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…
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 PurchaseO. Myatra D. Moulton B. Dudson S. Newton B. Lipschultz K. Verhaegh A. Fil
The role of ion-molecule elastic collisions (specifically D+−D2 collisions) in strongly detached divertor conditions has been studied in the MAST-U Super-X configuration using SOLPS-ITER. Two strongly detached steady state solutions, one obtained through a main-ion (D2) fuelling scan and the other through an impurity (N) seeding scan at fixed fue…
PreprintR. T. Osawa D. Moulton S. L. Newton S. Henderson B. Lipschultz A. Hudoba
To mitigate the issue of plasma exhaust in reactor scale tight aspect ratio tokamaks such as STEP (Spherical Tokamak for Energy Production), a double-null (DN) configuration is thought to be advantageous over a single-null (SN) configuration. However, practical control of the plasma vertical stability will likely lead to an oscillation around th…
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 PublishedC Cowley A Q Kuang D Moulton J D Lore J Canik M Umansky M Wigram S Ballinger B Lipschultz
The design and understanding of alternative divertor configurations may be crucial for achieving acceptable steady-state heat and particle material loads for magnetic confinement fusion reactors. Multiple x-point alternative divertor geometries such as Snowflakes and Xpoint targets have great potential in reducing power loads, but have not yet b…
Preprint PublishedC. Cowley Bruce Lipschultz David Moulton Ben Dudson
As tokamak research moves to reactor conditions, the control of a stable, optimally-detached divertor plasma has become increasingly relevant. Simple predictions of such detachment control have been performed previously using the Detachment Location Sensitivity (DLS) model of detachment. In this study the DLS model is extended and combined with SOL…
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…
PreprintA. Fil B. Lipschultz D. Moulton A. Thornton B. D. Dudson O. Myatra K. Verhaegh the EUROFusion WPTE team
MAST-U has recently started operating with a Super-X divertor, designed to increase total flux expansion and neutral trapping, both predicted through simple analytic models and SOLPS calculations to reduce the plasma and impurity density detachment thresholds. In this study, utilising the SOLPS-ITER code, we are quantifying the possible gain allowe…
Preprint Published