Comparison of the Improved GTNEUT with Monte Carlo for DIII-D Neutrals Experiments

The Transmission-Escape-Probability method [1] has been developed and implemented in the GTNEUT code [2] as an accurate and efficient calculation of 2D neutral particle transport in complex plasma edge geometry. Three extensions of TEP methodology-anisotropic angular fluxes to calculate transmission coefficients [3], intra-region diffusion theory directional refinement of escape probabilities [4], and calculation of the local neutral energy distribution [4]-have been developed which significantly improve the range of validity. Detail comparisons of the improved GTNEUT with Monte Carlo methods for neutral measurements in DIII-D L- and H-mode shots have been made. Agreement of GTNEUT with Monte Carlo and the data has improved significantly.\par \vspace{0.5em} \noindent [1] W.M. Stacey and J. Mandrekas, Nucl. Fusion $\bf {34}$, 1385 (1994).\par \noindent [2] J. Mandrekas, Comput. Physics Comm, $\bf {161}$, 36 (2004).\par \noindent [3] D. Zhang, J. Mandrekas and W.M. Stacey, Contributions to Plasma Phys. $\bf {44}$, 45 (2004).\par \noindent [4] D. Zhang, ``Neutral Particle Transport in Plasma Edge Using Transmission/Escape Probability (TEP) Method," PhD Thesis, Georgia Institute of Technology (2005).