(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.
(Georgia Institute of Technology, 2005-04)
Stacey, Weston M.; Groebner, Rich J.
A calculation of edge density and temperature profiles based on "classical"
physics - particle, momentum and energy balance, heat conduction closure relations,
neutral particle transport - yielded a pedestal structure that is qualitatively and
quantitatively similar to that found experimentally in five DIII-D [J. Luxon, Nucl. Fusion,42, 614 (2002)] discharges, when experimental radial electric field and rotation profiles
and experimentally inferred heat transport coefficients were used. The principal cause of
the density pedestal was a peaking of the inward pinch velocity just inside the separatrix
caused by the negative well in the experimental electric field, and the secondary cause
was a peaking of the radial particle flux caused by the ionization of incoming neutrals.
There is some evidence that this peaking of the radial particle flux just inside the
separatrix may also be responsible in part for the negative electric field in that location.
(Georgia Institute of Technology, 2005)
Stacey, Weston M.; Mandrekas, John; Hoffman, E. A. (Elisha Albright)
The principal results of a series of design
scoping studies of sub-critical fast transmutation
reactors (based on the nuclear and processing
technology being developed in the USDoE
Generation IV, Advanced Fuel Cycle and Next
Generation Nuclear Plant programs) coupled with a
tokamak fusion neutron source (based on the ITER
design basis physics and technology) are presented.