David Gates

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Citation Humphreys, D.A. et al. "Experimental vertical stability studies for ITER performance and design guidance. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Abstract. Operating experimental devices have provided key inputs to the design process for ITER axisymmetric control. In(More)
Experiments in NSTX have now demonstrated the coupling of toroidal plasmas produced by the technique of Coaxial Helicity Injection (CHI) to inductive sustainment and ramp-up of the toroidal plasma current. In these discharges, the central Ohmic transformer was used to apply an inductive loop voltage to discharges with a toroidal current of about 100 kA(More)
In this paper we summarize the results of the modelling, analyses and assessment of the ITER Vertical Stabilization (VS) system design carried out in the last two years by the ITER IO and Domestic Agencies as well as its possible improvements: these include the use of an additional VS system connecting some of the Central Solenoid coils, a power supply(More)
Regulation in time of the toroidal current profile is one of the main challenges toward the realization of the next-step operational goals for the National Spherical Tokamak eXperiment - Upgrade (NSTX-U). In this work, a nonlinear, control-oriented, physics-based model describing the temporal evolution of the current profile is first obtained by combining(More)
New shape control implementations and dynamics studies on the National Spherical Torus eXperiment (NSTX) (Ono et al 2000 Nucl. Fusion 40 557–61) are summarized. In particular, strike point position, X-point height and squareness control, and two new system-identification methods/control-tuning algorithms were put into operation. The PID controller for the(More)
The plasma material interface in Demo will be more challenging than that in ITER, due to requirements for approximately four times higher heat flux from the plasma and approximately five times higher average duty factor. The scientific and technological solutions employed in ITER may not extrapolate to Demo. The key questions to be resolved for Demo and the(More)
The mission of the National Spherical Torus Experiment (NSTX) is the demonstration of the physics basis required to extrapolate to the next steps for the spherical torus (ST), such as a plasma facing component test facility (NHTX) or an ST based component test facility (ST-CTF), and to support ITER. Key issues for the ST are transport, and steady state high(More)
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