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UKAEA-CCFE-CP(23)462022
Accurate and consistent measurements of the electron temperature (Te) profile are paramount for current fusion experiments, like JET, and future devices, such as ITER. In high performance plasmas in JET and TFTR, electron cyclotron emission (ECE) measurements for central Te>5 keV were systematically found to be up to 20%…
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UKAEA-CCFE-CP(22)052022
A study of a dataset of JET H-mode plasma with the Be/W ITER-like wall (JET-ILW) shows that reaching the edge MHD ballooning limit leads to confinement degradation. However, unlike JET plasmas with a carbon wall (JET-C), the JET-ILW plasmas stay in a marginal dithering phase for a relatively long period, associated with a higher (20%) H-mode den…
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UKAEA-CCFE-CP(23)612021
The relative role of particle transport and edge fuelling in setting the H-mode density pedestal is still a key open question [1]. Although reduced pedestal models have proven successful in predicting the pedestal pressure for a wide range of plasma scenarios [2,3,4], they lack a first principle based, predictive model for the edge density. Pred…
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UKAEA-CCFE-CP(23)302021
Many of the essential data analysis procedures for a tokamak experiment rely on the knowledge of the magnetic field structure obtained from MHD force balance. On JET, the code that is responsible for computing the magnetic equilibrium is called EFIT++. Interpretation of JET data has been challenging due to inconsistencies between diagnostic meas…
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UKAEA-CCFE-CP(23)192021
Control of plasma H:D isotope mix using solely shallow pellets (in H or D) was demonstrated in recent experiments, attaining ~50%:50% ratio. The isotope mix propagates from the edge to the core on the confinement timescale. Isotope dependence of energy confinement is within error bar to scaling laws. A dataset is collected for different pellet s…
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UKAEA-CCFE-PR(21)072021
A study of a dataset of JET plasma with the Be/W ITER-like wall (JET-ILW) shows that reaching the edge MHD ballooning limit leads to confinement degradation. However, unlike JET plasma with a carbon wall (JET-C), the JET-ILW plasma stays in a marginal dithering phase for a relatively long period, associated with a higher a ( 20%) H-mode density lim…
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UKAEA-CCFE-CP(20)992020
Unraveling the conditions that permit access to H-mode continues to be an unresolved physics issue for tokamaks, and accurate extrapolations are important for planning ITER operations and DEMO design constraints. Experiments have been performed in JET, with the ITER-like W/Be wall, to increase the confidence of predictions for the L-H transition po…
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UKAEA-CCFE-CP(19)412019
An n = 1 locked, or slowly rotating, mode has been observed in most pulses prior to JET disruptions. However, a small fraction of non-disruptive pulses has a locked mode which eventually vanishes without disruption. Hence, on JET the locked mode amplitude is routinely used as an indicator of unhealthy plasma. There are two threshold levels…
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UKAEA-CCFE-PR(19)202019
The paper presents an analysis of disruptions occurring during JET-ILW plasma operations covering the period from the start of ILW (ITER-like wall) operation up to completion of JET operation in 2016. The total number of disruptions was 1951 including 466 with deliberately induced disruptions. The average disruption rate of unintended disruptions i…
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2016
There is experimental evidence that the pedestal dynamics in type-I ELMy H-mode discharges is significantly affected by a change in the recycling conditions at the tungsten plasma-facing components (W-PFCs) after an ELM event. The integrated code JINTRAC has been employed to assess the impact of recycling conditions during type-I ELMs in JET ITER-l…
Showing 11 - 20 of 28 UKAEA Paper Results