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Macroscopic stability of high β MAST plasmas

Chapman, I T; Cooper, W.A.; Graves, J.P.; Gryaznevich, M P; Hastie, R.J.; Hender, T.C.; Howell, D F; Hua, M.-D.; Huysmans, G.; Keeling, D; Liu, Y Q; Meyer, H; Michael, Clive; Pinches, S D; Saarelma, S.; Sabbagh, S.A.; MAST Team, The

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The high-beta capability of the spherical tokamak, coupled with a suite of world-leading diagnostics on MAST, has facilitated significant improvements in the understanding of performance-limiting core instabilities in high performance plasmas. For instance, the newly installed motional Stark effect diagnostic, with radial resolution <25 mm, has enabled detailed study of saturated long-lived modes in hybrid scenarios. Similarly, the upgraded Thomson scattering system, with radial resolution <10...[Show more]

dc.contributor.authorChapman, I T
dc.contributor.authorCooper, W.A.
dc.contributor.authorGraves, J.P.
dc.contributor.authorGryaznevich, M P
dc.contributor.authorHastie, R.J.
dc.contributor.authorHender, T.C.
dc.contributor.authorHowell, D F
dc.contributor.authorHua, M.-D.
dc.contributor.authorHuysmans, G.
dc.contributor.authorKeeling, D
dc.contributor.authorLiu, Y Q
dc.contributor.authorMeyer, H
dc.contributor.authorMichael, Clive
dc.contributor.authorPinches, S D
dc.contributor.authorSaarelma, S.
dc.contributor.authorSabbagh, S.A.
dc.contributor.authorMAST Team, The
dc.date.accessioned2015-12-08T22:40:31Z
dc.identifier.issn0029-5515
dc.identifier.urihttp://hdl.handle.net/1885/36527
dc.description.abstractThe high-beta capability of the spherical tokamak, coupled with a suite of world-leading diagnostics on MAST, has facilitated significant improvements in the understanding of performance-limiting core instabilities in high performance plasmas. For instance, the newly installed motional Stark effect diagnostic, with radial resolution <25 mm, has enabled detailed study of saturated long-lived modes in hybrid scenarios. Similarly, the upgraded Thomson scattering system, with radial resolution <10 mm and the possibility of temporal resolution of 1 νs, has allowed detailed analysis of the density and temperature profiles during transient activity in the plasma, such as at a sawtooth crash. High resolution charge exchange recombination spectroscopy provided measurement of rotation braking induced by both applied magnetic fields and by magnetohydrodynamic (MHD) instabilities, allowing tests of neoclassical toroidal viscosity theory predictions. Finally, MAST is also equipped with internal and external coils that allow non-axisymmetric fields to be applied for active MHD spectroscopy of instabilities near the no-wall beta limit. MAST has been able to operate above the pressure at which the resonant field amplification is observed to strongly increase. In order to access such high pressures, the resistive wall mode must be damped, and so numerical modelling has focused on assessing the kinetic damping of the mode and its nonlinear interaction with other instabilities. The enhanced understanding of the physical mechanisms driving deleterious MHD activity given by these leading-edge capabilities has provided guidance to optimize operating scenarios for improved plasma performance.
dc.publisherIOP Publishing
dc.sourceNuclear Fusion
dc.subjectKeywords: Applied magnetic fields; Beta limit; Charge-exchange recombination spectroscopies; External coils; High performance plasma; High pressure; High resolution; Kinetic damping; Leading edge; Motional Stark effect diagnostic; Nonlinear interactions; Numerical
dc.titleMacroscopic stability of high β MAST plasmas
dc.typeJournal article
local.description.notesImported from ARIES
local.identifier.citationvolume51
dc.date.issued2011
local.identifier.absfor020204 - Plasma Physics; Fusion Plasmas; Electrical Discharges
local.identifier.ariespublicationu4695161xPUB137
local.type.statusPublished Version
local.contributor.affiliationChapman, I T, EURATOM/CCFE Fusion Association
local.contributor.affiliationCooper, W.A., Association EURATOM/Confederation Suisse
local.contributor.affiliationGraves, J.P., Association EURATOM/Confederation Suisse
local.contributor.affiliationGryaznevich, M P, EURATOM/CCFE Fusion Association
local.contributor.affiliationHastie, R.J., EURATOM/CCFE Fusion Association
local.contributor.affiliationHender, T.C., EURATOM/UKAEA Fusion Association
local.contributor.affiliationHowell, D F, EURATOM/CCFE Fusion Association
local.contributor.affiliationHua, M.-D., Imperial College of Science
local.contributor.affiliationHuysmans, G., CEA-Cadarache, Association Euratom-CEA
local.contributor.affiliationKeeling, D, EURATOM/CCFE Fusion Association
local.contributor.affiliationLiu, Y Q, EURATOM/CCFE Fusion Association
local.contributor.affiliationMeyer, H, EURATOM/CCFE Fusion Association
local.contributor.affiliationMichael, Clive, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationPinches, S D, EURATOM/CCFE Fusion Association
local.contributor.affiliationSaarelma, S., EURATOM/UKAEA Fusion Association
local.contributor.affiliationSabbagh, S.A., Columbia University
local.contributor.affiliationMAST Team, The, EURATOM/CCFE Fusion Assoc.
local.description.embargo2037-12-31
local.bibliographicCitation.issue7
local.bibliographicCitation.startpage073040
local.identifier.doi10.1088/0029-5515/51/7/073040
dc.date.updated2016-02-24T11:18:27Z
local.identifier.scopusID2-s2.0-79956110200
CollectionsANU Research Publications

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