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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)322023
In future demonstration fusion power plants, plasma facing components will face high steady state and ultra-high transient heat loads from the plasma. Introducing low thermal conductivity features to the component can reduce the peak temperatures seen by the coolant pipe, but at the trade-off of a loss of steady-state performance. Producing low-con…
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UKAEA-STEP-PR(25)312024
A strategy to prevent concentrated deposition of the exhaust power in a fusion device is to seed a localised ‘divertor’ region with impurity gas, which is chosen to radiate predominantly at the cooler electron temperatures associated with the plasma edge. If this impurity travels upstream to the main confined plasma, it can significantly impact…
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UKAEA-STEP-PR(25)302025
The effects of a poloidally localized bulge at outer midplane is investigated with regards to the stability of ideal MHD peeling-ballooning modes and n = ∞ ballooning modes. The effect of the bulge is that the n = ∞ ballooning mode stability at the bottom of the H-mode pedestal is significantly degraded, while the peeling-ballooning mode sta…
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2025
AC losses in the high temperature superconducting (HTS) toroidal field (TF) magnets of the STEP tokamak are analysed, focusing on the transient electromagnetic response of the centre column to the charging and discharging of the central solenoid (CS) and poloidal field (PF) magnets during a plasma initiation scenario. An innovative H-H…
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UKAEA-STEP-PR(25)292025
Systems models and associated cost analyses are widely used within the fusion community to analyse tokamak designs, from prototype and demonstrator machines to potential commercial fusion power plants. To ensure the design programmes of fusion prototype/demonstrator power plants deliver a cost optimised design (within existing uncertainty limita…
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UKAEA-STEP-CP(25)012022
A key aspect in the design of a spherical tokamak reactor is the optimisation of the plasma equilibrium, together with a compatible divertor configuration and the corresponding poloidal field system. This is a complex multi-disciplinary problem, integrating plasma physics and engineering in order to satisfy a multitude of often conflicting requi…
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UKAEA-STEP-PR(25)282023
Generation of Runaway Electrons (REs) during plasma disruptions, and their impact on plasma facing components, is of great concern for ITER and future reactors based on the tokamak concept. Current STEP (Spherical Tokamak for Energy Production) concept design flat top operating point features a plasma current higher than 20 MA and thus any plasm…
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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…
Showing 1 - 10 of 72 UKAEA Paper Results