N.Osborne K.Verhaegh M.D.Bowden T.Wijkamp N.Lonigro P.Ryan E.Pawelec B.Lipschultz V.Soukhanovskii T.Biggelaar
High resolution D2 Fulcher band spectroscopy was used in the MAST-U divertors during Super-X and elongated conventional divertor density ramps with D2 fuelling from the mid-plane high-field side. In the Super-X case (density ramp from Greenwald fraction 0.12 to 0.24), the upper divertor showed ground state rotational tempe…
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 PublishedShu Huang Ryan Kerr Samuel Murphy Mark R. Gilbert Jaime Marian
We present a numerical model to predict oxide scale growth on tungsten surfaces under exposure to oxygen at high temperatures. The model captures the formation of four thermodynamically-compatible oxide sublayers, WO2, WO2.72, WO2.9, and WO3, on top of the metal substrate. Oxide layer growth is simulated by tracking the oxide/oxide and oxide/metal …
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 PurchaseJ.F. Rivero-Rodriguez S. Sharapov K. McClements M. Garcia-Muñoz N. Crocker M. Dreval D. Dunai N. Fil M. Fitzgerald J. Galdon-Quiroga C. Michael D. Ryan L. Velarde the MAST-U Team
Due to their relatively higher Vbeam/VAlvén ratio, spherical tokamaks are ideal to investigate high-frequency modes such as Compressional Alfvén Eigenmodes (CAEs) and Global Alfvén Eigenmodes (GAEs), and so they have been previously studied in MAST [1, 2]. Besides, the recently installed scintillator-based Fast-Ion Loss …
PreprintL. Kogan D. Ryan S. Gibson J. Berkery S. Sabbagh T. Farley P. Ryan K. Verhaugh B. Kool T.A. Wijkamp R. Scannell R. Sarwar C. Wade the MAST-U team
The MAST-U spherical tokamak has extensive capabilities to produce and explore strongly shaped plasmas and alternative divertor configurations, especially the Super-X. Robust and accurate reconstructions of plasma equilibria are the foundation of many physics analyses, as well as being important intershot for informing operation of the tokamak. …
PreprintJW 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…
PreprintK. 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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