P. J. RyanS. D. ElmoreJ. R. HarrisonJ. LovellR. Stephen
A detailed description of the Langmuir probe system on MAST Upgrade is presented. The system features 850 tile embedded probes, and 40 bespoke electronic modules which each have the capability to drive and acquire data from up to 16 probes in a time multiplexed manner. The system provides spatio-temporal resolved measurements (1 cm and $\\\\sim$1 m…
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…
PreprintJ 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 PurchaseP.-Y. Li D. R. Hatch B. Chapman-Oplopoiou S. Saarelma C. M. Roach M. Kotschenreuther S. M. Mahajan the MAST Team
The results of a recent gyrokinetic analysis of turbulent transport driven by the electron temperature gradient (ETG) in the MAST pedestal are presented. During the inter-ELM period, the buildup rate of the electron density gradients is faster than that of the electron temperature gradients, possibly indicating the presence of an active electron th…
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…
PreprintD A Ryan R Martin N B Ayed L Kogan A Kirk the MAST Upgrade team
MAST Upgrade has just begun its second physics campaign. The set of magnetic probes used to diagnose the magnetic field and currents on MAST Upgrade are described, and their calibration procedures outlined including calculation of uncertainties. The arrays of installed instability diagnostics are described and the detection and diagnosis of a speci…
Preprint PublishedM. 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 PublishedS. Elmore A. J. Thornton R. Scannell A. Kirk the MAST Team
Understanding the plasma parameters that affect the scrape off layer (SOL) width is a key issue for future tokamaks as the power entering the SOL (of order 100 MW [1] in ITER) and the SOL width (of order millimetres [2]) determine the heat flux to the divertor surfaces. The Eich scaling [2] can be used to characterise the divertor heat flux prof…
Preprint PublishedFabio 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 PurchaseM Cecconello
Spherical tokamaks are key for the successful design of operating scenarios of future fusion reactors in the areas of divertor physics, neutral beam current drive and fast ion physics. MAST Upgrade, which has successfully concluded its first experimental campaign, was specifically designed to address the role of the radial gradient of the fast ion…
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