J. R. Harrison C. Bowman J. G. Clark A. Kirk B. S. Patel P. Ryan R. Scannell A. J. Thornton K. Verhaegh
The integration of good core and edge/pedestal confinement with strong dissipation of heat and particles in the divertors is a significant challenge for the development of fusion energy. Alternative divertor configurations offer potential advantages by broadening the operational space where a device can operate with detached divertors and acce…
PreprintD. Kennedy M. Giacomin B. Patel C. M. Roach D. Dickinson
The importance of parallel magnetic field perturbations in gyrokinetic simulations of electromagnetic instabilities and turbulence at mid-radius in the burning plasma phase of the conceptual high-β, reactor-scale, tight-aspect-ratio tokamak STEP is discussed. Previous studies have revealed the presence of unstable hybrid kinetic ballooning modes (…
PreprintM. Mantsinen P. Jacquet E. Lerche D. Gallart K. Kirov P. Mantica D. Taylor D. Van Eester M. Baruzzo I. Carvalho C. Challis E. Delabie E. De La Luna R. Dumont P. Dumortier J. Eriksson D. Frigione J. Garcia L. Garzotti C. Giroud R. Henriques J. Hobirk A. Kappatou Y. Kazakov D. Keeling D. King V. Kiptily M. Lenholm P. Lomas C. Lowry C. Maggi J. Mailloux M. Maslov S. Menmuir I. Monakhov R.B. Morales C. Noble M. Nocente A. Patel G. Pucella C. Reux D. Rigamonti F. Rimini A. Sheikh S. Silburn P. Siren E. Solano Z. Stancar M. Tardochi
The reference ion cyclotron resonance frequency (ICRF) heating schemes for ITER deuterium-tritium (D-T) plasmas at the full magnetic field of 5.3 T are second harmonic heating of tritium and 3He minority heating. The wave-particle resonance location for these schemes coincide and are central at a wave frequency of 53 MHz at 5.3T [1]. Experiments ha…
PublishedD. Batty L. Manes A. West M. Patel I. Caliskanelli P. Paoletti
In the nuclear industry, the need for improved reliability in current and future technology hinders the deployment of autonomous robotic systems. The following research aims to develop a method of reliably mapping a large environment and abstracting the map into a sparse node graph to create a more efficient data form. The proposed data form all…
PurchaseJ W Berkery S A Sabbagh C Ham V Zamkovska J Butt J Riquezes M Tobin S Henderson L Kogan B Patel R Scannell E Trier B LeBlanc
Fusion power output from spherical tokamaks would benefit from increased confined plasma density, but there exists a limit on the density before confinement is lost and the plasma current is disrupted. This density limit has long been characterized by a simple, global Greenwald limit proportional to the plasma current and inversely proportional …
Preprint PurchaseD. Kennedy M. Giacomin B. S. Patel W. A. Hornsby D. Dickinson C. M. Roach
We present herein the results of a linear gyrokinetic analysis of electromagnetic microinstabilites in the conceptual high−β, reactor-scale, tight-aspect-ratio tokamak STEP (Spherical Tokamak for Energy Production, https://step.ukaea.uk). We examine a range of flux surfaces between the deep core and the pedestal top for the two candidate flat…
Preprint PublishedM. Giacomin D. Kennedy C. J. Ajay D. Dickinson B. S. Patel C. M. Roach
In this work, we present the results of first-of-their-kind nonlinear local gyrokinetic simulations of electromagnetic turbulence at mid-radius in the burning plasma phase of the conceptual high-β, reactor-scale, tight-aspect-ratio tokamak STEP (Spherical Tokamak for Energy Production). A prior linear analysis in D.Kennedy et al. submitted to Nucl…
PreprintM. Giacomin D. Dickinson D. Kennedy B. Patel C. M. Roach
Linear and nonlinear gyrokinetic simulations are performed in experimentally relevant scenarios built from a MAST case where a microtearing mode instability dominates at ion Larmor radius scale. This collisional microtearing mode instability appears only when a vel…
Preprint PublishedP. Ollus S. Allan J.R. Harrison A. Jackson T. Kurki-Suonio K.G. McClements C.A. Michael D. Moulton B.S. Patel M. Robson A. Snicker J. Varje C. Vincent the MAST-U team the EUROfusion WPTE team
Predictions of the impact of charge-exchange (CX) reactions on beam ions in the MAST Upgrade spherical tokamak have been compared to measurements carried out with a fission chamber (neutron fluxes) and a Fast Ion Deuterium-Alpha (FIDA) diagnostic. A simple model was developed to reconstruct the outer-midplane neutral density based on Thomson sca…
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…
Preprint