Numerical analysis of incident angle of heavy metal impurity to plasma facing components by IMPGYRO

Hoshino, Kazuo; Toma, Mitsunori*; Furubayashi, Masahiko*; Hatayama, Akiyoshi*; Inai, Kensuke*; Oya, Kaoru*

Journal of Nuclear Materials, 390-391, p.168 - 171, 2009/06

https://doi.org/10.1016/j.jnucmat.2009.01.159

The self-sputtering yield and the reflection yield are important for a prediction of the tungsten impurity content penetrating into the main plasma in future fusion reactors. These yields greatly depend on the incident angle of impurities to the plasma facing components. The IMPGYRO code is applied to the analysis of the angle distribution of incident impurities and the effect of the incident angle and energy on the sputtering and reflection yields. The incident angle distribution is divided into several peaks corresponding to charge states. This is caused by the different acceleration for each charge state by the sheath. In the attached plasma case, the sheath increases the self-sputtering yield. This is due to the change of the incident angle by the sheath rather than the change of the incident energy. On the other hand, in the detached plasma case, the significant effects of the sheath on the sputtering yield and the reflection yield is not seen.