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2009
The commissioning of the ITER-Like ICRF Antenna (ILA) [1] on JET plasmas from May 2008 to April 2009 in various conditions (33, 42 and 47 MHz, L- and H-mode, antenna strap-plasma separatrix distances of ~9 to 17 cm) has provided relevant information for future antenna design and operation. The maximum power density achieved was 6.2 MW/m2 in L-mode …
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2009
‘Advanced tokamak’ (AT) scenarios were developed with the aim of reaching tokamak steady-state operation. They are designed to optimise the self-generated current, whilst also reaching sufficiently high plasma pressure to achieve optimal fusion reaction rates. AT scenarios exhibit non-monotonic to flat safety factor profiles (q, a measure of th…
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2009
One of the main operational aims of the MAST experiment [1] and the proposed MAST upgrade is to investigate possible mechanisms to control the q-profile and drive off-axis current. Experiments were carried out to determine the extent to which the q-profile may be modified using two different approaches, transient and steady-state. Transient effects…
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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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