Steady-State and Dynamic Validation of DIV1D with SOLPS-ITER and MAST-U Experiments

Future fusion reactors will require real-time detachment control to maintain divertor heat and particle fluxes within material limits. Here, we assess the time-dependent 1D scrape-off-layer model DIV1D as a reduced-order plant model for detachment controller design by benchmarking its steady-state predictions and control-relevant dynamics for a MAST-U H-mode scenario, respectively, against SOLPS-ITER simulations and experimental data. After tuning a small set of free parameters, DIV1D reproduces the main quantities from 1D mapped SOLPS profiles. Density-ramp and molecular-puffing scans show that DIV1D captures the trends in key target quantities. Multi-sine system-identification simulations show that baseline DIV1D responds faster than MAST-U system-identification experiments [1]. The agreement improves substantially when the total particle throughput is reduced to experimentally representative levels. This result demonstrates that the total particle throughput in the global particle balance is a key determinant of the modeled control-relevant dynamics and must be represented accurately for reliable plant-model behavior. These findings establish DIV1D as a useful tool for model-based detachment controller design on MAST-U, with direct relevance to next-step devices, where experimental system-identification opportunities will be limited and reduced-order models will be essential for pre-operational controller development.