M. 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…
PreprintP. 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…
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…
PreprintH. G. Dudding F. J. Casson D. Dickinson B. Patel C. M. Roach E. A. Belli G. M. Staebler
A new quasilinear saturation model SAT3 has been developed for the purpose of calculating radial turbulent fluxes in the core of tokamak plasmas. The new model is shown to be able to better recreate the isotope mass dependence of nonlinear gyrokinetic fluxes compared to contemporary quasilinear models, including SAT2 [1], whilst performing at least…
Preprint PublishedB.S. Patel D. Dickinson C.M. Roach H.R. Wilson
Spherical tokamaks (STs) have been shown to possess properties desirable for a fusion power plant such as achieving high plasma β and having increased vertical stability. To understand their confinement properties in a reactor relevant regime a 1GW fusion power spherical tokamak plasma equilibrium was analysed using linear gyrokinetics to deter…
Preprint PublishedG. M. Staebler E. Belli J. Candy J. E. Kinsey H. Dudding B. Patel
The verification and calibration of a new quasi-linear transport model with a large database of gyrokinetic turbulence simulations is presented in this paper. In a previous paper [1], a model for the saturated spectrum of electric potential fluctuations was developed based on the properties of the non-linear 3D spectrum. In this paper, a modifi…
PreprintG. M. Staebler J. Candy E. Belli J. E. Kinsey N. Bonanomi B. Patel
The findings of an investigation into the properties of the three dimensional (3D) saturated fluctuation intensity of the electric potential in gyrokinetic turbulence simulations is presented. Scans in flux surface elongation and Shafranov shift are used to isolate the tokamak geometric dependencies. The potential intensity required in order to …
Preprint PublishedB. Patel C. Challis D. Dickinson L. Garzotti F. Koechl C. Roach G. Staebler H. Wilson
Spherical Tokamaks (STs) could provide a route towards a compact fusion reactor due to advantageous properties such as high plasma beta. A GW-scale ST plasma is explored where Q=10 and R=2.5m. In this design 110 MW of NBI is needed to provide 9 MA of noninductive current, where the remaining 12 MA is pressure driven. To penetrate into the core a 1 …
Preprint PublishedStuart I. Muldrew Hanni Lux Tim C. Hender Bhavin Patel Peter J. Knight Garry M. Voss Howard R. Wilson
Spherical Tokamaks offer a number of potential advantages for a future fusion power plant. They have a high ratio of thermal to magnetic field pressure (beta) and strong flows, either of which could result in reduced turbulence. Fewer Toroidal Field (TF) coils and a different geometry offers the potential for new methods of remote maintenance …
Preprint Published