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UKAEA-CCFE-PR(18)652018
During the 2015-2016 JET campaigns many efforts have been devoted to the exploration of high-performance plasma scenarios envisaged for DT operation in JET. In this paper we review various key recent hybrid discharges and model the combined ICRF+NBI heating. These deuterium discharges with deuterium beams had the ICRF antenna frequency tuned to mat…
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UKAEA-CCFE-PR(19)102018
This paper outlines an approach towards improved rigour in tokamak turbulence transport model validation within integrated modelling. Gaussian process regression (GPR) techniques were applied for profile fitting during the preparation of integrated modelling simulations. This allows for rigourous sensitivity tests of prescribed initial and bound…
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UKAEA-CCFE-PR(18)542018
Neoclassical and turbulent heavy impurity transport in tokamak core plasmas are determined by main ion temperature, density and toroidal rotation profiles. Thus, in order to reproduce experimental behaviour of W accumulation, integrated modelling of main ion heat and particle transport is a vital prerequisite. For the first time, the quasilinear …
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UKAEA-CCFE-PR(18)132018
For the first time, over five confinement times, the self-consistent flux driven time evolution of heat, momentum transport and particle fluxes of electrons and multiple ions including Tungsten (W) is modeled within the integrated modeling platform JETTO [Romanelli M et al PFR 2014], using first principle-based codes : namely, QuaLiKiz [Bourd…
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UKAEA-CCFE-PR(18)102018
In Ion-Temperature-Gradient (ITG) driven turbulence, the resonance condition leads to ion particle turbulent transport coefficients significantly larger than electron particle turbulent transport coefficients. This is shown in non-linear gyrokinetic simulations and explained by an analytical quasilinear model. It is then illustrated by JETTO-QuaLi…
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UKAEA-CCFE-PR(18)32018
Recent studies have shown that on JET with the Be/W ITER-like wall (JET-ILW) in high beta discharges with high D2 gas rates the inter-ELM temperature pedestal growth is saturated half way through the ELM cycle, leading to plasmas with reduced confinement, and that the linear MHD stability of these pedestals is inconsistent with the Peeling-Ballooni…
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CCFE-PR(17)422017
Quantitative comparisons are presented between gyrokinetic simulations and experimental values of the carbon impurity peaking factor in a database of JET H-modes during the carbon wall era. These plasmas feature strong NBI heating, hence high values of toroidal rotation and correponding gradient. Furthermore, the carbon profiles present particularl…
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CCFE-PR(17)472017
Heavy impurities, such as tungsten (W), can exhibit strongly poloidally asymmetric density profiles in rotating or radio frequency heated plasmas. In the metallic environment of JET, the poloidal asymmetry of tungsten enhances its neoclassical transport up to an order of magnitude, so that neoclassical convection is expected to dominate over turbul…
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CCFE-PR(16)542016
The recently proposed set of zeroth-order moment equations to model poloidal density asymmetries induced by temperature anisotropies in rotating tokamak plasmas (R. Bilato et al., Nuclear Fusion 54 (2014) 072003) is here extended to account for the effects of the localization of the ion cyclotron (IC) resonance on the poloidal inhomogeneity of the …
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CCFE-PR(16)452016
It is shown that ITG turbulence close to the threshold exhibits a long time behaviour, with smaller heat fluxes at later times. This reduction is connected with the slow growth of long wave length zonal flows and, consequently, the numerical dissipation on these flows must be sufficient small. Close to the nonlinear threshold for turbulence generat…
Showing 31 - 40 of 49 UKAEA Paper Results