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UKAEA-CCFE-CP(19)382019
As part of the preparation for the second JET DT campaign (DTE2), a series of isotope control experiments in H/D mixtures [1] have shown that NBI fuelling species has only a weak effect on the core isotope composition, which remains determined by the edge H/D ratio and therefore by the injected gas.
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UKAEA-CCFE-CP(19)332019
The initial Ohmic current ramp phase of JET hybrid plasmas, including a current ‘overshoot’ before the main heating, is used to optimise the q-profile shape to allow access to high β and avoid MHD instabilities [1]. Such hybrid plasmas have never been operated using tritium (T) or mixed deuterium-tritium (D-T) fuel. However, experiments with i…
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UKAEA-CCFE-PR(19)622019
The pedestal structure, ELM losses and linear MHD stability are analysed in a series of JET-ILW H and D type I ELMy H-mode plasmas. The pedestal pressure (pPED) is typically higher in D than in H at the same input power, with the difference mainly due to lower density in H than in D. At the same input power, the pedestal electron pres…
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UKAEA-CCFE-PR(19)112019
Increased neutralisation and hence injected neutral beam power can be achieved by increasing the neutraliser target. This has the potential to increase the loading on the ion source backplate due to backstreaming electrons. Measurements of the backplate power loading due to backstreaming electrons are presented for the JET EP2 neutral beam injector…
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UKAEA-CCFE-CP(18)012018
The dependence of JET neutron deficit and energy balance on neutral beam (PINI) selection has been investigated experimentally. The discrepancy between neutrons predicted and measured during JET pulses has consistently deviated, with the measured neutrons typically being lower than expected by simulation. A number of investigations into this hav…
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UKAEA-CCFE-PR(18)812018
Fast ion synergistic effects were studied by predictive modelling of JET best performing pulses for various levels of Neutral Beam (NB) and Radio Frequency (RF) power. Calculated DD neutron yields were analysed with the intention of separating the impact of sheer synergistic effects due to changes in fast ion (FI) distribution function (DF) from su…
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UKAEA-CCFE-PR(18)402018
Experimental evidence is presented of a discrepancy between the predicted and measured D-D fusion products rates on MAST. Both the neutron and proton production rates, measured independently with a neutron camera and charged fusion product detector array, are approximately 40 % lower than those predicted by TRANSP/NUBEAM codes. This deficit is scen…
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UKAEA-CCFE-PR(18)152018
Particle transport is of a great importance for understanding physics of tokamak plasmas and planning future experiments on larger machines such as ITER. The subject was intensively studied in the past, particularly in relation to density peaking and presence of anomalous inward particle convection in L- and H-mode. While in the L-mode case presenc…
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CCFE-PR(17)632017
Experiments have been carried out on the MAST and JET tokamaks intended to compare the electrical resistivity of the plasma with theoretical formulations. The tests consist of obtaining motional stark effect (MSE) measurements in MHD-free plasmas during plasma current ramp-up (JET and MAST), ramp-down (MAST) and in stationary state (JET and MAST). …
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CCFE-PR(17)762017
During development of a high-performance hybrid scenario for future deuterium–tritium experiments on the Joint European Torus, an increased level of fast ion losses in the MeV energy range was observed during the instability of high-frequency n = 1 fishbones. The fishbones are excited during deuterium neutral beam injection combined with…
Showing 41 - 50 of 61 UKAEA Paper Results