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UKAEA-CCFE-PR(25)4052025
The ability to capture the isotope mass scaling of core confinement seen in experiment is validated with JETTO-TGLF for low power JET-ILW discharges across H, D and T. The cases analysed include Ohmic discharges spanning the linear and saturated Ohmic confinement regimes as well as a trio of L-modes. The TGLF saturation rules SAT1-SAT3 are seen to …
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UKAEA-CCFE-PR(25)3412025
Predictions of the pedestal temperature profile calculated using a model for ETG turbulent electron heat transport [A R Field et al 2023 Phil. Trans. Royal Soc. A 381 (2242) 20210228] are compared with the pedestal structure of JET-ILW (‘ITER-like wall’) H-mode plasmas over scans of the deuterium-tritium (D:T) isotope mix and hydrogenic gas fue…
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UKAEA-CCFE-PR(25)3392025
Fusion performance in a tokamak-reactor strongly depends on the confinement of thermalised α-particles (Helium (He) ash) in the core plasma region. Consequently, the development of He particle transport models and their validation in present experiments is an important step towards a more accurate prediction of fusion power production in future de…
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UKAEA-STEP-PR(26)052024
STEP is a spherical tokamak prototype power plant that is being designed to demonstrate net electric power. The design phase involves the exploitation of plasma models to optimise fusion performance subject to satisfying various physics and engineering constraints. A modelling workflow, including integrated core plasma modelling, MHD stability a…
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UKAEA-CCFE-PR(25)3762024
Magnetic stochastic perturbations can strongly influence cross-field transport in high β tokamak plasmas. The impact of stochastic magnetic fields on electron heat transport in MAST/MAST-U is studied over a range in collisionality. Different formulae, based on the Rechester-Rosenbluth and the semi-empirical Rebut-Lallia-Walkins models, are used to…
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UKAEA-STEP-PR(25)332024
A quasi-linear reduced transport model is developed from a database of high-β electromagnetic nonlinear gyrokinetic simulations performed with Spherical Tokamak for Energy Production (STEP) relevant parameters. This reduced transport model is based on a quasi-linear metric computed from linear gyrokinetic simulations and accounts for the effect of…
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UKAEA-STEP-PR(25)252024
This paper discusses the importance of parallel and perpendicular magnetic field perturbations in gyrokinetic simulations of electromagnetic instabilities and turbulence at mid-radius in the burning plasma phase of the conceptual high-β, reactor-scale, tight-aspect- ratio tokamak STEP. Previous studies have revealed the presence of unstable hybrid…
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UKAEA-CCFE-PR(24)2202023
Spherical tokamaks (STs) have many desirable features that make them an attractive choice for a future fusion power plant. Power plant viability is intrinsically related to plasma heat and particle confinement and this is often determined by the level of micro-instability driven turbulence. Accurate calculation of the properties of turbulent micro-…
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UKAEA-CCFE-PR(23)1532023
The results of a recent gyrokinetic analysis of turbulent transport driven by the electron temperature gradient (ETG) in the MAST pedestal are presented. During the inter-ELM period, the buildup rate of the electron density gradients is faster than that of the electron temperature gradients, possibly indicating the presence of an active electron th…
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UKAEA-STEP-PR(23)112023
We present herein the results of a linear gyrokinetic analysis of electromagnetic microinstabilites in the conceptual high−β, reactor-scale, tight-aspect-ratio tokamak STEP (Spherical Tokamak for Energy Production, https://step.ukaea.uk). We examine a range of flux surfaces between the deep core and the pedestal top for the two candidate flat…
Showing 1 - 10 of 55 UKAEA Paper Results