(Georgia Institute of Technology, 2011-10-14)
Stacey, Weston M.
Calculation models are presented for treating ion orbit loss effects in interpretive fluid transport calculations for the tokamak edge pedestal. Both standard ion orbit loss of particles following trapped or passing orbits across the separatrix and the X-loss of particles that are poloidally trapped in a narrow null-Bθ region extending inward from the X-point, where they gradB and curvature drift outward, are considered. Calculations are presented for a representative DIII-D [J. Luxon, Nucl. Fusion 42, 614 (2002)] shot which indicate that ion orbit loss effects are significant and should be taken into account in calculations of present and future experiments.
(Georgia Institute of Technology, 2010-11-22)
Stacey, Weston M.; Groebner, Rich J.
The various terms in the radial force balance in the edge plasma are evaluated using experimental data from the low (L) and high (H) confinement phase of a DIII-D [J. Luxon, Nucl. Fusion 42, 614 (2002)] discharge in order to investigate the differences in the radial force balance among the several electromagnetic and pressure gradient forces in L-mode and H-mode. The roles of cross-field toroidal momentum transport and of a radial pinch velocity in determining different radial particle fluxes in L-mode and H-mode are elucidated
(Georgia Institute of Technology, 2010-05-19)
Stacey, Weston M.
The edge density profile is calculated from the continuity and momentum balance equations, using experimental electric field and rotation velocities and a calculated recycling neutral source, to
evaluate the relative importance of these quantities in determining the observed structure of the edge density profile in a DIII-D _J. Luxon, Nucl. Fusion 42, 614 _2002__ high-confinement mode discharge.
(Georgia Institute of Technology, 2010-05-17)
Stacey, Weston M.
A formalism is presented for evaluating the effect of plasma rotation, via viscous heating, on the interpretation of thermal conductivities from measured temperature and density gradients in the edge pedestal. An application to a H-mode DIII-D [ J. Luxon, Nucl. Fusion 42, 614 (2002) ] discharge indicates that the effect could be significant.
(Georgia Institute of Technology, 2010-02-23)
Friis, Zachary Ward; Stacey, Weston M.; Leonard, Anthony W.; Rensink, M. E.
A detailed analysis of neutral atom recycling and pedestal fueling in a DIII-D _J. Luxon, Nucl.
Fusion 42, 614 _2002__ high-confinement mode discharge is presented. Experimental data and
two-dimensional _2D_ edge plasma fluid code calculations are employed to provide ion wall
recycling and recombination neutral sources and background edge plasma parameters for a 2D edge
neutral code calculation of detailed neutral density, ionization, and charge-exchange distributions
throughout the edge pedestal, scrape-off layer and surrounding halo region, divertor, and private flux
regions. The effectiveness of the different neutral sources for fueling the confined plasma is
evaluated