ELM-induced melting: assessment of shallow melt layer damage and the power handling capability of tungsten in a linear plasma device

0427950 - ÚFP 2015 RIV GB eng J - Journal Article
Morgan, T.W. - van Eden, G.G. - de Kruif, T.M. - van den Berg, A. - Matějíček, Jiří - Chráska, Tomáš - De Temmerman, G.
ELM-induced melting: assessment of shallow melt layer damage and the power handling capability of tungsten in a linear plasma device.
Physica Scripta. -, T159 (2014), s. 014022-014022. ISSN 0031-8949. E-ISSN 1402-4896.
[International Conference on Plasma-Facing Materials and Components for Fusion Applications/14./. Jülich, 13.05.2013-17.05.2013]
Institutional support: RVO:61389021
Keywords : melting * tungsten * ELMs * divertor * ITER * DEMO
Subject RIV: JG - Metallurgy
Impact factor: 1.126, year: 2014
http://iopscience.iop.org/1402-4896/2014/T159/014022/pdf/1402-4896_2014_T159_014022.pdf

Tungsten samples were exposed to combined steady state and edge localised mode transient replication experiments in a linear plasma device; either in combined hydrogen plasma and high powered laser exposures at Magnum-PSI or steady state hydrogen plasma and superimposed plasma pulses created using a capacitor bank in Pilot-PSI. With each transient the surface temperature of the sample was elevated above the melting point creating a shallow molten layer. An apparent heat transport reduction in the near surface layer increases as a function of pulse number. Scanning electron microscopy analysis of the samples shows large scale grain enlargement down to several hundred to thousand micrometers below the surfaře as well as melt layer motion due to evaporative recoil from the molten surface. In the ITER divertor this would lead to severe embrittlement and enhanced erosion of the tungsten surfaře leading to reduced lifetimes for the plasma facing material.
Permanent Link: http://hdl.handle.net/11104/0233392