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UKAEA-STEP-PR(24)232024
Electron Bernstein waves (EBWs) are theorised to efficiently drive current in spherical tokamak power plants, e.g. Spherical Tokamak for Energy Production (STEP). At high temperatures (Te ≳4keV), relativistic effects can significantly impact wave propagation. This work presents relativistic calculations of EBW wave propagation, damping, and curre…
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UKAEA-CCFE-PR(26)4552024
The linear MHD peeling-ballooning stability analysis on the ELM-free phase of MAST Upgrade H-mode plasma is presented. In contrast to other similar discharges, #47018 is found to have significantly higher and wider pedestal during an ELM-free H-mode phase that lasts for approximately 80ms, which is made possible by the reduced core MHD mode acti…
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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)3692024
Plasma detachment in tokamaks is useful for reducing heat flux to the target. It involves interactions of the plasma with impurities and neutral particles, leading to significant losses of plasma power, momentum, and particles. Accurate mapping of plasma emissivity in the divertor and X-point region is essential for assessing the rel…
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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-CCFE-PR(25)3112024
2D electron density profiles obtained from coherence imaging spectroscopy in different MAST-U divertor conditions are compared. The data includes variations of strike point position, core electron density, and heating power. The improved performance of the long-legged divertors results in a lower electron density and particle flux at the target …
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UKAEA-CCFE-PR(25)3042024
A plasma scenario with negative triangularity (NT) shaping is achieved on MAST-U for the first time. While edge localized modes (ELMs) are eventually suppressed as the triangularity is decreased below δ ≲ −0.06, an extended period of H-mode operation with Type-III ELMs is sustained at less negative δ even through access to the second stabilit…
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UKAEA-CCFE-PR(24)2702024
Plasma turbulence on disparate spatial and temporal scales plays a key role in defining the level of confinement achievable in tokamaks, with the development of reduced numerical models for cross-scale turbulence effects informed by experimental measurements an essential step. MAST-U is a well-equipped facility having instruments to measure ion …
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UKAEA-STEP-PR(24)182024
This paper presents a comprehensive overview of the preliminary divertor design and plasma exhaust scenario for the reactor-class Spherical Tokamak for Energy Production (STEP) project. Due to the smaller size of the machine, with a major radius less than half that of most DEMO concepts, the current design features a double-null divertor geometr…
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UKAEA-STEP-PR(24)122024
Ensuring tritium fuel self-sufficiency while maintaining continuous and high specification fuel flow to the tokamak via a low tritium inventory and controllable fuel cycle is a significant challenge to the STEP plant design. Effective and high-quality fuelling and exhausting is required to sustain and control a stable plasma, whereas fuel suffic…
Showing 11 - 20 of 266 UKAEA Paper Results