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UKAEA-CCFE-CP(18)052018
Pellets are used in ASDEX Upgrade [1] to control plasma density under conditions of ELM control or divertor detachment. In experiments presented here direct fuelling by gas is negligible. Relative pellet size and pellet deposition are aimed to approach those in ITER but differences still remain. ELMs are controlled by n=2 RMPs in feed forward mode …
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UKAEA-CCFE-CP(18)042018
An edge resonant transport layer has been found to explain many aspects of fast-ion confinement under symmetry breaking 3D edge perturbations, such as edge localized modes (ELMs) and externally applied magnetic perturbations (MPs). Experimental measurements in the ASDEX Upgrade (AUG) tokamak show that fast-ion losses in the presence of symmetry bre…
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UKAEA-CCFE-PR(18)822018
Recent experiments on TCV have made significant progress toward partial detachment of the outer divertor in neutral beam heated H-mode plasmas. The heating power required to enter H-mode was measured in a range of divertor configurations, finding that, in the vicinity of the PL-H/ne curve, the threshold power is largely independent of the poloidal …
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UKAEA-CCFE-PR(18)692018
The impact of the three-dimensional (3D) tokamak geometry from external magnetic perturbations (MPs) on the local edge stability has been examined in high confinement mode (H-mode) plasmas with edge localised modes (ELMs) in ASDEX Upgrade. The 3D geometry has been probed using rigidly rotating MP fields. The measured distortions of the plasma bound…
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UKAEA-CCFE-PR(18)542018
Neoclassical and turbulent heavy impurity transport in tokamak core plasmas are determined by main ion temperature, density and toroidal rotation profiles. Thus, in order to reproduce experimental behaviour of W accumulation, integrated modelling of main ion heat and particle transport is a vital prerequisite. For the first time, the quasilinear …
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UKAEA-CCFE-PR(18)522018
Partial detachment is the desired regime for the baseline burning plasma scenario in ITER and next-step devices, as it allows to disspate the majority of the energy carried by charged particles through the scrape-off-layer (SOL) and thus avoids localised heat flux deposition in the divertor region. The COMPASS tokamak is equipped with an open diver…
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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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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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2017
Extensive modelling efforts of the plasma response to the resonant magnetic perturbation fields, utilized for controlling the edge localized mode (ELM), help to identify the edge-peeling response as a key factor, which correlates to the observed ELM mitigation in several tokamak devices, including MAST, ASDEX Upgrade, EAST, and HL-2A. The recently …
Showing 11 - 20 of 25 UKAEA Paper Results