[Table of Contents]

Plasma and Fusion Research

Volume 5, S2102 (2010)

Regular Articles


Optical Measurement of Cesium Behavior in a Large H Ion Source for a Neutral Beam Injector
Katsunori IKEDA, Kenichi NAGAOKA, Yasuhiko TAKEIRI, Katsuyoshi TSUMORI, Masaki OSAKABE, Haruhisa NAKANO and Osamu KANEKO
National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292, Japan
(Received 25 December 2009 / Accepted 24 March 2010 / Published 10 December 2010)

Abstract

Optical emission in a negative hydrogen ion source for the Large Helical Device Neutral Beam Injector (LHD-NBI) has been measured to investigate the behavior of Cs. Two optical sight lines exist parallel to the plasma grid, in the discharge area and in the magnetic filter area near the plasma grid. In the discharge area, the spectrum intensity from Cs+ ions is considerably increased during 20 s of the beam extraction. This indicates a considerable increase in the Cs+ density inside the plasma due to the impact of back-streaming H+ ions. A strong neutral Cs spectrum is observed in the magnetic filter area, where the electron density is lower than in the discharge area. The rate of increase of neutral Cs is much enhanced after t = 30 s, probably because the Cs adsorbed on the cooled region inside the arc chamber evaporates because its temperature increases during the long pulse discharge.


Keywords

neutral beam injector, negative ion source, cesium, arc discharge

DOI: 10.1585/pfr.5.S2012


References

  • [1] M. Kuriyama, N. Akino, N. Ebisawa et al., J. Nucl. Sci. Technol. 35 (11), 739 (1998).
  • [2] Y. Takeiri, O. Kaneko, K. Tsumori et al., Nucl. Fusion 46, S199 (2006).
  • [3] E. Speth, H. D. Falter, P. Franzen et al., Nucl. Fusion 46, S220 (2006).
  • [4] R. S. Hemsworth, A. Tanga and V. Antoni, Rev. Sci. Instrum. 79, 02C109 (2008).
  • [5] K. Ikeda, K. Nagaoka, Y. Takeiri et al., Plasma Science and Technology 11 (4), 452 (2009).
  • [6] Y. Takeiri, O. Kaneko, K. Tsumori et al., Rev. Sci. Instrum. 71 (2), 1225 (2000).
  • [7] D. Marcuzzi, M. Dalla Palma, M. Paveia et al., Fusion Eng. Des. 84, 1253 (2009).
  • [8] U. Fantz, H. Falter, P. Franzen et al., Nucl. Fusion 46, S297 (2006).
  • [9] K. Ikeda, K. Nagaoka, Y. Takeiri et al., Rev. Sci. Instrum. 79, 02A518 (2008).
  • [10] K. Ikeda, U. Fantz, K. Nagaoka et al., Plasma Fusion Res. 2, S1047 (2007).
  • [11] U. Fantz, H. D. Falter, P. Franzen et al., Fusion Eng. Des. 74, 299 (2005).
  • [12] P. S. Ganas, J. Chem. Phys. 76, 2103 (1982).

This paper may be cited as follows:

Katsunori IKEDA, Kenichi NAGAOKA, Yasuhiko TAKEIRI, Katsuyoshi TSUMORI, Masaki OSAKABE, Haruhisa NAKANO and Osamu KANEKO, Plasma Fusion Res. 5, S2102 (2010).