Simulation of neutral gas flow in a tokamak divertor using the Direct Simulation Monte Carlo method

• Subdivertor gas flows calculations in tokamaks by coupling the B2-EIRENE and DSMC method.
• The results include pressure, temperature, bulk velocity and particle fluxes in the subdivertor.
• Gas recirculation effect towards the plasma chamber through the vertical targets is found.
• Comparison between DSMC and the ITERVAC code reveals a very good agreement.

This paper presents a new innovative scientific and engineering approach for describing sub-divertor gas flows of fusion devices by coupling the B2-EIRENE (SOLPS) code and the Direct Simulation Monte Carlo (DSMC) method. The present study exemplifies this with a computational investigation of neutral gas flow in the ITER's sub-divertor region. The numerical results include the flow fields and contours of the overall quantities of practical interest such as the pressure, the temperature and the bulk velocity assuming helium as model gas. Moreover, the study unravels the gas recirculation effect located behind the vertical targets, viz. neutral particles flowing towards the plasma chamber. Comparison between calculations performed by the DSMC method and the ITERVAC code reveals a very good agreement along the main sub-divertor ducts.