Journal ArticleDOI
Reconstruction of current profile parameters and plasma shapes in tokamaks
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TLDR
In this paper, an efficient method is given to reconstruct the current profile parameters, the plasma shape, and a current profile consistent with the magnetohydrodynamic equilibrium constraint from external magnetic measurements, based on a Picard iteration approach.Abstract:
An efficient method is given to reconstruct the current profile parameters, the plasma shape, and a current profile consistent with the magnetohydrodynamic equilibrium constraint from external magnetic measurements, based on a Picard iteration approach which approximately conserves the measurements. Computational efforts are reduced by parametrizing the current profile linearly in terms of a number of physical parameters. Results of detailed comparative calculations and a sensitivity study are described. Illustrative calculations to reconstruct the current profiles and plasma shapes in ohmically and auxiliarily heated Doublet III plasmas are given which show many interesting features of the current profiles.read more
Citations
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Journal ArticleDOI
Machine learning for disruption warnings on Alcator C-Mod, DIII-D, and EAST
Kevin Montes,Cristina Rea,Robert Granetz,Roy Tinguely,N.W. Eidietis,Orso Meneghini,Dalong Chen,Biao Shen,Bingjia Xiao,Keith Erickson,M. D. Boyer +10 more
TL;DR: A shallow machine learning method known as a random forest, trained on large databases containing only plasma parameters that are available in real-time on Alcator C-Mod, DIII-D, and EAST, finds that the prediction algorithms differ substantially in performance among the three machines on a time slice-by-time slice basis, but have similar disruption detection rates after appropriate optimisation.
Journal ArticleDOI
The resistive wall mode and feedback control physics design in NSTX
Steven Sabbagh,J.M. Bialek,R. E. Bell,Alan H. Glasser,B.P. LeBlanc,Jonathan Menard,F. Paoletti,M.G. Bell,Richard Fitzpatrick,E.D. Fredrickson,Am Garofalo,David Gates,Stanley Kaye,L.L. Lao,Rajesh Maingi,D. Mueller,G.A. Navratil,Dan Stutman,W. Zhu +18 more
TL;DR: In this article, the authors investigated the physics of global mode stabilization in a low aspect ratio device, and the most effective configuration was computed to provide stabilization at βN up to 94% of the ideal with-wall limit.
Journal ArticleDOI
Measurements and implications of Zeff profiles on the DIII‐D tokamak
TL;DR: In this paper, Zeff profiles have been obtained across the entire minor radius of the DIII-D [Fusion Technol. 8, 441] tokamak from measurements of visible bremsstrahlung continuum radiation.
Journal ArticleDOI
Fast reciprocating probe system on the EAST superconducting tokamak.
Wei Zhang,J. F. Chang,B. N. Wan,Guosheng Xu,Chijin Xiao,Bo Li,C. S. Xu,Ning Yan,L. Wang,S. C. Liu,Min Jiang,Peiliang Liu +11 more
TL;DR: A new fast reciprocating probe system (FRPS) has been built and installed on the outer midplane of the EAST tokamak to investigate the profiles of the boundary plasma parameters such as electron density and temperature.
Journal ArticleDOI
Characterization of 3D filament dynamics in a MAST SOL flux tube geometry
TL;DR: In this article, non-linear simulations of filament propagation in a realistic MAST SOL flux tube geometry using the BOUT++ fluid modelling framework show an isolation of the dynamics of the filament in the divertor region from the midplane region due to three features of magnetic geometry; the variation of magnetic curvature along the field line, the expansion of the flux tube and strong magnetic shear.
References
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Journal ArticleDOI
Separation of β̄p and ℓi in tokamaks of non-circular cross-section
TL;DR: In this paper, integral relations for the average poloidal beta p and the plasma internal inductance li are derived from the magnetohydrodynamic (MHD) equilibrium equation for an axisymmetric torus.
Journal ArticleDOI
Computation of ideal MHD equilibria
TL;DR: In this paper, a review of two-and three-dimensional ideal MHD equilibrium codes, with particular emphasis on axisymmetric toroidal calculations, is presented. But this paper is restricted to the case of Tokyoamak geometry.
Journal ArticleDOI
An efficient technique for magnetic analysis of non-circular, high-beta tokamak equilibria
D.W. Swain,G.H. Neilson +1 more
TL;DR: In this paper, a method for determining plasma shape and global properties of high-beta non-circular tokamak equilibria (βp, β, q and li) from magnetic sensor data is described.
Journal ArticleDOI
Magnetic analysis of non-circular cross-section tokamaks
J.L. Luxon,B.B. Brown +1 more
TL;DR: In this paper, the MHD equilibrium configuration for circular and non-circular plasmas from measurements of the magnetic field and flux made outside the discharge was determined using least squares minimization techniques.
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