(Georgia Institute of Technology, 2006)
Stacey, Weston M.; Zhang, Dingkang; Mandrekas, John
Higher order approximations, which take into account the effects of angular anisotropy, spatial non-uniformity and energy dependence of the distribution of neutral particles, have been developed and implemented to extend the range of validity of the Transmission and Escape Probabilities (TEP) method for the calculation of neutral particle transport in plasmas. Comparisons with Monte Carlo calculations of model test problems and DIII-D L- and H- mode discharges show that these new extensions significantly improve the accuracy and extend the range of validity of the TEP methodology.
(Georgia Institute of Technology, 2006)
Stacey, Weston M.; Johnson, R. W.; Mandrekas, John
Momentum and particle balance and neoclassical viscosity were applied to
calculate the radial profile of toroidal rotation velocity in several DIII-D [J. Luxon, Nucl.
Fusion, 42, 614 (2002)] discharges in a variety of energy confinement regimes (Lowmode,
Low-mode with Internal Transport Barrier, High-mode, and High-mode with
Quiescent Double Barrier). Calculated toroidal rotation velocities generally were found
to (over-) predict measured values to well within a factor of 2.
(Georgia Institute of Technology, 2005-10)
Stacey, Weston M.; Johnson, R. W.; Mandrekas, John
Momentum and particle balance and neoclassical viscosity were applied to calculate the radial
profile of toroidal rotation in several DIII-D [J. Luxon, Nucl. Fusion, 42, 614 (2002)] discharges in a
variety of energy confinement regimes (Low-mode, Low-mode with Internal Transport Barrier, Highmode,
and High-mode with Quiescent Double Barrier). Calculated toroidal rotation velocities were found
to over-predict measured values most in the center—by factors of 1.5 to 3--with the over-prediction
generally decreasing with increasing radius, for the L, H and ITB mode shots, but the single impurity
species approximation could not properly model the multiple Ni and Cu charge states in the QDB shots.
(Georgia Institute of Technology, 2005-10)
Zhang, Dingkang; Mandrekas, John; Stacey, Weston M.
Extensions of the 2D Transmission and Escape Probability neutral particle transport method in treating
the spatial non-uniformity of collision sources and neutral energy effects are presented. These extensions
have been tested by benchmarks against Monte Carlo calculations for specially designed models and for
realistic DIII-D discharges. The comparisons indicate these extensions improve accuracy of the TEP
method.