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UKAEA-CCFE-PR(25)2802022
In this work a spatial dimension is added to the description of radiative detachment in MAST-U super-X divertor plasmas. This magnetic configuration is hypothesized to achieve improved heat load spreading at the divertor target and more particle-, heat- and momentum losses through plasma-neutral interactions than conventional exhaust solutions. Fil…
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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(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(24)2372021
Control of the detachment front between the target and the X-point is necessary for minimizing the effect of detachment on the core plasma (core radiation and loss of confinement) and maximizing the divertor functions (reduction of target heat load and sputtering, He pumping). However, such control has been difficult in experiments. The SOLPS-IT…
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UKAEA-CCFE-PR(23)1012021
The role of neutral and charged hydrogenic molecules in detached regimes of tokamak plasmas is investigated using simplified 1D parallel numerical models. Using MAST-Upgrade like conditions, simulations are implemented to study the rollover of target flux in upstream density scan and target temperature scan. It is found that if H2 and H2+ are cons…
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UKAEA-CCFE-PR(21)822021
The benefits of an optimised Super-X divertor configuration in mitigating the steady-state power and particle fluxes to the surfaces of the MAST Upgrade divertor have been quantified by performing a detailed comparison with a conventional divertor for the first time. In otherwise identical plasmas with conventional and Super-X divertor configu…
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UKAEA-CCFE-CP(21)102021
This paper shows experimental results from the TCV tokamak that indicate plasma-molecule interactions involving D+2 and possibly D− play an important role as sinks of energy (through hydrogenic radiation as well as dissociation) and particles during divertor detachment if low target temperatures (< 3 eV) are achieved. Bot…
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UKAEA-CCFE-CP(21)062021
In this work we provide experimental insights into the impact of plasma-molecule interactions on divertor detachment by applying new spectroscopic analysis techniques to the hydrogen Balmer line series to investigate how both atom and plasma-molecule interactions impact particle balance. Our analysis on a representative L-mode TCV density ramp dis…
Showing 11 - 20 of 27 UKAEA Paper Results