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2014
The major aspects linked to the use of the JET auxiliary heating systems: NBI, ICRF and LHCD, in the new JET ITER-like wall (JET-ILW) are presented. We show that although there were issues related to the operation of each system, efficient and safe plasma heating was obtained with room for higher power. For the NBI up to 25.7MW was safely injected;…
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2013
This paper reports the impact on confinement and power load of the high-shape 2.5MA ELMy H-mode scenario at JET of a change from an all carbon plasma facing components to an all metal wall. In preparation to this change, systematic studies of power load reduction and impact on confinement as a result of fuelling in combination with nitrogen seeding…
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2012
Using theoretical arguments, a simple scaling law for the size of the intrinsic rotation observed in tokamaks in the absence of a momentum injection is found: The velocity generated in the core of a tokamak must be proportional to the ion temperature difference in the core divided by the plasma current, independent of the size of the device. The co…
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2011
New transport experiments on JET indicate that ion stiffness mitigation in the core of a rotating plasma, as described by Mantica et al. [ Phys. Rev. Lett. 102, 175002 (2009) ] results from the combined effect of high rotational shear and low magnetic shear. The observations have important implications for the understanding of improved ion core con…
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2008
Impurity transport is an important topic for ITER as impurity density in tlie core has to stay below a relative concentration of 5 x 10~^ [1] to reach ignition conditions. The reasons for that is mainly impurity radiation leading to cooling. In the edge region on the other hand site, higher impurity densities, going along with radiation energy loss…
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2008
Charge exchange Recombination Spectroscopy (CXRS) plays a pivotal role in the diagnostics of hot fusion plasmas and is implemented currently in most of the operating devices. In the present report the main features of CXRS are summarized and supporting software packages encompassing "Spectral Analysis Code CXSFIT", "Charge Exchange Analysis Package…
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2007
Type-I edge-localized modes (ELMs) have been mitigated at the JET tokamak using a static external n 1 perturbation field generated by four error field correction coils located far from the plasma. During the application of the n 1 field the ELM frequency increased by a factor of 4 and the amplitude of the D signal decreased. The energy loss per ELM…
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2006
During a recent reversed toroidal field (B T) campaign at the Joint European Torus (JET), experiments were performed to investigate the effect on sawteeth of neutral beam injection (NBI)-driven toroidal plasma rotation counter to the direction of the toroidal plasma current and B T . A power scan at constant density has permitted analytical continu…
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2001
Simultaneous current ramping and application of lower hybrid heating and current drive (LHCD) have produced a region with zero current density within measurement errors in the core of JET tokamak optimized shear discharges. The reduction of core current density is consistent with a simple physical explanation and numerical simulations of radial cur…
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1997
Modern charge-coupled-device (CCD) detectors can achieve peak quantum efficiencies of 90%, compared with less than 10% for the photocathode of an electron multiplier. We report on laboratory tests of examples of these two detector technologies to evaluate their relative performance for precision Doppler spectroscopy of laboratory plasmas. The tests…
Showing 41 - 50 of 50 UKAEA Paper Results