FOM Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, Trilateral Euregio Cluster, Edisonbaan 14, Nieuwegein, The Netherlands.
Phys Chem Chem Phys. 2009 Nov 14;11(42):9823-30. doi: 10.1039/b908389h. Epub 2009 Aug 19.
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, C(2)H and C(2)H(2) 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.
我们通过分子动力学（MD）研究了在 10(28)离子/平方米/秒及更高通量下的高通量区域中碳侵蚀产额和表面氢富集的通量依赖性。我们模拟了在表面温度为 700 和 1000 K 时，用 10 eV 能量的高通量氢轰击的非晶氢化碳样品。采用 Brenner-Beardmore 的反应经验键序势作为相互作用势能，并使用 Berendsen 恒温器模拟能量耗散。模拟结果表明，较高的样品温度会导致较高的碳侵蚀产额，但对氢通量的依赖性不强。因此，在模拟中观察到的上表面层的氢富集不太可能导致实验中侵蚀产额的降低。此外，对于较高的通量，侵蚀材料的组成中 CH、C(2)H 和 C(2)H(2)略有增加，而含有更多氢、C 原子和 C(2)的物质减少。然而，侵蚀材料中的 H:C 比没有通量依赖性。
