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2008
Core localized Alfvén eigenmodes in DIII-D [J. L. Luxon, Nucl. Fusion 42 , 614 (2002)] and Joint European Torus JET [P. H. Rebut and B. E. Keen, Fusion Technol. 11 , 13 (1987)] plasmas are driven by deuterium neutral beam ions traveling well below the Alfvén speed. Modes are observed in reverse magnetic shear discharges with deuterium ion velocit…
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2008
A simple formula for predicting the width of a saturated island, formed as a consequence of tearing perturbation of linear force-free fields in cylindrical geometry, is derived. The formula makes it possible to calculate the saturated island width in terms of the values of parameters characterizing the initial force-free equilibrium and can be appl…
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2008
A perturbative three-dimensional analysis is presented of Alfvén waves in a magnetic X-point configuration with a strong longitudinal guide field. The waves are assumed to propagate in the direction of the X-line, and both the plasma beta and equilibrium plasma current are taken to be zero. This provides a simple model of Alfvén wave propagation …
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2008
The tokamak plasma boundary, which is typically identified with the area of open field lines known as the scrape-off layer (SOL), determines the degree of plasmawall interaction. SOL physics, much of which is concerned with the exhaust (removal) of particles and energy from the plasma, has been one of the major topics investigated on JET during the…
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2008
Edge Localised Modes (ELMs) are periodic disturbances of the plasma periphery occurring in tokamaks with an H-mode edge transport barrier. As a result, a fraction of the plasma energy present in the confined hot edge plasma is transferred to the open field lines in the divertor region, ultimately appearing at the divertor target plates. These event…
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2008
In this paper we model (111) self-interstitial defects, or crowdions, using an extended version of the analytical Frenkel-Kontorova model. We use a more general potential than the traditional sinusoidal one, and find that it can better describe the lattice potentials experienced by crowdions in the body-centred-cubic transition metals, as calculate…
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2008
The need to understand and control the dynamics of reactor grade fusion plasmas requires the analysis of increasing amounts of data, which at JET can reach easily the level of several GBytes per shot. Therefore a series of new approaches are being pursued to store the data and to retrieve the required information. They range from loss less data com…
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2007
JET has made a strong contribution to the understanding of stability issues for the tokamak. An overview of its main achievements is presented, with emphasis on the latest progress in resolving the key issues for ITER. In particular, we conclude that control or avoidance strategies for neoclassical tearing modes (NTMs) will be necessary for good pe…
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2007
Achieving the economically viable release of energy by the fusion process has proved a major scientific and technological challenge. The nuclear reactions involved in the fusion process are well understood, but the interaction of the neutrons with the materials surrounding the plasma is an area of current research. The neutrons have energies larger…
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2007
Principal techniques and trends in the validation and analysis of data in magnetic fusion research are described and examples of applications are given. Wellestablished methods to obtain key physical quantities are outlined, as well as newer techniques employing integrated analysis of multiple diagnostics to improve quality and extract additional i…
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