N. R. Walkden J. Harrison S. A. Silburn T. Farley S.S. Henderson A. Kirk F. Militello A.Thornton the MAST Team
Using high speed imaging of the divertor volume, the region close to the X-point in MAST is shown to be quiescent. This is confirmed by three different analysis techniques and the quiescent X-point region (QXR) spans from the separatrix to the N = 1.02 flux surface. Local reductions to the atomic density and effects associated with the camera vie…
Preprint PublishedA. Kirk A.J. Thornton J.R. Harrison F. Militello N.R. Walkden The MAST Team The EUROfusion MST1 Team
Clear filamentary structures are observed at the edge of tokamak plasmas. These filaments are ejected out radially and carry plasma in the far Scrape Off Layer (SOL) region, where they are responsible for producing most of the transport. A study has been performed of the characteristics of the filaments observed in L-mode plasma on MAST, using visi…
Preprint PublishedM. Valovič P.T. Lang A. Kirk W. Suttrop M. Cavedon G. Cseh M. Dunne L.R. Fischer L. Garzotti L. Guimarais G. Kocsis A. Mlynek B. Plőckl R. Scannell T. Szepesi G. Tardini A. Thornton E. Viezzer E. Wolfrum The ASDEX Upgrade team The EUROfusion MST1 team
The complete refuelling of the plasma density loss (pump-out) caused by mitigation of Edge Localised Modes (ELMs) is demonstrated on the ASDEX Upgrade tokamak. The plasma is refuelled by injection of frozen deuterium pellets and ELMs are mitigated by external resonant magnetic perturbations (RMPs). In this experiment relevant dimensionless paramete…
Preprint PublishedS. Elmore S.Y. Allan G. Fishpool A. Kirk A.J. Thornton N.R. Walkden J.R. Harrison The MAST Team
In future nuclear fusion reactors high heat load events, such as edge-localised modes (ELMs), can potentially damage divertor materials and release impurities into the main plasma, limiting plasma performance. The most difficult to handle are type I ELMs since they carry the largest fraction of energy from the plasma and therefore deposit the large…
Preprint PublishedA.J. Thornton G. Fishpool A. Kirk The MAST Team The EUROfusion MST1 Team
Filamentary transport across the scrape off layer is a key issue for the design and operation of future devices, such as ITER, DEMO and MAST-U, as it sets the power loadings to the divertor and first wall of the machine. Analysis has been performed on L mode filaments in MAST in order to gain an understanding of the spatial structure and attempt to…
Preprint PublishedE. Havlíčková J. Harrison B. Lipschultz G. Fishpool A. Kirk A. Thornton M. Wischmeier S. Elmore S. Allan
SOLPS simulations of MAST-U have been carried out to identify in more detail the physics and operational properties of novel divertor configurations such as Super-X divertor (SXD), in particular the physics of detachment. A well diagnosed L-mode discharge from MAST has been utilised to determine L-mode transport coefficients representative for MAST…
Preprint PublishedA. Kirk W. Suttrop I.T. Chapman Yueqiang Liu R. Scannell A.J. Thornton L. Barrera Orte P. Cahyna T. Eich R. Fischer C. Fuchs C. Ham J.R. Harrison MW. Jakubowski B. Kurzan S. Pamela M. Peterka D. Ryan S. Saarelma B. Sieglin M. Valovic M Willensdorfer MAST and ASDEX Upgrade Teams
Sustained Edge Localised Mode (ELM) mitigation has been achieved on MAST and AUG using RMPs with various toroidal mode numbers over a wide range of low to medium collisionality discharges. The ELM energy loss and peak heat loads at the divertor targets have been reduced. The ELM mitigation phase is typically associated with a drop in plasma density…
Preprint PublishedM. Valovic L. Garzotti C. Gurl A. Kirk D. Dunai A.R. Field I. Lupelli G. Naylor A. Thornton The MAST Team
The fuelling of plasmas by shallow frozen pellets with simultaneous mitigation of edge- localised modes (ELM) by external magnetic perturbation is demonstrated on the MAST tokamak. In these plasmas post-pellet particle loss is dominated by ELMs. It is shown that the size of post-pellet ELMs can be controlled by external magnetic perturbations. Post…
Preprint PublishedJ.C. Hillesheim F.I. Parra M. Barnes N.A. Crocker H. Meyer W.A. Peebles R. Scannell A. Thornton The MAST Team
Tokamak plasmas rotate even without external injection of momentum. A Doppler backscattering system installed at MAST has allowed this intrinsic rotation to be studied in Ohmic L-mode and Hmode plasmas, including the first observation of intrinsic rotation reversals in a spherical tokamak. Experimental results are compared to a novel 1D model, whic…
Preprint PublishedS. Elmore S.Y. Allan G. Fishpool A. Kirk M. Kocan P. Tamain A.J. Thornton The MAST Team
Edge-localised modes (ELMs) can carry significant fractions of their energy as far as main chamber plasma-facing components in divertor tokamaks. Since in future devices (e.g. ITER, DEMO) these energies could cause issues for material lifetime and impurity production, the energy and temperature of ions in ELMs needs to be investigated. In MAST, nov…
Preprint Published