This title appears in the Scientific Report : 2015 

Effect of High-flux H/He Plasma Exposure on Tungsten Damage Due to Transient Heat Loads
De Temmerman, G. (Corresponding author)
Morgan, T. W. / van Eden, G. G. / de Kruif, T. / Wirtz, M. / Matejicek, J. / Chraska, T. / Pitts, R. A. / Wright, G. M.
Werkstoffstruktur und -eigenschaften; IEK-2
Journal of nuclear materials, 463 (2015) S. 198 - 201
Amsterdam [u.a.] Elsevier Science 2015
10.1016/j.jnucmat.2014.09.075
Journal Article
Plasma-Wall-Interaction
Please use the identifier: http://dx.doi.org/10.1016/j.jnucmat.2014.09.075 in citations.
The thermal shock behaviour of tungsten exposed to high-flux plasma is studied using a high-power laser. The cases of laser-only, sequential laser and hydrogen (H) plasma and simultaneous laser plus H plasma exposure are studied. H plasma exposure leads to an embrittlement of the material and the appearance of a crack network originating from the centre of the laser spot. Under simultaneous loading, significant surface melting is observed. In general, H plasma exposure lowers the heat flux parameter (FHF) for the onset of surface melting by ∼25%. In the case of He-modified (fuzzy) surfaces, strong surface deformations are observed already after 1000 laser pulses at moderate FHF = 19 MJ m−2 s−1/2, and a dense network of fine cracks is observed. These results indicate that high-fluence ITER-like plasma exposure influences the thermal shock properties of tungsten, lowering the permissible transient energy density beyond which macroscopic surface modifications begin to occur.