Description
The control of plasma-wall interactions (PWI) such as erosion and deposition of high-Z material, as well as the understanding of impurity migration are key challenges for stable operation of fusion devices. Plasma performance becomes critical once the core concentration of high-Z material is too high. To strengthen earlier findings in view of the change to a full tungsten (W) machine in the recent 2024 ITER re-baseline [1], and in support of impact estimates on burning plasma performance [2], refinement of the W source and influx assessments for a broad range of scenarios is an important exercise. Here, the 3D Monte-Carlo gyro-kinetic code ERO2.0 is applied to increase the sophistication of W erosion and subsequent migration simulations under both ion and charge-exchange neutral (CXN) impact.
This contribution presents an overview of the most-up-to-date ERO2.0 simulations of baseline neon (Ne)-seeded Q=10 H-mode plasmas for varying separatrix-averaged Ne concentrations. Plasma backgrounds for the simulations are provided by the latest wide-grid version of the SOLPS-ITER code, furnishing a much improved, self-consistent description of the scrape-off layer (SOL) plasma right up to the main chamber walls. Although CXN erosion is treated most accurately using bivariate energy- and angular-resolved distributions at the wall, the refined ERO2.0 simulations confirm the earlier findings in [1] that the W source is dominated by Ne sputtering with W self-sputtering the second largest contributor. The W core-plasma influx depends strongly on the SOL fuel ion flow patterns and on the assumptions regarding cross-field transport coefficients imposed in the modelling. To quantify the impact of the latter, simulations with pure anomalous transport are compared against a combination of anomalous and neoclassical transport. Neoclassical transport profiles for cross-field pinch and diffusion are incorporated from FACIT calculations based on local pedestal plasma conditions. In general, highest influxes are observed for W originating from main chamber panels, while the influx from the divertor is low, confirming the strong divertor screening found in previous studies.
[1] R. A. Pitts et al., NME 42, 101854 (2025)
[2] T. Wauters, plenary at this conference