Title:
Investigation of edge pedestal structure in DIII-D (DoE Grant ER54538)
Investigation of edge pedestal structure in DIII-D (DoE Grant ER54538)
Author(s)
Stacey, Weston M.
Groebner, Rich J.
Groebner, Rich J.
Advisor(s)
Editor(s)
Collections
Supplementary to
Permanent Link
Abstract
A calculation based on the requirements of particle, momentum and energy conservation,
conductive heat transport and atomic physics resulting from a recycling and fueling neutral influx was
employed to investigate the experimental density, temperature, rotation velocities and radial electric field
profiles in the edge of three DIII-D [J. Luxon, Nucl. Fusion, 42, 614 (2002)] high-mode plasmas. The
calculation indicated that the cause of the pedestal structure in the density was a momentum balance
requirement for a steep negative pressure gradient to balance the forces associated with an edge peaking
in the inward pinch velocity (caused by the observed edge peaking in the radial electric field and rotation
velocity profiles) and, to a lesser extent, in the outward radial particle flux (caused by the ionization of
recycling neutrals). Thermal and angular momentum transport coefficients were inferred from
experiment and compared with theoretical predictions, indicating that thermal transport coefficients were
of the magnitude predicted by neoclassical and ion-temperature-gradient theories (ions) and electrontemperature-
gradient theory (electrons), but that neoclassical gyroviscous theory plus atomic physics
effects combined were not sufficient to explain the inferred angular momentum transfer rate throughout
the edge region.
Sponsor
DoE Grant ER54538
Date Issued
2005-10
Extent
444009 bytes
Resource Type
Text
Resource Subtype
Pre-print