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…
PreprintG. McArdle M. Kochan C. Vincent L. Swaidani H. Anand D. Eldon W. Wehner G. Derks S. Elmore B. Kool K. Verhaegh R. Sarwar B. Parry R. Scannell J. Harrison A. Thornton A. Kirk G. Cunningham the MAST Upgrade Team
The real time plasma control system for the MAST Upgrade tokamak has been substantially redeveloped from its original MAST incarnation with a new architecture that aims to manage complexity whilst maximising flexibility. It provides modular layers of functionality and supports the implementation of virtual actuators to aggregate, arbitrate and rout…
PreprintK. Verhaegh B. Lipschultz J.R. Harrison F. Federici D. Moulton N. Lonigro M. O'Mullane N. Osborne P. Ryan T. Wijkamp B. Kool C. Theiler A. Thornton
First quantitative analysis of the detachment processes in the MAST Upgrade Super-X divertor show an unprecedented impact of plasma-molecular interactions involving molecular ions, resulting in strong ion sinks, leading to a reduction of ion target flux. This starts to occur as the ionisation source detaches from the target, leading to a build-up o…
PreprintFabio Federici Matthew L. Reinke Bruce Lipschultz Andrew J. Thornton James R. Harrison Jack J. Lovell Peter Ryan Matthias Bernert Hendrik F. Meyer the MAST Upgrade team
A prototype infrared video bolometer (IRVB) was succesfully deployed in MAST-U, the first deployment of such a diagnostic in spherical tokamaks. The IRVB was designed to study the radiation around the x-point and has the potential to return emissivity profiles of unprecedented spatial resolution. The system was fully characterised prior installatio…
Preprint PurchaseP. 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…
PreprintK. Verhaegh A.C. Williams D. Moulton B. Lipschultz B.P. Duval O. Février A. Fil J. R. Harrison N. Osborne H. Reimerdes C. Theiler
Divertor detachment requires plasma-neutral interactions which dissipate momentum, power and particles simultaneously. Plasma-molecular interactions can result in molecular ions which react with the plasma. This can contribute to detachment through molecular activated recombination (MAR) and molecular activated dissociation (MAD), both of which cre…
Preprint PublishedJW Berkery SA Sabbagh L Kogan S Gibson D Ryan V Zamkovska J Butt J Harrison S Henderson MAST-U team
The MAST-U fusion plasma research device, the upgrade to the Mega Amp Spherical Tokamak, has recently completed its first campaign of physics operation. MAST-U operated with Ohmic, or one or two neutral beams for heating, at 400-800 kA plasma current, in conventional or “SuperX” divertor configurations. Equilibrium reconstructions provide key p…
PreprintNick Walkden Fabio Riva James Harrison Fulvio Militello Tom Farley John Omotani
Fusion power plant designs based on magnetic confinement, such as the tokamak design, offer a promising route to sustainable fusion power but require robust exhaust solutions capable of tolerating intense heat and particle fluxes from the plasma to material surfaces. Turbulent plasma transport in the divertor volume – the region where the plasma-…
Preprint PublishedH. J. Sun R. J. Goldston A. Huber X. Q. Xu J. Flanagan D. C. McDonald E. de la Luna M. Maslov J. R. Harrison F. Militello J. Fessey S. Cramp JET Contributors
A study of a dataset of JET H-mode plasma with the Be/W ITER-like wall (JET-ILW) shows that reaching the edge MHD ballooning limit leads to confinement degradation. However, unlike JET plasmas with a carbon wall (JET-C), the JET-ILW plasmas stay in a marginal dithering phase for a relatively long period, associated with a higher (20%) H-mode den…
Preprint PublishedK. Verhaegh B. Lipschultz J.R. Harrison N. Osborne A. Williams P Ryan J. Allcock J. Clark F. Federici B. Kool T. Wijkamp A. Fil D. Moulton O. Myatra A. Thornton T.O.S.J. Bosman C. Bowman B. Duval S. Henderson R. Scannell the MAST Upgrade team the EuroFusion MST1 team
In this paper we a first qualitative analysis of the atomic and molecular processes at play during detachment in the MAST-U Super-X divertor, using divertor spectroscopy data. Our analysis indicates a wide operational regime of detachment of the MAST-U super-X divertor, which can be roughly separated in four phases: 1) The ionisation front detac…
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