TY  - EJOUR
AU  - Möller, Sören
AU  - Hubeny, Michael
AU  - Unterberg, Bernhard
AU  - Wegener, Tobias
AU  - Reinhart, Michael
AU  - Kreter, Arkadi
AU  - Petersson, Per
TI  - Plasma impurities in linear, hot cathode, arc-plasma devices studied with D2 and He-plasmas in PSI-2
M1  - FZJ-2019-02056
PY  - 2019
AB  - Linear plasma devices are being used for studies of plasma-surface interaction. Hot-cathode arc-discharge devices such as PSI-2 can provide flux densities in the 10^23 ions/m²s order at electron temperatures of 1-20eV. In magnetic confinement nuclear fusion science, linear plasma devices are employed instead of confinement devices due to their well-defined conditions and similar plasma parameters as observed in tokamak edge plasmas. This study aims to further improve the knowledge of the exposure conditions by analysing impurities unintentionally released into the PSI-2 plasma and their subsequent deposition on target surfaces. The analysis is conducted with D2 and He plasmas using Langmuir probes and surface analysis of Si catcher samples. Deposited impurity fluxes up to 2*10^17/m²s=6µg/m²s or about 10^-5 of the plasma flux density are found. Oxygen constitutes about 90atom% to the impurities. Experiments with two leak rates indicate a connection between base pressure and oxygen deposition rate. Modelling points on the residual gas, cathode, Mo-anode, and the steel vacuum vessel as impurity sources. Implications of the impurity fluxes for hydrogen retention, mass-loss, and sputtering related studies are derived.
LB  - PUB:(DE-HGF)25
UR  - https://juser.fz-juelich.de/record/861610
ER  -