Benchmarking the global particle balance of DIV1D with SOLPS-ITER simulations on the Tokamak à Configuration Variable

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