[Table of Contents]

Plasma and Fusion Research

Volume 2, 009 (2007)

Rapid Communications

Alleviation of Helium Holes/Bubbles on Tungsten Surface by Use of Transient Heat Load
Shin KAJITA, Shuichi TAKAMURA, Noriyasu OHNO1) and Tentaro NISHIMOTO2)
Graduate School of Engineering, Nagoya University
1)
EcoTopia Science Institute, Nagoya University
2)
Department of Engineering, Nagoya University
(Received 30 October 2006 / Accepted 12 March 2007 / Published 24 April 2007)

Abstract

The alleviation effect of transient heat load on helium holes/bubbles has been demonstrated using ruby laser pulses for the transient heat source in the divertor simulator NAGDIS-II. It is shown that the holes and bubbles disappeared following the irradiation of the ruby laser pulses, while the surface roughness was significantly enhanced by the irradiation of the Nd:YAG laser pulses. Based on the numerically calculated temperature in the specimen, the physical mechanism causing this difference is discussed particularly in terms of pulse width (0.6 ms for ruby laser without a Q-switch and 5 ns for Nd:YAG laser with a Q-switch).

Keywords

tungsten, holes and bubbles, divertor simulator, heat conduction, laser irradiation, transient heat load

DOI: 10.1585/pfr.2.009

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References

  • [1] G. Federici et al., Plasma Phys. Control. Fusion 45, 1523 (2003).
  • [2] G. Federici et al., J. Nucl. Mater. 337-339, 684 (2005).
  • [3] M.Y. Ye et al., J. Nucl. Mater. 241-243, 1243 (1997).
  • [4] H. Iwakiri et al., J. Nucl. Mater. 283-287, 1134 (2000).
  • [5] N. Ohno et al., J. Nucl. Mater. (in press).
  • [6] S. Kajita et al., J. Plasma Fusion Res. 81, 745 (2005).
  • [7] D. Nishijima et al., J. Nucl. Mater. 329-333, 1029 (2004).
  • [8] S. Kajita et al., J. Appl. Phys. 100, 103304 (2006).
  • [9] I. Garkusha et al., J. Nucl. Mater. 337-339, 707 (2005).
  • [10] M. Ye et al., J. Plasma Fusion Res. SERIES 3, 265 (2000).

This paper may be cited as follows:

Shin KAJITA, Shuichi TAKAMURA, Noriyasu OHNO and Tentaro NISHIMOTO, Plasma Fusion Res. 2, 009 (2007).