Benchmarking the global particle balance of DIV1D with SOLPS-ITER simulations on the tokamak à configuration variable

Abstract This paper investigates the global particle balance of DIV1D, a 1D scrape-off layer (SOL) model extended with reservoirs for neutrals outside the plasma and for the core particle content. The aim of DIV1D is to capture the global particle balance and SOL solutions as a function of gas puffing. To this end, DIV1D is calibrated on solutions of 1D mapped SOLPS-ITER simulations for a density ramp on the tokamak à configuration variable. In this density ramp (as a function of core ion fluxes and reservoir densities) DIV1D predictions for upstream plasma density, upstream electron temperature, target ion flux and target heat flux align mostly within confidence intervals of mapped 1D SOLPS-ITER solutions. For low upstream densities, the target temperature is overestimated by 2 to 4 eV. Simulating the global particle balance as a function of molecular puffing, DIV1D recovers upstream plasma densities and reservoir atomic densities while the core density sensitivity is overestimated by a factor six, whereas sensitivities of divertor reservoir molecular densities are underestimated by a factor three. Special attention is given to wall association effects outside the plasma and SOL opacity in achieving imperfect but acceptable agreement with mapped SOLPS-ITER solutions.