed.

Keywords

ITER, NBI, accelerator, negative ion beam, space charge, beam deflection

DOI: 10.1585/pfr.5.S2097

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References

  • [1] ITER EDA Final Design Report, ITER technical basis, Plant Description Document (PDD), G A0 FDR 1 01-07-13 R1.0, IAEA EDA doc. No. 24 (2002).
  • [2] M. Kashiwagi et al., Nucl. Fusion 49, 065008 (2009).
  • [3] T. Inoue, JAERI-Tech 94-007 (1994).
  • [4] M. Taniguchi et al., Rev. Sci. Instrum. 79, 02C110 (2008).
  • [5] M. Taniguchi et al., Rev. Sci. Instrum. 81, 02B101 (2010).
  • [6] N. Umeda et al., J. Plasma Fusion Res. 9, 259 (2010).
  • [7] M. Kashiwagi et al., AIP conference proceedings 1097, 421 (2008).
  • [8] M. Kashiwagi et al., Rev. Sci. Instrum. 81, 02B113 (2010).
  • [9] Cobham Technical Service Co. Ltd., Vector Fields software, http://www.vectorfields.com/.
  • [10] Y. Ohara, JAERI-M6757 (1976).
  • [11] T. Inoue et al., Rev. Sci. Instrum. 75, 1819 (2004).
  • [12] T. Mizuno et al., Rev. Sci. Instrum. 81, 02B103 (2010).
  • [13] T. Inoue et al., JAERI-Tech 2000-023 (2000).
  • [14] M. Kamada et al., Rev. Sci. Instrum. 79, 02C114 (2008).
  • [15] H. P. L de Esch et al., Fusion. Eng. Des. 84, 669 (2009).

This paper may be cited as follows:

Mieko KASHIWAGI, Masaki TANIGUCHI, Naotaka UMEDA, Takatoshi MIZUNO, Hiroyuki TOBARI, Masayuki DAIRAKU, Kazuhiro WATANABE and Takashi INOUE, Plasma Fusion Res. 5, S2097 (2010).