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UKAEA-CCFE-CP(19)532019
During edge localised modes (ELMs) high heat fluxes are incident on divertor targets, which future fusion devices will not withstand [1]. A solution to reduce the heat fluxes could be the new Super-X divertor, which will be tested on the MAST-U tokamak. The divertor has an increased connection length, magnetic flux expansion and is designed to reta…
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UKAEA-CCFE-CP(19)422019
Plasma detachment needs to be achieved in ITER [1] and future devices such as DEMO to dissipate most of the power in the Scrape-Off-Layer (SOL) and reduce the particle flux reaching the divertor targets. In order to enhance our capability to improve current, and design future tokamaks, we must improve our understanding of the relative effect on det…
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UKAEA-CCFE-CP(19)212019
A firm grasp of transport processes perpendicular to the magnetic field line is required in order to understand and predict heat and particle fluxes to divertor components in tokamaks. Perpendicular transport from the hot core into the scrape-off layer (SOL) upstream impacts the SOL profile at the divertor via parallel streaming along the magnetic …
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UKAEA-CCFE-PR(19)552019
In ITER and DEMO, achieving detachment at lower densities would allow to reduce the amount of impurity seeded and to improve confinement by running at lower separatrix densities. Analytic models predict that a increase of total flux expansion would allow such a reduction in upstream density at detachment. However, both experiments and modelling …
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UKAEA-CCFE-PR(19)072018
Ray-tracing techniques are applied to divertor filtered imaging, a diagnostic that has long been plagued by polluting reflected light features in metal walled fusion machines. A physically realistic surface reflection model is developed from a Cook-Torrence microfacet BRDF model. Camera calibration images of in-vessel point lights at JET are use…
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UKAEA-CCFE-PR(19)032018
A new 1D divertor plasma code, SD1D, has been used to examine the role of recombination, radiation, and momentum exchange in detachment. Neither momentum or power losses by themselves are found to be sufficient to produce target ion flux rollover in detachment; radiative power losses are required to a) limit and reduce the ionization source and …
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UKAEA-CCFE-PR(18)362018
This paper further analyses the EDGE2D-EIRENE simulations presented by [Chankin et al (2017 Nucl. Mater. Energy 12 273], of L-mode JET plasmas in vertical-vertical (VV) and vertical-horizontal (VH) divertor configurations. As expected, the simulated outer divertor ionisation source peaks near the separatrix in VV …
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CCFE-PR(17)752017
This paper presents the use of a novel modelling technique based around intermittent transport due to filament motion, to interpret experimental profile and fluctuation data in the scrape-off layer (SOL) of JET during the onset and evolution of a density profile shoulder. Three cases are studied at different points in a density ramp experiment wher…
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CCFE-PR(17)032017
Statistical analysis of the ion flux to the JET outer-wall is conducted in outer-wall limiter mounted Langmuir probe (OLP) time-series across a wide range of plasma current and line-averaged density during Ohmically heated horizontal target L-mode plasmas. The mean, _, and the standard deviation, _, of the ion-saturation current measured by the OLP…
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CCFE-PR(16)672016
We show that a central characteristic of Super-X divertors, parallel area expansion fR (de ned as the ratio of the elementary area normal to the magnetic field at the target to that at the X-point, also known as total flux expansion), significantly changes the characteristics of the target plasma for fixed upstream conditions. To isolate the effect…
Showing 41 - 50 of 53 UKAEA Paper Results