James H.P. Rice Jianzhao Geng Rodney A. Badcock Dominic A. Moseley Steven Wray Heng Zhang
The application of dc magnetic field to a 2G high temperature superconducting (HTS) tape can reduce the critical current Ic of the tape, without driving the material normal. This property can be used in the development of HTS switching elements through so-called Jc(B) switching. The design of a dc magnetic field switch is reported, in both singl…
PreprintB. Din A. I. Blair F. Schoofs D. P. Hampshire
Understanding the properties of grain boundaries in polycrystalline superconductors is essential for optimizing their critical current density. Here, we provide computational simulations of 2D Josephson junctions (JJs) in low magnetic fields using time–dependent Ginzburg–Landau theory, since they can be considered a proxy for a grain boundar…
PreprintJ. Mitchell A. Parrot F. E. Eriksson F. Casson O. Bardsley M. Lennholm H. Meyer S. Aleiferis
In this paper we present optimized actuator trajectories, evolving in time and space, of non-inductive ramp-up scenarios for the Spherical Tokamak for Energy Production (STEP). These trajectories are computed by solving a non-linear, multi-objective, constrained, finite-time optimal control problem. A method unique to STEP ramp-up studies that prov…
Preprint PublishedHelen Brooks Andrew Davis
To support the design of fusion reactors for energy production, there is an urgent need to develop highly-scalable multi-physics software tools capable of modelling critical tokamak components as a single cohesive whole. Although some loosely-coupled physics tools do exist, these lack fidelity and will fundamentally fail to capture any closed-lo…
Preprint PublishedK. G. McClements M. Fitzgerald H. J. C. Oliver A. P. Prokopyszyn
The UK has launched a programme to build a prototype fusion power plant, the Spherical Tokamak for Energy Production (STEP), by 2040. It is intended that the STEP prototype will generate fusion power of the order of 1 GW and net electrical power of the order of 100 MW. Plasma scenarios that could be compatible with these design requirements and wit…
PreprintT. Wilson S.J. Freethy M. Henderson A Köhn-Seeman I. Konoplev S. Saarelma D. Speirs R.G.L. Vann the STEP team
The UK’s Spherical Tokamak for Energy Production (STEP) reactor design program is now exclusively investigating concepts using microwave-based heating and current drive (HCD) systems. Electron Bernstein Wave (EBW) HCD is a relatively immature technology compared to Electron Cyclotron (EC) HCD but is of interest due to the promise of high current…
PreprintGuoliang Xia T.C. Hender Yueqiang Liu E. Trier
The Spherical Tokamak for Energy Production (STEP) is a UKAEA program that aims to deliver a prototype fusion energy plant and a path to commercial viability of fusion [1]. The low aspect ratio spherical tokamak is attractive because of its potential to achieve high normalized beta βN operation, and the fusion power ~β…
PreprintWilliam Iliffe Kirk Adams Nianhua Peng Greg Brittles Rod Bateman Aidan Reilly Chris Grovenor Susannah Speller
Commercial fusion power plants will require strong magnetic fields that can only be achieved using state-of-the-art high temperature superconductors in the form of REBCO coated conductors. In operation in a fusion machine, the magnet windings will be exposed to fast neutrons that are known to adversely affect the superconducting properties of RE…
Preprint PublishedJulita Inca Andrew Davis Aleksander Dubas
Preconditioners are meant to improve both, the efficiency and robustness of iterative techniques while solving very large linear systems on a Krylov subspace. However, determining which preconditioner is suitable to be applied on a certain multiphysic simulation requires a combination of knowledge of preconditioning matrices techniques, types of ma…
PreprintJ Teah S Wray
Cryogenics are widely used in tokamak fusion reactors in three main areas. Firstly, to provide cooling to superconducting magnets for plasma confinement. Secondly, to provide the required level of vacuum in the plasma vessel through cryogenic vacuum technology. Thirdly, as part of the fusion fuel cycle, including matter injection, typically…
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