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UKAEA-CCFE-PR(23)1322023
First quantitative analysis of the detachment processes in the MAST Upgrade Super-X divertor show an unprecedented impact of plasma-molecular interactions involving molecular ions, resulting in strong ion sinks, leading to a reduction of ion target flux. This starts to occur as the ionisation source detaches from the target, leading to a build-up o…
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UKAEA-CCFE-PR(23)1082023
This paper addresses two key issues regarding plasma exhaust in future fusion reactors. Firstly, using newly developed spectroscopic models to measure the divertor concentration of Ne and Ar, it is shown that the experimental detachment threshold on ASDEX Upgrade with Ar-only, an Ar+N mixture, and a Ne+N mixture scales as expected in comparison wit…
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UKAEA-CCFE-PR(21)472021
Visible emission from a broad range of tungsten charge states has complicated plasma ion temperature and toroidal rotation measurements on the JET tokamak since the installation of the ITER-like wall. A plethora of charge exchange emission lines from ions up to W 56+ and 21 suspected magnetic dipole emission lines have so far been observed. In p…
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UKAEA-CCFE-CP(20)1232020
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UKAEA-CCFE-CP(19)482019
An understanding of the plasma edge and divertor is essential for predicting the performance of next-step machines such as ITER. Transport codes used to study the divertor behaviour [1] employ atomic physics data in two applications. The first is to predict the power radiated by the fuel and impurity atoms, which is carried out as a post-processing…
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UKAEA-CCFE-CP(19)202019
Reducing the plasma power exhaust impacting on plasma facing components during steady state operation is one of the major design issues in future tokamaks such as ITER. Impurity seeding, e.g. with N, is one method of achieving this and has been used for a long time in tokamak research [1]. In this work we exploit a recently developed spectroscopic …
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UKAEA-CCFE-PR(18)682018
Helium is widely used as a fuel or minority gas in laboratory fusion experiments, and will be present as ash in DT thermonuclear plasmas. It is therefore essential to have a good understanding of its atomic physics. To this end He II population modelling has been undertaken for the spectroscopic levels arising from shells with principal quantum…
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UKAEA-CCFE-PR(18)312018
Spectra line power by medium and heavy weight elements is a main source of radiative loss in tokamak plasma and sets operational limits on the design of ITER and DEMO. The preferred comprehensive basis of impurity line power coefficients provided by ADAS is theoretical, using the Autostructure code with distorted wave electron impact cross-sections…
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CCFE-PR(15)482015
Carbon and nitrogen impurity transport coefficients are determined from gas puff experiments carried out during repeat L-mode discharges on the Mega-Amp Spherical Tokamak (MAST) and compared against a previous analysis of helium impurity transport on MAST. The impurity density profiles are measured on the lowfield side of the plasma, therefore this…
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2014
Time-dependent helium gas puff experiments have been performed on the Mega Ampere Spherical Tokamak (MAST) during a two point plasma current scan in L-mode and a confinement scan at 900 kA. An evaluation of the He II spectrum line induced by charge exchange suggests anomalous rates of diffusion and inward convection in the outer regions of both L-m…
Showing 1 - 10 of 16 UKAEA Paper Results