Physical sputtering and reflection processes in plasma-wall interactions
The current status of sputtering of and reflection from pure elements regarded as possible wall or divertor materials is reviewed for bombardment with hydrogen isotopes and self-ions. The general behaviour of sputtering and reflection on the projectile energy and angle of incidence as well as surface roughness is discussed. In a fusion machine the atoms bombarding the walls and divertor plates have a broad energy and angular distribution; therefore, computer simulation is used to study the dependence on a Maxwellian projectile distribution as a function of the edge plasma temperature which may be a more relevant description of the situation in a plasma machine. The case of multicomponent targets is more difficult and each system has to be studied individually. Preferential sputtering, usually the preferred emission of the lighter target species, changes the surface composition. A few examples demonstrate the change of surface composition, sputtering and reflection, and depth profiles with fluence (time). Simultaneous bombardment with more than one species further complicates the situation, where an erosion dominated regime can change into a deposition dominated regime with time.
Bibliographic Reference: Article: Journal of Nuclear Materials, Vol. 248 (1997) pp. 1-8
Record Number: 199711619 / Last updated on: 1997-12-09
Original language: en
Available languages: en