Pisces-RF: A helicon-plasma based linear-device for the study of fusion relevant plasma-materials-interactions
M.J. Baldwin, D. Nishijima, M.I. Patino, G. Gunner, T. Lynch, F. Chang, M.J. Simmonds, A. Založnik, Sue E. Moore, B. Schwendeman, R. Ciamacco, R. Doerner, George Tynan
Abstract
The helicon-plasma based-linear plasma-materials-interaction device, Pisces-RF is introduced. Steady-state plasma parameters in the target region are electron density up to ∼1019 m−3, electron temperature up to ∼10 eV, and ion flux up to ∼1023 m−2s−1 in D2 and He, with an associated maximum peak target heat flux of ∼1 MWm−2 and a few MWm−2 when accelerating ions with an electrical bias. Attached and detached target plasma regimes with both gaseous species can be achieved, as characterized by high and low Te (<1eV) plasmas with high fractions of singly ionized atomic ions. The downstream target plasma is inferred to have a low concentration of condensing or sticking impurity ions (< 0.1 ppb), as confirmed by accumulation experiments on electrically-floating targets in deposition-dominated low Te plasma conditions. The validation of Pisces-RF target PMI on W is confirmed by the observation of D retention values and W fuzz-layer thicknesses, obtained in D2 and He plasmas, that are in good agreement with prior literature. Lastly, the integration of Pisces-RF with a tandem ion-accelerator, to study the synergistic effects of simultaneous displacement damage and plasma irradiation, which we refer to as burning-plasma-material-interaction (BPMI), is discussed.