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UKAEA-CCFE-PR(18)402018
Experimental evidence is presented of a discrepancy between the predicted and measured D-D fusion products rates on MAST. Both the neutron and proton production rates, measured independently with a neutron camera and charged fusion product detector array, are approximately 40 % lower than those predicted by TRANSP/NUBEAM codes. This deficit is scen…
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UKAEA-CCFE-PR(18)392018
Tungsten has long been the favoured armour material for plasma facing high heat flux components proposed for future fusion reactors, but studies examining the use of tungsten or other refractory metals in the underlying cooled structures have historically excluded them, leaving current concepts heavily dependent on copper alloys such as copper chro…
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UKAEA-CCFE-PR(18)342018
Tangentially viewing fast camera footage of the low-field side snowflake minus divertor in TCV is analysed across a four point scan in which the proximity of the two X-points is varied systematically. The apparent flow observed in the post-processed movie shows two distinct regions of the camera frame exhibiting differing flow patterns. One flow in…
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UKAEA-CCFE-PR(18)232018
Ray-tracing techniques are applied to bolometry, a diagnostic particularly sensitive to machine geometry due to the effect of volume sampling. Sightlines from the ASDEX-Upgrade bolometer foils were ray-traced with a path tracing algorithm, where the optical path is represented by a statistical bundle of ray paths connecting the foil surface with th…
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UKAEA-CCFE-PR(18)62018
Velocity-space tomography provides a way of diagnosing fast ions in a fusion plasma by combining measurements from multiple instruments. We use a toroidally viewing and a vertically viewing fast-ion D-alpha (FIDA) diagnostic installed on the spherical tokamak MAST (before the upgrade) to perform velocity-space tomography of the fast-ion distributio…
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CCFE-PR(17)702017
It has been previously demonstrated in (Li et al 2016 Nuclear Fusion 56 126007) that the optimum upper/lower coil phase shift ΔΦopt for alignment of RMP coils for ELM mitigation depends sensitively on q95, and other equilibrium plasma parameters. Therefore, ΔΦopt is expected to vary widely during the current ramp …
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CCFE-PR(17)652017
Using high speed imaging of the divertor volume, the region close to the X-point in MAST is shown to be quiescent. This is confirmed by three different analysis techniques and the quiescent X-point region (QXR) spans from the separatrix to the N = 1.02 flux surface. Local reductions to the atomic density and effects associated with the camera vie…
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CCFE-PR(17)632017
Experiments have been carried out on the MAST and JET tokamaks intended to compare the electrical resistivity of the plasma with theoretical formulations. The tests consist of obtaining motional stark effect (MSE) measurements in MHD-free plasmas during plasma current ramp-up (JET and MAST), ramp-down (MAST) and in stationary state (JET and MAST). …
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CCFE-PR(17)482017
The ITER tokamak needs to sustain a plasma in a regime of high energy confinement (H-mode) to exceed fusion breakeven where power output exceeds input. H-mode plasmas are typically unstable to edge localised modes (ELMs), in which plasma escapes and strikes the plasma facing components. Scaled up to ITER, the energy released by ELMs can cause criti…
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CCFE-PR(17)602017
Reciprocating Mach probe data is used to estimate the radial wave number of oscillatory zonal flows in Ohmic MAST plasma. An intermittent 10kHz mode is detected in the wavelet decomposition and windowed spectra of plasma potential fluctuations of the MAST tokamak edge plasma. Previously, this mode has been identified as a Geodesic Acoustic Mode (GA…
Showing 111 - 120 of 234 UKAEA Paper Results