Edge plasma codes, such as SOLPS, are widely used to study plasma transport in tokamaks scrape-off layers (SOL). The possibility to apply these codes to non hydrogenic plasmas and to linear plasma devices (LPDs) is gaining the interests of the fusion community. These facilities play a pivotal role in plasma-material interaction (PMI) studies for future fusion devices and may allow to test the code capabilities both in terms of geometry and simulated plasma species. In this contribution, we apply the SOLPS-ITER code for the simulations of Argon plasmas in the medium-flux linear machine GyM. A sensitivity scan over the pumping efficiency, transport coefficients and absorbed electron power was done, performing B2.5-EIRENE coupled simulations. A quantitative analysis of the different flux contributions is provided through the use of a twopoint modelling. Comparison with experiments shows a promising qualitative and quantitative agreement, with the sole exception of the simulated neutrals pressure. Dedicated EIRENE standalone simulations were performed to investigate this issue, also highlighting the role of neutral-neutral elastic collisions at high values of the puffing intensity.

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Surface morphology of plasma-facing components (PFCs) and its evolution during the plasma irradiation has shown to have a significant effect on the erosion and subsequent transport of sputtered particles in plasma. This in turn can influence the resulting lifetime of PFCs. A model for treatment of the surface roughness effect on the erosion of PFCs has been recently incorporated into the 3D Monte-Carlo ERO2.0 code. First simulations have confirmed significant influence of the assumed surface roughness (both regular and stochastic numerically constructed samples) on both the effective sputtering yields Yeff and the effective angular distributions of sputtered particles. In this study series of experiments at the linear plasma device PSI-2 are conducted to test the surface roughness effect on the sputtering parameters. Graphite samples prepared with 100 nm molybdenum (Mo) layer with various surface roughness characteristic size (Ra = 110 nm, 280 nm, 600 nm and Ra< 20 nm) were exposed to the helium (He) plasma in the PSI-2 linear plasma device at magnetic field of B=0.1T. These PSI-2 experiments were simulated using the ERO2.0 with surface morphology model. Simulations are able to reproduce the experimentally observed significant suppression of erosion for higher Ra values.

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Gross and net erosion of tungsten (W) and other plasma-facing materials in the divertor region have been investigated in deuterium (D) and helium (He) plasmas during dedicated experiments in L- and H-mode on ASDEX Upgrade and after full-length experimental campaigns on the WEST tokamak. Net erosion was determined via post-exposure analyses of plasma-exposed samples and full-size wall components, and we conclude that the same approach is applicable to gross erosion if marker structures with sub-millimeter dimensions are used to eliminate the contribution of prompt re-deposition. In H-mode plasmas, gross erosion during ELMs may exceed the situation in inter-ELM conditions by 1–2 orders of magnitude while net erosion is typically higher by a factor of 2–3. The largest impact on net erosion is attributed to the electron temperature while the role of the impurity mixtures is weaker, even though both on ASDEX Upgrade and WEST significant amounts of impurities are present in the edge plasmas. Impurities, on the other hand, will lead to the formation of thick co-deposited layers. We have also noted that with increasing surface roughness, net erosion is strongly suppressed and the growth of co-deposited layers is enhanced. In He plasmas, gross erosion is increased compared to D due to the higher mass and charge states of the plasma particles, resulting from larger energies due to sheath acceleration, but strong impurity fluxes can result in apparent net deposition in the divertor. Our results from ASDEX Upgrade and WEST are comparable and indicate typical net-erosion rates of 0.1–0.4 nm s−1, excluding the immediate vicinity of the strike-point regions.