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2013
When using Ion Cyclotron Range of Frequency (ICRF) heating, enhanced heat-fluxes are commonly observed on some plasma facing components close to the antennas. Experiments have recently been carried out on JET with the new ITER-Like-Wall (ILW) to characterize the heat flux to the JET ICRF antennas. Using Infra-Red thermography and thermal models of …
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2013
A load-tolerant External Conjugate-T (ECT) impedance matching system for two A2 Ion Cyclotron Resonance Heating (ICRH) antennas has been successfully put into operation at JET. The system allows continuous injection of the RF power into plasma in the presence of strong antenna loading perturbations caused by Edge Localized Modes (ELMs). Reliable EC…
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2013
This paper will discuss simulations of the full ionization process (i.e. plasma burn-through), fundamental to creating high temperature plasma. By means of an applied electric field, the gas is partially ionized by the electron avalanche process. In order for the electron temperature to increase, the remaining neutrals need to be fully ionized in t…
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2013
Recent experiments on in situ high-energy self-ion irradiation of tungsten (W) show the occurrence of unusual cascade damage effects resulting from single-ion impacts, shedding light on the nature of radiation damage expected in the tungsten components of a fusion reactor. In this paper, we investigate the dynamics of defect production in 150 keV c…
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2013
The pedestal profile measurements in high triangularity JET plasmas show that with low fuelling the pedestal width decreases during the ELM cycle and with high fuelling it stays constant. In the low fuelling case the pedestal pressure gradient keeps increasing until the ELM crash and in the high fuelling case it initially increases then saturates d…
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2013
The kinetic effect of trapped energetic particles (EPs), arising from perpendicular neutral beam injection, on the stable low-n peeling modes in tokamak plasmas is investigated, through numerical solution of the mode’s dispersion relation derived from an energy principle. A resistive-wall peeling mode with m/n = 6/1, with m and n being the poloid…
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2013
Compressible ideal magnetohydrodynamics is formulated in terms of the time evolution of potential vorticity and magnetic flux per unit mass using a compact Lie bracket notation. It is demonstrated that this simplifies analytic solution in at least one very important situation relevant to magnetic fusion experiments. Potentially important implicatio…
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2013
The distribution of particles and power to plasma-facing components is of key importance in the design of next-generation fusion devices. Power and particle decay lengths have been measured in a number of MAST L-mode and H-mode discharges in order to determine their parametric dependencies, by fitting power and particle flux profiles measured by di…
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2013
Previous experiments on MAST and other tokamaks have indicated that the level of fast ion redistribution can exceed that expected from classical diffusion and that this level increases with beam power. In this paper we present a quantification of this effect in MAST plasmas using a recently commissioned scanning neutron camera. The observed fast io…
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2013
Many models for anomalous transport consider the turbulent E × B transport arising from electrostatic micro-instabilities. In this paper we investigate whether the perturbed magnetic field that is associated with such instabilities at small but finite values of ß can lead to significant stochastic magnetic field transport. Using the tearing parit…
Showing 1741 - 1750 of 2526 UKAEA Paper Results