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In the EAST radiative divertor experiments, stable detachment and divertor protection have been achieved with mixed impurity gas seeding. Experiments indicate that neon (Ne) is an appropriate external impurity for plasma detachment in EAST. In this work, the physical mechanism of plasma detachment with Ne seeding in EAST is studied by using the SOLPS-ITER code package. The electron temperature Tet on the upper outer divertor target decreases to below 10 eV with Ne seeding, which is mainly due to the power loss and upstream power drop caused by the impurity radiation. For Tet < 10 eV, the significant drop of the poloidal saturation ion current js,p occurs around the upper outer strike point. The simulation results show that the js,p drop is mainly driven by the rise of the momentum loss and the upstream pressure loss. The increase in the momentum loss is mainly caused by the plasma–neutral interactions in the region from the X-point to the upper outer divertor target. The upstream pressure loss around the X-point is related to the decrease in the upstream electron temperature Teu, which originates from the increased radiation loss with Ne seeding. [ABSTRACT FROM AUTHOR]

Steady-state heat flux deposition on the first wall of the Chinese Fusion Engineering Testing Reactor (CFETR) is investigated for 1 GW fusion power and under the updated design scheme. The computation is accomplished by the modelling of two simulation systems: SOLPS-ITER and PFCFlux. Seeding neon (Ne) gas is considered to be one of the possible methods of protecting the CFETR divertor from high heat flux damage. Simulations with different Ne seeding rates were carried out on a standard divertor with a lower single-null configuration to determine the effect of Ne seeding on heat flux deposition on the first wall. A blob-based transport model was used to investigate the effect of enhanced cross-field transport on the CFETR first wall, as with ITER and EU DEMO simulations. This work establishes a potential method for simulating the complete heat flux deposition on the first wall for the CFETR steady state by SOLPS-ITER and PFCFlux. After modelling and energy analysis, the peak value of complete heat flux on each module of the CFETR first wall is obtained, which may provide the basic reference for the CFETR physics and engineering design team. The CFETR first wall module which receives the highest heat flux has also been identified, and Ne seeding has a positive effect on reducing the heat flux on the CFETR first wall from around 2.5 MW m−2 to 1 MW m−2, which is within the engineering requirement. [ABSTRACT FROM AUTHOR]