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2009
Experiments have been performed on MAST using both external (n=1,2) and internal (n=3) resonant magnetic perturbation coils. ELM suppression has not been achieved even though vacuum modelling shows that either set of coils can produce a region for which the Chirikov parameter is greater than 1 wider than that required to produce ELM suppression in …
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2009
Neutral beam current drive NBCD experiments in DIII-D using vertically shifted plasmas to move the current drive away from the axis have clearly demonstrated robust off-axis NBCD. Time-dependent measurements of magnetic field pitch angles by the motional Stark effect diagnostic are used to obtain the evolution of the poloidal magnetic flux, which i…
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2009
Neo-classical tokamak plasma theory predicts poloidal rotation driven by the temperature gradient of order ~ few km/s. In conventional aspect ratio tokamak plasmas, e.g. on JET and DIII-D, poloidal velocities considerably in excess of the neo-classical values have been measured, particularly in the presence of internal transport barriers (ITBs), by…
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2009
A set of simulation/interpretation tools based on transmission line theory and on the RF model developed by M. Vrancken [2] has been developed to study the ITER-like Antenna (ILA) at JET. For given tuning element settings, the unique solution of the equations governing the ILA circuit requires solving a system of coupled linear equations relating t…
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2009
The penetration of the magnetic field in a rotating inhomogeneous plasma is investigated with direct numerical simulations. The main focus of this work is to test the linear, singular-layer models when diamagnetic and finite Larmor radius effects are included. Our results confirm the existing analytical prediction when the plasma velocity at the re…
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2009
Analytical theory and two different magnetohydrodynamical stability codes are used in a study of the effects of toroidal plasma rotation on the stability of the ideal, internal kink mode in tokamaks. The focus of the paper is on the role that the centrifugal effects on the plasma equilibrium play for the stability of this mode, and results from one…
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2009
A self-consistent, rigorous approach is proposed to study the synergistic effects of plasma flow, drift kinetic resonances and three-dimensional conducting structures on the resistive wall mode. This approach is based on coupling between the hybrid MHD-kinetic computation and the 3D electromagnetic eddy current computation via a specific boundary c…
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2009
A Sub-Harmonic Arc Detection (SHAD) system has been installed on the transmission lines feeding the JET ICRF ITER-like-Antenna (ILA). Along with the commissioning of SHAD, extensive measurements of the RF field in the transmission lines were carried-out using fast sampling (125 Mb/s) oscilloscopes. The system is described, and the SHAD ability to d…
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2009
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2009
Impurity ions with sufficiently high mass in toroidally-rotating tokamak plasmas are deeply trapped by a centrifugal potential well in the outer plasma midplane, with a bounce period that is shorter than both the bounce period of magnetically-trapped ions and the collision time. As a result trace impurity ions can undergo collisional transport at a…
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