Molecular dynamics simulations of amorphous hydrogenated carbon under high hydrogen fluxes

TitleMolecular dynamics simulations of amorphous hydrogenated carbon under high hydrogen fluxes
Publication TypeJournal Article
Year of Publication2009
AuthorsE.D de Rooij, U. von Toussaint, A.W Kleyn, W.J Goedheer
JournalPhysical Chemistry Chemical Physics
Volume11
Number42
Pagination9823-9830
Type of ArticleArticle
ISBN Number1463-9076
Accession NumberISI:000271033200026
KeywordsCHEMICAL EROSION, DEPENDENCE, films, GRAPHITE SURFACES, IMPACT, IONS, ITER, MODEL
Abstract

We study the flux dependence of the carbon erosion yield and the hydrogen enrichment of the surface in the high flux regime at 10(28) ions per m(2) s and higher by using molecular dynamics (MD). We simulate an amorphous hydrogenated carbon sample exposed to high flux hydrogen bombardment with a hydrogen energy of 10 eV at surface temperatures of 700 and 1000 K. As interaction potential the reactive empirical bond order potential of Brenner-Beardmore is taken and energy dissipation is simulated with the Berendsen thermostat. The simulation results show that the carbon erosion yield is higher for higher sample temperatures but does not show a strong dependence on the hydrogen flux. Hence, the hydrogen enrichment in the upper surface layer observed in the simulations most likely does not contribute to the erosion yield reduction in the experiments. Furthermore, the composition of the eroded material shows a slight increase in CH, C2H and C2H2 for higher fluxes, whereas species with more hydrogen, C atoms and C-2 are decreased. However, the H : C ratio in the eroded material shows no flux dependence.

URL<Go to ISI>://000271033200026
Division

Fusion Physics

PID

edafb52b138274e225dc5c3eeb47e7bb

Alternate TitlePhys. Chem. Chem. Phys.

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