Helium effects on tungsten under fusion-relevant plasma loading conditions

Experiments were performed in the Pilot-PSI linear plasma device to study the formation of helium-induced nanostructures under high heat fluxes (>10MWm−2), the erosion of a tungsten surface at the elevated temperatures where those structures typically form and most importantly the behavior of a h...

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Bibliographic Details
Published in:Journal of nuclear materials 2013-07, Vol.438, p.S78-S83
Main Authors: De Temmerman, G., Bystrov, K., Doerner, R.P., Marot, L., Wright, G.M., Woller, K.B., Whyte, D.G., Zielinski, J.J.
Format: Article
Language:English
Subjects:
Correlation
Erosion
Fluxes
Helium
Nanostructure
Sputtering
Tungsten
Voids
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Summary:Experiments were performed in the Pilot-PSI linear plasma device to study the formation of helium-induced nanostructures under high heat fluxes (>10MWm−2), the erosion of a tungsten surface at the elevated temperatures where those structures typically form and most importantly the behavior of a helium-induced fibreform structure during ELM-like pulses. A strong correlation between the characteristic size of the helium-induced morphology and the size of the voids observed in the near-surface region has been found, and both increase in size with increasing temperatures. Temperature-dependent erosion of tungsten surfaces was observed despite the ion energy being below the sputtering threshold, with an exponential increase of the erosion for temperatures higher than 2400°C. The same effect was observed during ELM-like plasma pulses. Finally, a complete disappearance of the tungsten fibreform structure was observed after only one plasma pulse for energy densities higher than 0.5MJm−2.
ISSN:0022-3115
1873-4820
DOI:10.1016/j.jnucmat.2013.01.012