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UKAEA-CCFE-PR(25)2652025
The development of discrete strain at the microstructural scale during the onset of plasticity is potentially linked to fatigue crack nucleation in engineering alloys. Hence, quantifying such discrete strain and its evolution is a pathway to understand the microstructural influence on fatigue crack nucleation and to develop crack initiation mode…
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UKAEA-STEP-PR(25)272023
Electron Bernstein current drive (EBCD) systems are sensitive to plasma and launch conditions, and therefore require large parametric scans to optimise their design. One particular bottleneck in the simulation workflow is quasilinear modelling of current drive efficiency. Linear adjoint models are an attractive alternative, offering a ∼103× spee…
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UKAEA-STEP-PR(25)262024
STEP (Spherical Tokamak for Energy Production) is the UK’s reactor design programme aiming to demonstrate net electrical output from a spherical tokamak. STEP requires completely non-inductive current drive for the flat-top and the majority of the ramp-up/down phases. The majority of the current (~80%) is generated by a high bootstrap fraction…
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UKAEA-CCFE-PR(25)2732025
ERMES 20.0 is an open-source software which solves the Maxwell’s equations in frequency domain with the Finite Element Method (FEM). The new ERMES 20.0 is a significant upgrade from the previous ERMES 7.0. It introduces new features, modules, and FEM formulations to address the challenging problems commonly encountered in the design and analysis …
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UKAEA-CCFE-PR(25)2722025
The development and distribution of microscopic shear strain have been investigated using high-resolution digital image correlation at the onset of plastic deformation in face-centred cubic CoCrFeNi high entropy al- loys with different grain sizes. Microscopic strain localisation increased with grain size as shown by the presence of planar slip …
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UKAEA-CCFE-PR(25)2702024
Pellets of frozen material travelling into a magnetically confined fusion plasma are accelerated by the so-called pellet rocket effect. The non-uniform plasma heats the pellet ablation cloud asymmetrically, producing pressure-driven, rocket-like propulsion of the pellet. We present a semi-analytical model of this process by perturbing a spherica…
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UKAEA-CCFE-PR(25)2712024
We detail here a semi-analytical model for the pellet rocket effect, which describes the acceleration of pellets in a fusion plasma due to asymmetries in the heat flux reaching the pellet surface and the corresponding ablation rate. This effect was shown in experiments to significantly modify the pellet trajectory, and projections for reactor sc…
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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(25)2642023
Advances in edge and scrape-off layer diagnostics have shown that often the ion temperature is higher than the electron temperature in scrape-off layer filaments. We have therefore extended the STORM model beyond the cold ion limit commonly used, to include hot ion effects. We find that filaments are both faster and more coherent than in a cold …
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UKAEA-STEP-PR(25)242024
The UKAEA’s Spherical Tokamak for Energy Production (STEP) programme aims to demonstrate the ability of low aspect ratio tokamaks to generate net electricity from deuterium-tritium (DT) fusion. As STEP have selected REBCO coated conductor (CC) as the current carrier in most magnet systems, understanding how REBCO CC responds to the energetic p…
Showing 281 - 290 of 2581 UKAEA Paper Results