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UKAEA-CCFE-CP(20)692019
Elliptical AE (EAE) and TAE mode instabilities have been observed in hydrogen-rich (nH/(nH+nD)~70-90% JET discharges of so-called “three-ion scenario”, i.e. D-(3He)-H three ion ICRH scenario [1], which is characterized by strong absorption of radio frequency waves a…
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UKAEA-CCFE-PR(19)252019
Deuterium pellets are injected into initially pure hydrogen H-mode plasma in order to control H:D isotope mixture. The pellets are deposited in outer 20% of minor radius, similar to that expected in ITER creating transiently hollow electron density profiles. The isotope mixture of H:D ~ 45:55% is obtained in the core with pellet fuelling throughput…
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UKAEA-CCFE-CP(18)112018
Results of simulations of the sawtooth-induced redistribution of fast ions in JET and ITER with the code OFSEF are presented. The dependence of the redistribution on the particle parameters (energy and pitch angle) is studied. The redistribution of the trapped and marginally passing particles is found to exhibit barrier-like behaviour at the separa…
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UKAEA-CCFE-PR(18)512018
An effect due to fusion born triton production has been observed in JET high-performance deuterium plasma discharges with NBI and H-minority ICRF heating, using DD and DT neutron spectrometry as well as fusion product loss measurements. The observations show that increase of the triton burn up rate leads to decrease of second harmonic ωcH
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UKAEA-CCFE-PR(18)282018
Fishbones are ubiquitous in high-performance JET plasmas and are typically considered to be unimportant for scenario design. However, during recent high-performance hybrid experiments, sporadic and explosive fishbones have been observed which correlate with a reduction in performance and main chamber hotspots. Clear evidence has been obtained of fu…
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UKAEA-CCFE-PR(18)142018
Measurements are reported of electromagnetic emission close to the cyclotron frequency of energetic ions in JET plasmas heated by waves in the ion cylotron range of frequencies (ICRF). Hydrogen was the majority ion species in all of these plasmas. The measurements were obtained using a sub-harmonic arc detection (SHAD) system in the transmission li…
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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…
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CCFE-PR(15)232015
Comparing with ITER, the experimental fusion machine under constraction, the next step test fusion power plant, DEMO will be characterized by very long pulse/steady-state operation and much higher plasma volume and fusion power. The substantially increased level of neutron and gamma fluxes will require reducing the physical access to the plant. It …
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2015
The Joint European Torus (JET, Culham, UK) is the largest tokamak in the world. JET has been upgraded over the years and recently it has also become a test facility of the components designed for ITER, the next step fusion machine under construction in Cadarache (France). At JET, the neutron emission profile of Deuterium (D) or Deuterium-Tritium (D…
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CCFE-PR(15)1232015
Heating single ion species plasmas with ICRF is a challenging task: Fundamental ion cyclotron heating (w = w ci ) suffers from the adverse polarization of the RF electric fields near the majority cyclotron resonance while second harmonic heating (w = 2w ci ) typically requires pre-heating of the plasma ions to become efficient. Recently, w = 2w ci …
Showing 21 - 30 of 42 UKAEA Paper Results