@article{article,
  author = {S. P. Kobussen and S. Van den Kerkhof and F. Cursi and W. Dekeyser and G. L. Derks and B. Kool and D. Moulton and K. Verhaegh and M. van Berkel and S. Wiesen and MAST-U Team},
  title = {System identification simulations using the Advanced Fluid Neutral model and Wide Grid formalism in SOLPS-ITER},
  abstract = {This work presents a first step towards using the SOLPS-ITER code package for synthetic system identification using multisine perturbations. Numerical modelling is used to replicate system identification experiments performed to establish exhaust control done on MAST-U. These experiments involve perturbing the gas injection rate and observing the SOL response in the frequency domain. The model used is the Advanced Fluid Neutral (AFN) model of SOLPS-ITER, implemented in the Wide Grids (WG) version of the code. The grid was generated with the Grid Optimization and Adaptation Toolbox (GOAT) and extends to the vessel wall, to enable calculating fluid neutral parameters across the entire domain. New boundary condition types were implemented in the code to allow for multisine gas injection perturbations, as well as reservoir models for remote vessel regions without plasma. In steady state, it is possible to simulate plasmas ranging from attached to deeply detached using different gas injection rates. This allows for comparison between simulation and experimental results at similar levels of detachment. Comparison between simulation and experimental data in the frequency domain shows that the AFN SOLPS-ITER simulations predict faster response times to divertor fuelling perturbations than the experiments, likely in part due to the fluid approximation used for the neutrals. When including the reservoir models for remote vessel regions the phase shifts increase, but are still too low compared to experiments.},
  year = {2026},
  journal = {Nuclear Fusion},
  volume = {66},
  pages = {in press},
  publisher = {IOP Publishing},
  doi = {10.1088/1741-4326/aeb276},
  language = {eng},
}