SOLPS-ITER simulation of MAST-U and study of neutral dynamics

We present simulations of MAST-U with SOLPS-ITER to validate its results against camera data, along with an interpretive analysis of neutral dynamics. Understanding of the plasma edge in current tokamaks and the influence of neutrals on the performance is important, as this will change drastically as we move to FPPs like STEP. In those conditions, the core becomes opaque to the neutrals being fuelled, and the density will determine plasma control [1]. One method to study the neutrals is through SOLPS-ITER, which has been used to validate experimental data from Alcator C-Mod [3] and TCV-X21 [2]. We chose an H-mode MAST-U discharge with a connected double null and a conventional divertor configuration. Then it was modeled using SOLPS-ITER to obtain a neutral density distribution in the poloidal cross section, and we compared the neutral density with the experimental data from cameras. The focus was on the Balmer emissions through the camera. The particular discharge also includes gas puffing in the high-field side around midplane and extended diverter chamber, which is also modelled and studied with SOLPS-ITER.

References

[1] S. Mordijck 2020 Nucl. Fusion 60 082006

[2] Y. Wang et al 2024 Nucl. Fusion 64 056040

[3] S. Mordijck et al 2024 Nucl. Fusion 64 126034

This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Fusion Energy Sciences DE-SC0023372, DE-SC0021306, DE-SC0024624, DE-SC0023289 and partly supported by the EPSRC Energy Programme [grant number EP/W006839/1]