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UKAEA-STEP-PR(26)022025
Alternative Divertor Configurations (ADCs) often make use of high total flux expansion (fR) and connection length (L∥) to improve the access to and the controllability of detachment, a regime vitally important for reactor-class tokamaks such as the Spherical Tokamak for Energy Production (STEP). However, there has been little effort in assessi…
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UKAEA-CCFE-PR(26)4572024
The Yacora solver has been used to generate two novel molecular rate databases for use in SOLPS-ITER. The reduced Yacora database utilises updated cross-sectional data, whilst the full Yacora database includes the same updated cross-sectional data in addition to the inclusion of vibrational reactions such as off-diagonal vibrational electron-impact…
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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-RACE-PR(25)032024
When using deep reinforcement learning (DRL) to perform multi-robot exploration in unknown environments, the training model may produce actions that lead to unpredictable system behaviours due to the complexity and unpredictability of the surroundings. Therefore, ensuring safe exploration with DRL becomes critical. To tackle this issue, we propo…
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UKAEA-STEP-PR(24)142024
This theme issue collects together papers summarising the conceptual design of the Spherical Tokamak for Energy Production (STEP). In 2019, the UK government funded the first design stages of a prototype fusion powerplant based on a compact toroidal geometry, called STEP. The primary technical aims of STEP are to produce net energy, to be self-s…
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UKAEA-CCFE-CP(26)382023
A pedestal density prediction model based on combining the transport in the pedestal to an ionization model is used to predict the density profile of tokamak H-mode pedestals. The transport model combines stiff ETG turbulence, KBM turbulence based on critical pressure gradient and a small neoclassical transport. The ionization aspect of the mode…
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UKAEA-RACE-CP(23)062023
Sim-and-real training is a promising alternative to sim-to-real training for robot manipulations. However, the current sim-and-real training is neither efficient, i.e., slow convergence to the optimal policy, nor effective, i.e., sizeable real-world robot data. Given limited time and hardware budgets, the performance of sim-and-real training is …
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UKAEA-CCFE-PR(23)1672023
A nonlinear 4-dimensional drift island theory derived in (Imada et al 2019 Nucl. Fusion 59 046016 and references therein) provides qualitative predictions of the plasma response to a stationary neoclassical tearing mode (NTM) magnetic island in a low beta, large aspect ratio tokamak plasma. (Dudkovskaia et al 2021 Plasma Phys. Control. Fusion 63 05…
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UKAEA-CCFE-PR(23)1522023
This article presents an in-depth study of the sequence of events leading to density limit disruption in J-TEXT tokamak plasmas, with an emphasis on boudary turbulent transport and the high-field-side high-density (HFSHD) front. These phenomena were extensively investigated by using Langmuir probe and Polarimeter-interferometer diagnostics. The res…
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UKAEA-CCFE-PR(23)012022
The design and understanding of alternative divertor configurations may be crucial for achieving acceptable steady-state heat and particle material loads for magnetic confinement fusion reactors. Multiple x-point alternative divertor geometries such as Snowflakes and Xpoint targets have great potential in reducing power loads, but have not yet b…
Showing 1 - 10 of 118 UKAEA Paper Results