Transport of deuterium - tritium neutrals in ITER divertor M. Z. Tokar and V.Kotov Plasma and neutral gas in ITER divertor will be mixed of deuterium and tritium → Tritium is radioactive and its content has to be minimized → This can be achieved by tuning plasma fueling with gas puffing and pellet injection [1] → Divertor plasma transparency for neutrals is of importance by searching for such conditions → Two-dimensional transport modeling of d-t neutral mixture is necessary Motivation Divertor geometry under consideration Comparison of numerical and analytical results SOL plasma transparency for atoms Fluid transport equations for isotope atoms Boundary conditions Outflow of atoms into private flux region: Analytical consideration for homogeneous plasma parameters and  << 1 n e = 2  m -3, T e = 5eV, sin  = 0.1 Conclusions Input plasma parameter profiles from SOLPS4.3 [3] Private flux region Target plate Wall y x  ymym SOL  Recycling of d-t atoms generated by recombination of deuterons, tritons and electrons on target plates Atom ionization ( k ion ) and volume recombination, radiative and 3-body, of ions and electrons ( k rec ) Refueling of SOL plasma with isotope atoms through interface with private flux region due to finite pumping rate Charge-exchange of atoms and ions of the same kind ( k cx ~m -1/3 [2]) Cross-charge-exchange of deuterium atoms with tritons and tritium atoms with deuterons ( k * cx ) Physical processes in the model Particle continuity for atom densities n l=2,3 : Atom disintegration frequency: Atom source density:  Diffusion-like equations for atom pressure P l = n l T : Atom “diffusivity”: Momentum source density: Recycling of atoms at target plate ( y = x cot  ) : Momentum transfer for atom flux densities j l=2,3 : Recycling of atoms at wall ( x =  ) : Finite probability  l for atoms to return from private flux region ( x = 0 ) : Attached divertor: Computed atom density profiles Attached ITER divertor: P SOL = 80 MW, P PFR = 2 Pa Detached ITER divertor: P SOL = 120 MW, P PFR = 13 Pa Detached divertor: Outflow of ions to target plate: SOL transparencies: Attached plasma Detached plasma  l are of importance to determine the plasma component densities near the target pates and impose boundary conditions for particle transport equations in SOL and in confined plasma region Equations for atom pressure variation along the normal to the target plate, s : For new variables: Equations are decoupled if: numericalanalytical Transport of deuterium and tritium atoms is modeled in two-dimensional geometry by taking into account the cross-charge-exchange between ions and neutral particles of different isotopes Reasonable agreement with Monte Carlo code EIRENE for transport of deuterium neutrals For d-t mixture present computations predict a significantly smaller transparency of SOL plasma for tritium atoms than for deuterium ones Predictions of numerical calculations are verified by comparing with analytical model [1] Tokar M. Z. and Moradi S Nucl. Fusion [2] Potters J.H.H.M. and Goedheer W.J Nucl. Fusion [3] Kukushkin A. S. et al 2009 Nucl. Fusion References