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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 (likely $D_2^+$), 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, lea…
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UKAEA-CCFE-PR(23)1282022
Predictions of the impact of charge-exchange (CX) reactions on beam ions in the MAST Upgrade spherical tokamak have been compared to measurements carried out with a fission chamber (neutron fluxes) and a Fast Ion Deuterium-Alpha (FIDA) diagnostic. A simple model was developed to reconstruct the outer-midplane neutral density based on Thomson sca…
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UKAEA-STEP-PR(23)072022
To mitigate the issue of plasma exhaust in reactor scale tight aspect ratio tokamaks such as STEP (Spherical Tokamak for Energy Production), a double-null (DN) configuration is thought to be advantageous over a single-null (SN) configuration. However, practical control of the plasma vertical stability will likely lead to an oscillation around th…
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UKAEA-CCFE-PR(23)942022
Divertor detachment requires plasma-neutral interactions which dissipate momentum, power and particles simultaneously. Plasma-molecular interactions can result in molecular ions which react with the plasma. This can contribute to detachment through molecular activated recombination (MAR) and molecular activated dissociation (MAD), both of which cre…
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UKAEA-CCFE-PR(23)082022
The role of ion-molecule elastic collisions (specifically D+−D2 collisions) in strongly detached divertor conditions has been studied in the MAST-U Super-X configuration using SOLPS-ITER. Two strongly detached steady state solutions, one obtained through a main-ion (D2) fuelling scan and the other through an impurity (N) seeding scan at fixed …
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UKAEA-CCFE-PR(23)012022
The design and understanding of alternative divertor configurations may be crucial for achieving acceptable steady-state heat and particle material loads for magnetic confinement fusion reactors. Multiple x-point alternative divertor geometries such as Snowflakes and Xpoint targets have great potential in reducing power loads, but have not yet b…
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UKAEA-CCFE-PR(22)542022
As tokamak research moves to reactor conditions, the control of a stable, optimally-detached divertor plasma has become increasingly relevant. Simple predictions of such detachment control have been performed previously using the Detachment Location Sensitivity (DLS) model of detachment. In this study the DLS model is extended and combined with SOL…
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UKAEA-CCFE-PR(22)232022
In this paper we a first qualitative analysis of the atomic and molecular processes at play during detachment in the MAST-U Super-X divertor, using divertor spectroscopy data. Our analysis indicates a wide operational regime of detachment of the MAST-U super-X divertor, which can be roughly separated in four phases: 1) The ionisation fro…
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UKAEA-CCFE-PR(22)082022
MAST-U has recently started operating with a Super-X divertor, designed to increase total flux expansion and neutral trapping, both predicted through simple analytic models and SOLPS calculations to reduce the plasma and impurity density detachment thresholds. In this study, utilising the SOLPS-ITER code, we are quantifying the possible gain allowe…
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UKAEA-CCFE-PR(25)2772021
In a snowflake (SF) divertor, two magnetic field nulls are placed close to each other, creating four strike points (SPs) compared to two in a standard X-point divertor. In preparation for MAST-U experiments, magnetic configurations with the standard and SF divertors with various locations and separation distances of the nulls were modeled using …
Showing 21 - 30 of 58 UKAEA Paper Results