Development of DTT single null divertor scenario

This paper focuses on scrape-off layer and divertor modelling of the medium-density single-null scenario of the Divertor Test Tokamak facility (DTT), under construction in Italy. The modelling was performed using the 2D coupled fluid-Monte Carlo code SOLEDGE2D-EIRENE. For DTT pump designing, neutral pressure at the pump aperture below the dome is calculated in deuterium-only cases as well as with impurity seeding with various puffing levels. This scenario analysis also allowed the characterization of detachment in DTT and the influence of pumping on detachment itself. Two different radiating impurities, neon and nitrogen, were tested in the high power scenario to evaluate the minimum impurity concentration required to achieve sustainable conditions at DTT divertor. The sensitivity of the model was studied by varying the impurity concentration; the model shows a hysteresis-like behaviour between the impurity influx and the total impurity content by which detachment is strongly influenced.