DIII-D Contributions Toward the Scientific Basis for Sustained Burning Plasmas
C.M. Greenfield, (E. Schuster), et al. (Collaboration Paper)
IAEA Fusion Energy Conference
Daejon, Korea, 11-16 October 2010
Abstract
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DIII-D is making significant contributions to a scientific basis for
sustained burning plasma opera- tion. These include explorations of
increasingly reactor relevant scenarios, studies of key issues for
projecting performance, development of techniques for handling heat
and particle efflux, and assessment of key issues for the ITER Research
Plan. Steady-state scenarios are generated and maintained for a duration
limited by hard- ware, using tailoring of the early evolution and
precise targeting of external current drive. Joint DIII-D/JET \rho* scans
in the hybrid regime imply Bohm-like confinement scaling. Startup and
shutdown techniques were devel- oped for the restrictive environment of
future devices while retaining compatibility with advanced scenarios.
Toward the goal of a fully predictive capability, the DIII-D program
emphasizes validation of physics-based models, facilitated by a number
of new and upgraded diagnostics. Specific areas include transport,
rotation, energetic particles, and the H-mode pedestal, but this
approach permeates the entire research program. Concerns for heat and
particle efflux in future devices are addressed through studies of ELM
control, disruption avoidance and mitigation, and hydrogenic retention
in DIII-D’s carbon wall. DIII-D continues to respond to specific needs
for ITER. Recent studies have compared H-mode access in several
different ion species, identifying not only isotopic, but density,
rotation, and geometrical dependencies that may guide access to H-mode
during ITER’s non-activated early operation. DIII-D used an insertable
module to simulate the magnetic perturbations intro- duced by one of
ITER’s three Test Blanket Module sets, demonstrating that little impact
on performance is seen at ITER equivalent levels of magnetic perturbation.