Plasma and Fusion Research

Volume 5, S2009 (2010)

Regular Articles

Plasma-Wall Interaction Study towards the Steady State Operation

Mizuki SAKAMOTO, Yuta HIGASHIZONO, Hideki ZUSHI, Kazuo NAKAMURA, Kazuaki HANADA, Hiroshi IDEI, Makoto HASEGAWA, Younosuke NAKASHIMA¹⁾, Masayuki TOKITANI²⁾, Mitsutaka MIYAMOTO³⁾, Kazutoshi TOKUNAGA, Shoji KAWASAKI, Hisatoshi NAKASHIMA, Tadashi FUJIWARA, Aki HIGASHIJIMA, Naoaki YOSHIDA and Kohnosuke SATO

: Research Institute for Applied Mechanics, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka 816-8580, Japan
1): Plasma Research Center, Tsukuba University, Ibaraki 305-8577, Japan
2): National Institute for Fusion Science, 322-6 Oroshi-cho, Toki, Gifu 509-5292, Japan
3): Department of Material Science, Shimane University, Matsue, Shimane 690-8504, Japan

(Received 21 December 2009 / Accepted 29 March 2010 / Published 10 December 2010)

Abstract

Various phenomena of plasma-wall interactions during long duration discharges in TRIAM-1M are investigated from macroscopic and microscopic viewpoints. It is found that the density dependence of the hydrogen neutral flux decay length is not very sensitive to the density (i.e. n_e^−0.2 ). Neutral transport through the scrape-off layer is important for structural formation of hydrogen recycling. The hydrogen retention in the co-deposited layer, which was obtained using a material probe during long duration discharges, is consistent with the global wall pumping rate estimated from particle balance analysis. The wall temperature and co-deposition play important roles on hydrogen re-emission and hydrogen absorption, respectively. Oxygen impurities should affect the erosion and deposition properties of the plasma-facing wall as well as the hydrogen retention property of the co-deposited layer. The co-deposition of hydrogen with molybdenum and the oxygen impurities both play important roles in the hydrogen recycling.

Keywords

plasma-wall interaction, steady state operation, tokamak, hydrogen recycling, co-deposition

DOI: 10.1585/pfr.5.S2009

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References

[1] M. Shimada et al., J. Nucl. Mater. 337-339, 808 (2005).
[2] V. Philipps, Physica Scripta T123, 24 (2006).
[3] E. Tsitrone, J. Nucl. Mater. 363-365, 12 (2007).
[4] T. Hirai et al., J. Nucl. Mater. 283-287, 1177 (2000).
[5] T. Hirai et al., J. Nucl. Mater. 290-293, 94 (2001).
[6] M. Sakamoto et al., Nucl. Fusion 42, 165 (2002).
[7] M. Sakamoto et al., J. Nucl. Mater. 313-316, 519 (2003).
[8] Y. Hirooka et al., J. Nucl. Mater. 313-316, 588 (2003).
[9] M. Sakamoto et al., Nucl. Fusion 44, 693 (2004).
[10] H. Zushi et al., Nucl. Fusion 45, S142 (2005).
[11] K. Hanada et al., Fusion Eng. Des. 81, 2257 (2006).
[12] M. Miyamoto et al., J. Nucl. Mater. 313-316, 82 (2003).
[13] M. Miyamoto et al., J. Nucl. Mater. 337-339, 436 (2005).
[14] M. Tokitani et al, J. Nucl. Mater. 367-370, 1487 (2007).
[15] M. Ogawa et al., J. Nucl. Mater. 363-365, 1364 (2007).
[16] R. Bhattacharyay et al., Nucl. Fusion 47, 864 (2007).
[17] M. Sakamoto et al., J. Nucl. Mater. 363-365, 233 (2007).
[18] E. Jotaki and S. Itoh, Fusion Eng. Des. 36, 447 (1997).
[19] K. Hanada et al., Fusion Eng. Des. 54, 79 (2001).
[20] D. Heifetz, D. Post, M. Petravic et al., J. Comput. Phys. 46, 309 (1982).
[21] E. Tsitrone et al., Plasma Phys. Control. Fusion 44, 701 (2002).
[22] T. Loarer et al., Nucl. Fusion 47, 1112 (2007).
[23] T. Nakano et al., J. Nucl. Mater. 363-365, 1315 (2007).
[24] T. Nakano et al., Nucl. Fusion 48, 085002 (2008).
[25] F. Weschenfelder, P. Wienhold and J. Winter, J. Nucl. Mater. 196-198, 1101 (1992).

This paper may be cited as follows:

Mizuki SAKAMOTO, Yuta HIGASHIZONO, Hideki ZUSHI, Kazuo NAKAMURA, Kazuaki HANADA, Hiroshi IDEI, Makoto HASEGAWA, Younosuke NAKASHIMA, Masayuki TOKITANI, Mitsutaka MIYAMOTO, Kazutoshi TOKUNAGA, Shoji KAWASAKI, Hisatoshi NAKASHIMA, Tadashi FUJIWARA, Aki HIGASHIJIMA, Naoaki YOSHIDA and Kohnosuke SATO, Plasma Fusion Res. 5, S2009 (2010).