Regular Articles

Full Text / References

Characterization of Ion Cyclotron Wall Conditioning Using Material Probes in LHD

Naoko ASHIKAWA, Masayuki TOKITANI, Mitsutaka MIYAMOTO¹⁾, Hirotomo IWAKIRI²⁾, Naoaki YOSHIDA³⁾, Masaki NISHIURA, Mitsutaka ISOBE, Suguru MASUZAKI, Takeo MUROGA, Kenji SAITO, Tetsuo SEKI, Ryuhei KUMAZAWA, Hiroshi KASAHARA, Takashi MUTOH and the LHD experimental group

National Institute for Fusion Science, Toki 509-5292, Japan

1)

Shimane University, Matsue 690-8504, Japan

2)

Ryukyu University, Naha 903-0213, Japan

3)

Kyushu University, Kasuga 816-8580, Japan

(Received 28 December 2010 / Accepted 9 August 2011 / Published 11 November 2011)

Abstract

The ion cyclotron wall conditioning (ICWC) is one of the conditioning methods to reduce impurities and to remove tritium from the plasma facing components. Among the advantages of ICWC are the possible operation under strong magnetic field for fully torus area based on the charge exchange damage observed in thin SS samples arranged on a hexahxedron block holder with three different facings, the areas influenced by ICWC is estimated. On the plasma facing area of the material holder, high density of helium bubbles is observed by transmission electron microscope (TEM). But the other areas show no observable damage. The fact that the bubble were observed only in a sample facing the plasma implies that the effective particles, most probably charge exchange neutrals come to the wall straightly Thus, cleaning of the surfaces un-exposed to plasma directly and those in shadow area is difficult by ICWC.

Copyright (c) 2011 The Japan Society of Plasma Science and Nuclear Fusion Research

Keywords

LHD, wall conditioning, RF plasma, TEM, T inventory

DOI: 10.1585/pfr.6.2402138

Full Text

PDF format (1.0Mbytes)

References

• [1] A. Lyssoivan et al., J. Nucl. Mater. 337-339, 456 (2005).
• [2] E de la Cal and E. Gauthier, Plasma Phys. Control. Fusion 47, 197 (2005).
• [3] H. Esser et al., J. Nucl. Mater. 266-269, 240 (1999).
• [4] E. Gauthier et al., J. Nucl. Mater. 241-243, 553 (1997).
• [5] J.K. Xie et al., J. Nucl. Mater. 290-293, 1155 (2001).
• [6] K. Saito et al., J. Nucl. Mater. 337-339, 145 (2005).
• [7] T. Mutoh et al., Nucl. Fusion 43, 738 (2003).
• [8] S. Masuzaki et al., Fusion Sci. Technol. 58, 297 (2010).
• [9] N. Ashikawa et al., Fusion Eng. Des. 81, 2831 (2006).
• [10] E. Tsitrone et al., Nucl. Fusion 49, 075011 (2009).
• [11] M. Isobe et al., Review of Scientific Instrument 72, 611 (2001).

This paper may be cited as follows:

Naoko ASHIKAWA, Masayuki TOKITANI, Mitsutaka MIYAMOTO, Hirotomo IWAKIRI, Naoaki YOSHIDA, Masaki NISHIURA, Mitsutaka ISOBE, Suguru MASUZAKI, Takeo MUROGA, Kenji SAITO, Tetsuo SEKI, Ryuhei KUMAZAWA, Hiroshi KASAHARA, Takashi MUTOH and the LHD experimental group, Plasma Fusion Res. 6, 2402138 (2011).