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CCFE-PR(16)102016
The magnetic perturbations produced by the resonant magnetic perturbation (RMP) coils will be rotated in ITER so that the spiral patterns due to strike point splitting which are locked to the RMP also rotate. This is to ensure even power deposition on the divertor plates. VMEC equilibria are calculated for different phases of the RMP rotation. It i…
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CCFE-PR(16)802016
The Joint European Torus (JET) high resolution Thomson scattering (HRTS) system measures radial electron temperature and density profiles. One of the key capabilities of this diagnostic is measuring the steep pressure gradient, termed the pedestal, at the edge of JET plasmas. The pedestal is susceptible to limiting instabilities, such as Edge Local…
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CCFE-PR(15)432015
A set of flux tube gyrokinetic equations that includes the effect of the spatial variation of the density, temperature and rotation gradients on the turbulence is derived. This new set of equations uses periodic boundary conditions. In the limit l?/L « 1, where l? is the characteristic perpendicular length of turbulent structures and L is the char…
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CCFE-PR(15)412015
Self-consistent equations for intrinsic rotation in tokamaks with small poloidal magnetic field Bp compared to the total magnetic field B are derived. The model gives the momentum redistribution due to turbulence, collisional transport and energy injection. Intrinsic rotation is determined by the balance between the momentum redistribution and the …
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CCFE-PR(15)082015
Tokamak plasmas rotate even without external injection of momentum. A Doppler backscattering system installed at MAST has allowed this intrinsic rotation to be studied in Ohmic L-mode and Hmode plasmas, including the first observation of intrinsic rotation reversals in a spherical tokamak. Experimental results are compared to a novel 1D model, whic…
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2015
Nanoindentation has been performed on tungsten, unimplanted and helium-implanted to $ 600 appm, at temperatures up to 750 1 C. The hardening effect of the damage was 0.90 GPa at 50 1 C, but is negligible above 450 1 C. The hardness value at a given temperature did not change on re-testing after heating to 750 1 C. This suggests that the helium is t…
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CCFE-PR(15)192015
Rotating collectors are used in JET to provide time-resolved measurements of erosion and redeposition of vessel materials. The silicon collecting disks rotate behind an aperture, driven by pulsing of the toroidal magnetic field, with the deposits analysed ex-situ by Nuclear Reaction Analysis. The angular dependence of deposition is mapped to discha…
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2014
A new coherence imaging Doppler spectroscopy diagnostic has been deployed on the UK’s Mega Amp Spherical Tokamak for scrape-off-layer and divertor impurity flow measurements. The system has successfully obtained 2D images of C III, C II, and He II line-of-sight flows, in both the lower divertor and main scrape-off-layer. Flow imaging has been obt…
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2014
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2014
Tokamak plasmas rotate even without any external injection of momentum. A Doppler backscattering system installed at MAST has allowed this intrinsic rotation to be studied in Ohmic L-mode and H-mode plasmas, including the first observation of intrinsic rotation reversals in a spherical tokamak. Experimental results are compared to a novel 1D model,…
Showing 31 - 40 of 61 UKAEA Paper Results