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UKAEA-CCFE-PR(25)2882023
Dedicated experiments were performed in JET DTE2 plasmas for obtaining α-particle bump-on-tail (BOT) distribution aiming at exciting Alfvén Eigenmodes (AEs) in baseline tokamak plasma scenario with safety factor q(0)~1. NBI-only heating with modulated power was used so that fusion-born α-particles were the only ions present in the MeV energy ran…
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UKAEA-STEP-PR(25)282023
Generation of Runaway Electrons (REs) during plasma disruptions, and their impact on plasma facing components, is of great concern for ITER and future reactors based on the tokamak concept. Current STEP (Spherical Tokamak for Energy Production) concept design flat top operating point features a plasma current higher than 20 MA and thus any plasm…
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UKAEA-CCFE-PR(23)022023
A toroidal Alfven eigenmode (TAE) has been observed driven by alpha particles in the Joint European Torus (JET). The observation was made in dedicated deuterium-tritium experiments where radio-frequency (RF) heating was absent, in the so-called “afterglow” period when neutral beam heating was removed. Agreement with reduced and perturbative mod…
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UKAEA-CCFE-CP(23)442022
Due to their relatively higher Vbeam/VAlvén ratio, spherical tokamaks are ideal to investigate high-frequency modes such as Compressional Alfvén Eigenmodes (CAEs) and Global Alfvén Eigenmodes (GAEs), and so they have been previously studied in MAST [1, 2]. Besides, the recently installed scintillator-based Fast-Ion Loss …
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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)352022
Understanding generation and mitigation of runaway electrons in disruptions is important for the safe operation of future tokamaks. In this paper we investigate runaway dynamics in reactor-scale spherical tokamaks. We study both the severity of runaway generation during unmitigated disruptions, as well as the effect that typical mitigation schem…
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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…
Showing 1 - 10 of 27 UKAEA Paper Results