Journals

Showing 1 - 7 of 7 Journals Results
2015
CCFE-PR(15)46

A consistent deterioration of global confinement in H-mode experiments has been observed in JET [1] following the replacement of all carbon Plasma Facing Components (PFCs) with an all metal (‘ITER-like’) wall (ILW). This has been correlated to the observed degradation of the pedestal confinement, as lower electron temperature (T e ) values are …

Preprint Published
2014

The former all-carbon wall on JET has been replaced with beryllium in the main torus and tungsten in the divertor to mimic the surface materials envisaged for ITER. Comparisons are presented between Type I H-mode characteristics in each design by examining respective scans over deuterium fuelling and impurity seeding, required to ameliorate exhaust…

Published
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…

Published
2012

Recent infra-red measurements of divertor power loads on JET and AUG [1], revealed that the inter-ELM power width at the outer mid-plane in attached ELMy H-modes does not exhibit any noticeable scaling with machine size [1]. Making use of these results to calculate the effective radial heat diffusivity, and then including this in parametrized expre…

Published
2010

The retention of deuterium fuel during MAST discharges has been studied using the method of global gas balance. The results show that with inter-shot 4 He- GDC, the total number of particles retained for a discharge increases with total number of injected particles, and the total retention fraction stays very high, mostly around 80%, and can be alm…

Published
2010

Pellet material deposited in a tokamak plasma experiences a drift towards the low field side of the torus induced by the magnetic field gradient. Plasma fuelling in ITER relies on the beneficial effect of this drift to increase the pellet deposition depth and fuelling efficiency. It is therefore important to analyse this phenomenon in present machi…

Published
2009

Experiments on the Alcator C-Mod and JET tokamaks with identical values of nondimensional variables at the pedestal top are expected to have the same local plasma transport for a ratio > 4 in absolute size and thus can help to clarify other effects in pedestal formation. At the high and low fields (7.9 T, 1.4 T respectively) involved, natural-densi…

Published