JW 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…
PreprintK. Verhaegh B. Lipschultz J.R. Harrison B.P. Duval A. Fil D.S. Gahle D. Moulton O. Myatra A. Perek S. Henderson C. Theiler A. Thornton M. Wensing
This paper shows experimental results from the TCV tokamak that indicate plasma-molecule interactions involving D+2 and possibly D− play an important role as sinks of energy (through hydrogenic radiation as well as dissociation) and particles during divertor detachment if low target temperatures (< 3 eV) are achieved. Bot…
Preprint PublishedM. Knolker T. Osborne E. Belli S. Henderson A. Kirk L. Kogan S. Saarelma P. B. Snyder
In preparation for the upcoming MAST-U campaign, pedestal stability of spherical tokamaks is revisited by investigating standard H-mode discharges on MAST. As a step beyond previous studies, both ion and electron profiles are used for obtaining equilibria and a diverse set of pedestals is evaluated. Stability analysis with the ELITE and CGYRO codes…
Preprint PublishedS. S. Henderson M. Bernert C. Giroud D. Brida M. Cavedon P. David R. Dux J. R. Harrison A. Huber A. Kallenbach J. Karhunen B. Lomanowski G. Matthews A. Meigs R. A. Pitts F. Reimold M. L. Reinke S. Silburn N. Vianello S. Wiesen M. Wischmeier
While current tokamak experiments are beginning to utilise real-time feedback control systems to manage the plasma exhaust, future tokamaks still require validation of theoretical models used to predict the threshold impurity concentration required to facilitate stationary divertor operation. This work exploits new spectroscopic measurements of …
Preprint PublishedT. Farley N. R. Walkden F. Militello M. Sanna J. Young S. S. Silburn J. Harrison L. Kogan I. Lupelli S. S. Henderson A. Kirk J.W. Bradley
A new inversion technique is presented for the identification of plasma filaments in wide-angle visible camera data. Direct inversion of camera data onto a field aligned basis is a poorly conditioned problem which is overcome by breaking the analysis into a `psuedo-inversion’ step followed by a `point spread function correction’ step. Camera …
Preprint PublishedS. S. Henderson M. Bernert S. Brezinsek M. Carr M. Cavedon R. Dux D. S. Gahle J. Harrison B. Lipschultz B. Lomanowski A. Meigs M. O’Mullane F. Reimold M. L. Reinke S. Wiesen the EUROfusion MST1 team the ASDEX Upgrade team JET contributors
Reducing the plasma power exhaust impacting on plasma facing components during steady state operation is one of the major design issues in future tokamaks such as ITER. Impurity seeding, e.g. with N, is one method of achieving this and has been used for a long time in tokamak research [1]. In this work we exploit a recently developed spectroscopic …
Preprint PublishedM. Carr A. Meakins S. Silburn J. Karhunen M. Bernert C. Bowman A. Callarelli P. Carvalho C. Giroud J. Harrison S. Henderson A. Huber B. Lipschultz T. Lunt D. Moulton F. Reimold ASDEX Upgrade team JET contributors MAST-Upgrade team the EUROfusion MST1 Team
Ray-tracing techniques are applied to divertor filtered imaging, a diagnostic that has long been plagued by polluting reflected light features in metal walled fusion machines. A physically realistic surface reflection model is developed from a Cook-Torrence microfacet BRDF model. Camera calibration images of in-vessel point lights at JET are use…
Preprint PublishedJames Harrison C. Theiler B. Lipschultz A. Perek R. Maurizio B. Linehan W. A. J. Vijvers B. P. Duval B. Labit U. Sheikh K. Verhaegh S. Henderson A. Karpushov O. Fevrier H. de Oliviera H. Reimerdes A. Merle X. Feng the TCV team and the EUROfusion MST1 team
Recent experiments on TCV have made significant progress toward partial detachment of the outer divertor in neutral beam heated H-mode plasmas. The heating power required to enter H-mode was measured in a range of divertor configurations, finding that, in the vicinity of the PL-H/ne curve, the threshold power is largely independent of the poloidal …
Preprint PublishedMichael Komm Stuart Henderson Sarah Elmore COMPASS team EUROfusion MST1 team
Partial detachment is the desired regime for the baseline burning plasma scenario in ITER and next-step devices, as it allows to disspate the majority of the energy carried by charged particles through the scrape-off-layer (SOL) and thus avoids localised heat flux deposition in the divertor region. The COMPASS tokamak is equipped with an open diver…
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