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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)2332024
Starting from the assumption that saturation of plasma turbulence driven by temperature-gradient instabilities in fusion plasmas is achieved by a local energy cascade between a long-wavelength outer scale, where energy is injected into the fluctuations, and a small-wavelength dissipation scale, where fluctuation energy is thermalized by particle…
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UKAEA-CCFE-CP(25)112023
Retention of tritium in structural materials of a fusion reactor is a concern for tritium accountancy, maintenance, and decommissioning. Plasma facing materials will be exposed to high temperatures, neutron damage and hydrogen isotopes. The damage caused by these conditions is a large area of exploration for fusion, with many questions still to…
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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(24)2172023
Fusion energy offers the potential for a near limitless source of low-carbon energy and is oftenregarded as a solution for the world’s long-term energy needs. To realise such a scenario requiresthe design of high-performance fusion reactors capable of maintaining the extreme conditionsnecessary to enable fusion. Turbulence …
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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)1412023
In this paper, we summarize our recent work on gyrokinetic applications in electron- positron and non-neutral plasma. The electrostatic stability of electron-positron plasmas was investigated in dipole and slab geometry, with and without ion admixture. The gyrokinetic dispersion relation was derived and, for the slab case, extended to non-neutra…
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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 14 UKAEA Paper Results