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Carbon Erosion and Dust Formation under Heavy Atomic Hydrogen Irradiation

Yuji TAKEGUCHI, Masaaki KYO, Yoshihiko UESUGI, Yasunori TANAKA and Suguru MASUZAKI¹⁾

Graduate School of Natural Science and Technology, Kanazawa University, Kakuma 920-1192, Japan

1)

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

(Received 24 January 2008 / Accepted 21 April 2008 / Published 28 May 2008)

Abstract

Experiments on erosion and dust formation on graphite materials have been performed using high power induction plasmas containing high atomic hydrogen flux (∼10²⁴ m^-2 s^-1 ). Chemical sputtering by atomic hydrogen irradiation with an incident energy below 1 eV eroded the graphite targets significantly, and the sputtering yield was roughly estimated to be 0.002-0.005, which is as high as that obtained by ion beam experiments. The transport of the released hydrocarbon along the gas flow results in carbon dust formation on the eroded graphite target and also on the silicon and graphite targets located at the remote position. The dust structure strongly depends on the target surface temperature, and the graphite dust turns into diamond crystals when the surface temperature rises to 1100 K.

Copyright (c) 2008 The Japan Society of Plasma Science and Nuclear Fusion Research

Keywords

plasma-surface interaction, dust formation, atomic hydrogen plasma, carbon material

DOI: 10.1585/pfr.3.025

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References

• [1] Y. Tanaka et al., Appl. Phys. Lett. 89, 031501 (2006).
• [2] S.A. Al-Mamun et al., IEEJ Trans. PE 128, 479 (2008).
• [3] E. Vietzke and A.A. Haasz, Chemical Erosion, in physical processes of the interaction of fusion plasmas with solids (Academic Press. Inc., San Diego, 1996) p.135.

This paper may be cited as follows:

Yuji TAKEGUCHI, Masaaki KYO, Yoshihiko UESUGI, Yasunori TANAKA and Suguru MASUZAKI, Plasma Fusion Res. 3, 025 (2008).