J.F. Rivero-Rodriguez J. Galdon-Quiroga J. Dominguez-Palacios M. Garcia-Muñoz D. Garcia-Vallejo J. Gonzalez-Martin K. McClements L. Sanchis K. Sarkimaki A. Snicker Y. Todo L. Velarde E. Viezzer
Observations of enhanced fast-ion losses during edge localized modes (ELMs) have been reported in the ASDEX Upgrade tokamak, revealing losses above the injection energy. This suggests that fast ions can be accelerated and lost by the ELMs. Recent analysis delves into the analysis of the ELM-induced losses, suggesting that the fast ions are los…
Preprint PublishedJ 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…
PreprintA.N. Petrov S. Wray K. Zarebski T. Stroud J. Acres T. Owoeye M. Cannon F. Christie T. Jackson V. Laksharam S. Stewart R. Griffiths N. Brewer K. Rochford S. Gribben
The work presented in this paper is an integrated time-dependent model, describing the power demands of the major tokamak components (magnets, cryogenics, heating and current drive, etc.), as well as the power generated. The physics are implemented in OpenModelica and make use of a Python API (Application Programming Interface) to collect inputs, r…
PreprintR. T. Osawa D. Moulton S. L. Newton S. Henderson B. Lipschultz A. Hudoba
To mitigate the issue of plasma exhaust in reactor scale tight aspect ratio tokamaks such as STEP (Spherical Tokamak for Energy Production), a double-null (DN) configuration is thought to be advantageous over a single-null (SN) configuration. However, practical control of the plasma vertical stability will likely lead to an oscillation around th…
PreprintS. Merriman J. Abraham J. Bailey J. Billingsley B. Edwards J. Hagues D. León Hernández N. Mantel N. Otway A. Saigiridhari S. Sherwood P. Ting J. Fradera P. Andrés A. Bernad D. Catalán S. Haouala S. Sádaba B. Echeveste S. Ha
The UK Spherical Tokamak for Energy Production (STEP) program is currently progressing the conceptual engineering design of a Spherical Tokamak-based fusion reactor. The program includes a project concerned with design of the reactor breeding blanket. The objective of this work was to develop a low fidelity, integrated simulation approach to sup…
PreprintDaniel Kennedy Bhavin S Patel Colin M Roach
Microinstabilities often result in turbulence that influences energy confinement in tokamak discharges. One such microinstability, of particular importance to the design of next-generation spherical tokamaks (STs) such as STEP [1], is the microtearing mode (MTM), a tearing-parity mode centred on high-order rational surfaces. MTMs are short-wavel…
PreprintR. Scannell the MAST Upgrade EUROfusion Tokamak Exploitation Teams
MAST Upgrade (MAST-U) is a new low aspect ratio device (R/a = 0.85/0.65 ~ 1.3) based on the MAST tokamak that started plasma operations in October 2020. It has substantial new capabilities compared with the original MAST device, with 19 new poloidal field coils (14 of which are within the vacuum vessel) and new, closed, up-down symmetric diverto…
PreprintHendrik Meyer the STEP Plasma Control Heating & Current Drive Team
With steady progress on ITER project and the design of DEMO, the international community is now entering an era in which fusion power on the grid could become a reality within the next 20 – 30 years. In this environment the UK has started the ambitious Spherical Tokamak for Energy Production (STEP) programme, aiming to develop a compact protot…
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…
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…
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