Speaker
Description
This work presents an extensive SOLPS-ITER validation effort on the TCV tokamak, built around a global, multi-diagnostic comparison between simulations and systematic experimental databases. Accurate modelling of the scrape-off layer (SOL) and divertor plasma is essential for predicting wall erosion, impurity transport, and heat dissipation in present and future tokamaks. Quantitatively validating these models against experiments is therefore a prerequisite for reliable extrapolation to ITER-scale devices and for informing power-exhaust solutions in next-generation reactors.
In typical L-mode plasmas, SOLPS-ITER reproduces TCV conditions with consistently good accuracy across different divertor closures, matching upstream, divertor-leg and target profiles, the degree of detachment, and divertor neutral pressure. A key advancement is the first direct comparison between simulated and experimentally measured parallel flows in the divertor, made possible by the new tangential divertor spectroscopy system. The agreement significantly strengthens confidence in the modelled SOL flows and in the implementation of the drift physics.
Building on this validated L-mode baseline, the analysis is extended to the inter-ELM phase of type-I ELMy H-mode plasmas. A dedicated H-mode experimental database was developed with the same magnetic equilibrium as the L-mode set and a low ELM frequency (~60-120 Hz), enabling detailed diagnostic characterisation of the inter-ELM phase. By comparing L- and H-mode discharges at matched upstream density, the study isolates the impact of the edge transport barrier on power exhaust. In the modelling, a pedestal-like temperature and density structure is reproduced by locally reducing the anomalous cross-field diffusivities, χₑ and Dₙ, near the separatrix. This approach allows the resulting differences in target profiles to be quantitatively assessed and directly compared to experiments. The role of neutral compression in the divertor is quantified by comparing both L-mode and H-mode scenarios in baffled and unbaffled TCV configurations.
Enabled by controlled experiments in a mid-size tokamak, this work establishes a robust validation methodology applicable to other devices. It represents a significant step toward predictive, validated edge-plasma modelling for the design and optimisation of future fusion reactors.