William Iliffe Kirk Adams Nianhua Peng Greg Brittles Rod Bateman Aidan Reilly Chris Grovenor Susannah Speller
Commercial fusion power plants will require strong magnetic fields that can only be achieved using state-of-the-art high temperature superconductors in the form of REBCO coated conductors. In operation in a fusion machine, the magnet windings will be exposed to fast neutrons that are known to adversely affect the superconducting properties of REBCO…
PreprintS. 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 PublishedS. Saarelma J.W. Connor P. Bilkova P. Bohm A.R. Field L. Frassinetti R. Fridstrom A. Kirk JET Contributors*
The neutral ionisation model proposed by R J Groebner et al. (Phys Plasmas 9 2134 (2002)) to determine the plasma density profile in the H-mode pedestal, extended to include charge exchange processes in the pedestal stimulated by the ideas of Mahdavi et al. ((Phys Plasmas 10 3984 (2003)). The model is then tested a…
PreprintC. Vincent S. Allan G. Naylor R. Stephen S. Bray A. Thornton A. Kirk
Neutron flux measurements are important in fusion devices for both safety requirements and physics studies. A newsystem has been built for the Mega Amp Spherical Tokamak Upgrade (MAST Upgrade) that provides neutron count,DC and Campbell mode measurements for a 1μsperiod at 1 MHz. The acquisition system uses a Red Pitaya board tosample current from…
Preprint PurchaseS.F. Smith S.J.P. Pamela A. Fil M. Hölzl G.T.A. Huijsmans A. Kirk D. Moulton O. Myatra A.J. Thornton H.R. Wilson
The high heat fluxes to the divertor during edge localised mode (ELM) instabilities have to be reduced for a sustainable future tokamak reactor. A solution to reduce the heat fluxes could be the Super-X divertor, this divertor configuration will be tested on MAST-U. ELM simulations for MAST-U Super-X tokamak plasmas have been obtained, using JOR…
PreprintJ. R. Harrison T. Farley G. M. Fishpool A. Kirk B. Lipschultz J. Lovell F. Militello D. Moulton P. Ryan R. Scannell A. J. Thornton K. Verhaegh L. Xiang
The benefits of an optimised Super-X divertor configuration in mitigating the steady-state power and particle fluxes to the surfaces of the MAST Upgrade divertor have been quantified by performing a detailed comparison with a conventional divertor for the first time. In otherwise identical plasmas with conventional and Super-X divertor configu…
PreprintS. Kirk K. Keogh
The maintenance and decommissioning of nuclear reactors requires the rapid cutting and welding of thick-walled pipework, to which laser processing is highly suited. However, the large size and stand-off of current laser heads precludes their use in space constrained areas and incorporation into in-bore processing tools. To address this, novel minia…
Preprint PublishedJ. Leland S. Elmore A. Kirk H. v/d Meiden. J. Scholten S. Allan J. W. Bradley
Measurements made using flush-mounted Langmuir probes (FMPs) in tokamaks are difficult to interpret when operating at grazing angles of magnetic field incidence due to the effects of sheath expansion on the probe collection area. The super-X divertor on the upgraded Mega Ampere Spherical Tokamak (MAST-U) will have very shallow angles of magnetic fi…
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.A. Sabbagh J.W. Berkery A. Kirk Y.S. Park J.H. Ahn J.M. Bialek Y. Jiang J.D. Riquezes J.G. Bak K. Erickson A.H. Glasser C. Ham J. Hollocombe J. Kim J. Ko W.H. Ko L. Kogan J.H. Lee A. Thornton S.W. Yoon Z.R. Wang
Disruption prediction and avoidance is critical in ITER and reactor-scale tokamaks to maintain steady plasma operation and to avoid damage to device components. The present status and results from the physics-based disruption event characterization and forecasting (DECAF) research effort are shown for multiple tokamak devices. Present analysis of K…
Preprint Published