Monte Carlo Simulation for Particle Behavior of Recycling Neutrals in a Tokamak Diverter Region

  • Published : 1997.12.01

Abstract

The steady-state behavior of recycling neutral atoms in a tokamak edge region has been analyzed through a two-dimensional Monte Carlo simulation. A particle tracking algorithm used in earlier research on the neutral particle transport is applied to this Monte Carlo simulation in order to perform more accurate calculations with the EDGETRAN code which was previously developed for a two-dimensional edge plasma transport in the authors' laboratory. The physical model of neutral recycling includes charge-exchange and ionization interactions between plasmas and neutral atoms. The reflection processes of incident particles on the device wall are described by empirical formulas. Calculations for density, energy, and velocity distributions of neutral deuterium-tritium atoms have been carried out for a medium-sized tokamak with a double-null configuration based on the KT-2 conceptual design. The input plasma parameters such as plasma density, ion and electron temperatures, and ion fluid velocity are provided from the EDGETRAN calculations. As a result of the present numerical analysis, it is noticed that a significant drop of the neutral atom density appears in the region of high plasma density and that the similar distribution of neutral energy to that of plasma ions is present as frequently reported in other studies. Relations between edge plasma conditions and the neutral recycling behavior are discussed from the numerical results obtained herein.

Keywords

References

  1. Fusion Technol. v.11 Neutral Particle Kinetics in Fusion Devices M. Tendler;D.B. Heifetz
  2. Nucl. Fusion v.30 Plasma Boundary Phenomena in Tokamak P.C. Stangeby;G.M. McCracken
  3. in Physics of Plasma-Wall Interactions in Controlled Fusion, edited by D.E. Post and R. Behrisch Neutral Particle Transport D.B. Heifetz
  4. Nucl. Fusion v.33 Can Detached Divertor Plasmas Be Explained As Self-sustained Gas Target? P.C. Stangeby
  5. Phys. Plasma v.2 Thermal Bifurcation of Scarpe-off Layer Plasma and Divertor Detachment S.I. Krasheninnikov;P.J. Catto;P. Helander;D.J. Sigmar;T.K. Sovoleva
  6. Nucl. Fusion v.34 Estimation of the Maximum Divertor Radiative Fractions in the Presence of a Neutral Cushion K. Borass;G. Janeschitz
  7. Nucl. Fusion v.18 J.G. Gilligan;S.L. Gralnick;W.G. Price Jr.;T. Kammash
  8. J. Comp. Phys. v.34 SPUDNUT: A Transport Code for Neutral Atoms in Plasma K. Audenaerde;G.A. Emmert;M. Gordinier
  9. J. Comp. Phys. v.40 ANTIC: A Code for Calculation of Neutral Transport in Cylindrical Plasma S.J. Tamor
  10. J. Comp. Phys v.28 A Monte Carlo Algorithm for Calculating Neutral Gas Transport in Cylindrical Plasmas M.H. Hughes;D.E. Post
  11. Comput. Phys. Comm. v.29 SEURAT: A Monte Carlo Algorithm for Calculating Neutral Gas Transport in Non-circular Axisymmetric Toroidal Plasmas D.B. Heifetz;D.E. Post
  12. in Data Compendium for Plasma-Surface Interactions Reflection of Light Ions From Solid W. Eckstein;H. Verbeek
  13. Conceptual Definition of KT-2, KAERI/TR-472/94, Korea Atomic Energy Research Institute Report KAERI
  14. Ph.D. Dissertation Edge Plasma Transport Modeling for Limited and Diverted Tokamaks with Self-consistent Poloidal Drifts K. Im
  15. J. Korean Phys. Soc. v.29 Numerical Modeling of Edge Plasmas in Tokamaks with Poloidal Limiters K. Im;D.K. Kim;S.H. Hong
  16. in Proceedings of the 3rd International Workshop on Plasma Edge Theory in Fusion Devices, Bad Honnef, June 22-24, 1992, edited by P. Bachmann and D.F. Duchs, P. 450 Extension of B2 for the Simulation of ASDEX-Upgrade Scrape-off Layer Plasmas R. Schneider;B. Braams.;D. Reiter;H.P. Zehrfeld;J. Neuhauser;M. Baelmans;H. Kastelewicz;R. Wunderlich