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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-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…
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UKAEA-STEP-PR(23)102023
In this work, we present the results of first-of-their-kind nonlinear local gyrokinetic simulations of electromagnetic turbulence at mid-radius in the burning plasma phase of the conceptual high-β, reactor-scale, tight-aspect-ratio tokamak STEP (Spherical Tokamak for Energy Production). A prior linear analysis in D.Kennedy et al. submitted to Nucl…
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UKAEA-CCFE-PR(23)812023
Linear and nonlinear gyrokinetic simulations are performed in experimentally relevant scenarios built from a MAST case where a microtearing mode instability dominates at ion Larmor radius scale. This collisional microtearing mode instability appears only when a vel…
Showing 1 - 10 of 53 UKAEA Paper Results