München 2019 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 3: Plasma Surface Interaction I

P 3.3: Vortrag

Montag, 18. März 2019, 12:00–12:15, HS 21

Light reflection in the line shape of sputtered atoms of high-Z plasma facing components in the linear plasma device PSI-2 — •Stephan Ertmer, Oleksandr Marchuk, Sven Dickheuer, Arkadi Kreter, and Sebastijan Brezinsek — Forschungszentrum Jülich GmbH - Institut für Energie- und Klimaforschung - Plasmaphysik, Partner of the Trilateral Euregio Cluster (TEC), 52425 Jülich, Germany

Linear plasma devices like PSI-2 are useful tools to study plasmas-wall-interaction and test possible plasma facing materials. Spectroscopy is a powerful means to determine the particles fluxes, e.g. by S/XB values at the plasma edge. In the last decades enormous efforts are undertaken to improve the understand the underlying physics as well as experimental conditions. It is demonstrated in argon plasmas (T_e≈ 3 eV, n_e≈ 3.5·10¹² cm⁻³, E_ion =40−160 eV) that the light reflection at aluminum and tungsten surfaces has a strong impact on the line intensities and the line shapes of sputtered particles. Thus for instance the emission is increased by a factor two for line-of-sights terminating at surfaces. Moreover, the degradation of the optical properties of surfaces polished aluminum was detected in the line shape of emission by sputtered particles. The experiments are performed in PSI-2 plasmas, where other bordering mechanisms such as the Zeeman effect can be neglected because of a magnetic field in the order of 0.1 T. The clear difference between spectra observed at different lines-of-sight is detected. The studied effect must included in evaluating the S/XB values and existing codes such as ERO.