(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, 2009-10-15)
Stacey, Weston M.; Groebner, Rich J.
A procedure is described for evaluating particle pinches to be used in interpreting particle diffusion coefficients from measured density and temperature profiles in the edge pedestal of tokamak plasmas. Application to the interpretation of two DIII-D [ J. Luxon, Nucl. Fusion 42, 614 (2002) ]. discharges yields new information about particle pinches and particle diffusion coefficient profiles in the edge pedestal.
(Georgia Institute of Technology, 2008-01-25)
Stacey, Weston M.; Groebner, Rich J.
A novel methodology for inferring experimental toroidal angular momentum transfer rates from measured toroidal rotation velocities and other measured quantities has been developed and applied
to analyze rotation measurements in the DIII-D J. Luxon, Nucl. Fusion 42, 6149 2002 edge pedestal. The experimentally inferred values have been compared with predictions based on atomic physics processes and on neoclassical toroidal viscosity. The poloidal rotation velocities have been
calculated from poloidal momentum balance using neoclassical parallel viscosity and a novel retention of all terms in the poloidal momentum balance, and compared with measured values in the DIII-D edge pedestal.
(Georgia Institute of Technology, 2007-12-11)
Stacey, Weston M.; Groebner, Rich J.
Using temperature and density profiles averaged over the same subinterval of several successive inter-edge-localized-mode (ELM) periods, the ion and electron thermal diffusivities in the edge pedestal were inferred between ELMs for two DIII-D [ J. Luxon, Nucl. Fusion 42, 614 (2002) ] discharges. The inference procedure took into account the effects of plasma reheating and density buildup between ELMs, radiation and atomic physics cooling, neutral beam heating and ion-electron equilibration, and recycling neutral and beam ionization particle sources in determining the conductive heat flux profiles used to infer the thermal diffusivities in the edge pedestal. Comparison of the inferred thermal diffusivities with theoretical formulas based on various transport mechanisms was inconclusive insofar as identifying likely transport mechanisms.
(Georgia Institute of Technology, 2007-01-04)
Stacey, Weston M.; Groebner, Rich J.
The ion and electron thermal diffusivities have been inferred from measured density and temperature profiles in the edge of a DIII-D [ J. Luxon, Nucl. Fusion 42, 614 (2002) ] discharge with a low confinement (L-mode) stage followed by a high confinement (H-mode) stage free of edge localized modes. Conductive heat flux profiles used to construct the inferred thermal diffusivities were calculated taking into account heat convection, radiation, atomic physics effects of recycling neutrals, ion-electron equilibration, and neutral beam heating. The inferred thermal diffusivities were compared with theoretical predictions.