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CCFE-PR(15)272015
The high-k (7 . k??i . 11) wavenumber spectrum of density fluctuations has been measured for the first time in MAST [B. Lloyd et al, Nucl. Fusion 43, 1665 (2003)]. This was accomplished with the first implementation of Doppler backscattering (DBS) for core measurements in a spherical tokamak. DBS has become a well-established and versatile diagnost…
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2014
The JET ITER-like Wall (ILW) provides the same plasma facing component configuration as ITER during its active phase: beryllium in the main chamber and tungsten in the divertor. Moving from a carbon-based wall to an all metal wall requires some operational adjustment. The reduction in radiation at the plasma edge and in the divertor can lead to hig…
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2013
Remote handling operations at JET have encountered many challenges to achieve the installation of the ILW beryllium sliced wall during the Enhanced Performance stage 2 (EP2) shutdown of JET. This was a demanding and challenging activity which was based on the experience gained from a period of over 15 years (20000 hrs. operations) of JET In-Vessel …
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2012
Lower hybrid current drive (LHCD) with modest powers ( 10% of the total power input) has been used for the first time to completely stabilize performance limiting neoclassical tearing modes in many COMPASS-D tokamak discharges. The stabilizing effect in these experiments is consistent with a reduction in the free energy available in the current pro…
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2011
Major developments on MAST have enabled important advances in support of ITER and the physics basis of a spherical tokamak (ST) based component test facility (CTF), as well as providing new insight into underlying tokamak physics. For example, L-H transition studies benefit from high spatial and temporal resolution measurements of pedestal profile …
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2009
Electron Bernstein wave (EBW) assisted plasma current start-up has been demonstrated for the first time in a tokamak. It was shown that plasma currents up to 17 kA can be generated non- inductively by 100 kW of RF power injected. With optimized vertical field ramps, plasma currents up to 33 kA have been achieved without the use of solenoid flux. It…
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2009
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2007
There is a comprehensive, closely-interlinked electron Bernstein wave (EBW) programme on MAST covering heating experiments, plasma start-up studies, plasma emission measurements, theory and modelling. In this paper we report on proof-of-principle EBW heating experiments conducted on MAST with a 60 GHz, 1 MW gyrotron complex. A 28 GHz (200 kW) EBW s…
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2006
Burning plasma spherical tokamaks (STs) rely on off-axis current drive (CD) and nonsolenoid start-up techniques. Electron Bernstein waves (EBWs) may provide efficient off-axis heating and CD in high-density ST plasmas. EBWs may also be used in the plasma start-up phase because EBW absorption and CD efficiency remain high even in relatively cold pla…
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2005
JET supports ITER both in development of technology and in torus operations. The latter include the study of ITER-like scenarios, operation in tritium (a trace tritium campaign has recently been completed), mitigation of ELMs and disruptions, investigation of tritium retention, real time control of plasma parameters, and control of extreme plasma s…
Showing 21 - 30 of 46 UKAEA Paper Results