Molecular dynamics simulations of temperature effect on tungsten sputtering yields under helium bombardment

• 来源期刊: 中国科学:物理学 力学 天文学（英文版）
• 年，卷（期）: 2018,（1）
• 页码范围: 72-75
• 页数: 4页
• 语种: 英文
• DOI: 10.1007/s11433-017-9109-8

摘要

Tungsten is the most promising plasma-facing material (PFM) for future nuclear fusion reactors such as international thermonuclear experimental reactor (ITER) owing to its high melting temperature,high thermal conductivity and low hydrogen retention [1].Under ITER-relevant conditions,a large amount of helium from the fusion reactions will constantly bombard the PFM.Though the energies of helium atoms in different regions are different,the flux and energy of helium at the PFM are expected to be approximately 1020-1022 particles/(m2 s) and ＜500 eV [2].Helium irradiation can lead to the formation of nanoscale defects [3] and a high density of helium nano-bubbles in the near-surface of tungsten [4],the growth of which may induce changes of the surface morphology,such as the formation of wave-like nanostructures [5] and nano-fuzzes [6].The threshold energy for helium to sputter tungsten is in the range of 105-110 eV [7].The sputtering yields of tungsten are very low,but the accumulation of physical sputtering over time will induce surface erosion,further resulting in components destruction and plasma instability [4].