ヘリウムプラズマ照射により高融点金属表面に形成されたナノ構造

Abstract

Helium defects on plasma-facing refractory metals like tungsten have been studied in fusion sciences from the view point of the effects on metal surface properties, concentrating on the bubble formation. However， the surface morphology over the lower surface temperatue range was found recentiy to be changed drastically， something like cotton down or arborescence，sometimes called as “fuzz". The formation process， although still open problem， would be discussed in terms of viscoelastic model with the effect of surface tension， taking account of its thermal properties and nano-bubbles inside the thin fibers. Some physical surface characteristics like electron emission， radiation emissivity and sputtering are quite influenced by its forest-like structure. Unipolar arcing has been newly studied by using such a surface structure which makes its initiation controllable. In the present report， other examples of nanostructure formation in a variety of particle incident conditions have been introduced as well as the possibility of its industrial applications to enhance interdisciplinary interests.