Development in the DIII-D Tokamak of Advanced Operating Scenarios and Associated Control Techniques for ITER
M. Wade, (E. Schuster), et al. (Collaboration Paper)
IAEA Fusion Energy Conference
Chengdu, China, October 16-21, 2006
Abstract
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Significant progress has been made on the DIII-D tokamak in the
capability to control key plasma features and using such control to
expand the operational limits of stationary and steady-state tokamak
operation. Recent experiments have demonstrated the capability to
suppress the key plasma instabilities of concern for ITER, including
edge localized modes, neoclassical tearing modes, and resistive wall
modes. In addition, the ability to regulate the rotation and current
density profiles through feedback control has been demonstrated. The
use of these control techniques has allowed an expansion of the
envelope of viable, stationary tokamak operation, highlighted by the
demonstration of sustained (~2 s) operation of beta_N ~ 4 (50% above
the no-wall stability limit) as well as fully noninductive operation
with beta ~ 3.5%. This development is supported by a vigorous basic
physics program, which has provided new insights into turbulence
dynamics over a large range in spatial scales, new measurements of
the structure of fast-ion instabilities and their effect on the fast
ion population, and important information on the transport of carbon
and associated tritium co-deposition on plasma facing surfaces.