(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
(Georgia Institute of Technology, 2005-10)
Stacey, Weston M.; Friis, Zachary Ward; Petrie, Thomas W.; Leonard, Anthony W.
The common observation that the onset of a core MARFE (Multifaceted Asymmetric Radiation From Edge) is followed immediately by a H-L (High-to-Low) confinement mode transition in DIII-D [J.
Luxon, Nucl. Fusion, 42, 614 (2002)] was investigated by comparing a theoretical prediction of the threshold non-radiative power across the separatrix needed to maintain H-mode with an experimental
determination of the non-radiative power flowing across the separatrix. It was found that in three shots
with continuous gas fueling the increased neutral influx associated with the MARFE formation caused a
sharp increase in the predicted threshold non-radiative power crossing the separatrix that was required for
the plasma to remain in H-mode to a value comparable to the experimental power crossing the separatrix.