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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Effects of neutrals on plasma rotation in DIII-D
TL;DR: In this article, the Hirshman and Sigmar neoclassical moment approach is used to determine the rotation velocities of the main plasma ions and of one impurity species, when charge exchange friction is included.
Journal ArticleDOI
Impact of plasma response on plasma displacements in DIII-D during application of external 3D perturbations
Andreas Wingen,Nathaniel Ferraro,Morgan Shafer,Ezekial A Unterberg,Todd Evans,D. L. Hillis,P. B. Snyder +6 more
TL;DR: In this paper, the effects of applied 3D resonant magnetic perturbations are modelled with and without self-consistent plasma response using a linear two-fluid model.
Journal ArticleDOI
On the formation and stability of long-lived impurity-ion snakes in Alcator C-Mod
L. Delgado-Aparicio,L. Delgado-Aparicio,L.E. Sugiyama,Robert Granetz,David Gates,John Rice,Matthew Reinke,W. Bergerson,W. Bergerson,Manfred Bitter,D. L. Brower,E.D. Fredrickson,C. Gao,Martin Greenwald,K. W. Hill,Amanda Hubbard,J. H. Irby,Jerry Hughes,Earl Marmar,N. A. Pablant,S. D. Scott,R. Wilson,S.M. Wolfe,S.J. Wukitch +23 more
TL;DR: In this paper, high-resolution spectroscopic imaging diagnostics permit studies of heavy-impurity ion snakes with unprecedented temporal and spatial resolution, making it possible to positively identify the SXR signals with specific ion charge states and to infer, for the first time, the perturbed impurity density, Zeff, and resistivity at the centre of these long-lived helical modes.
Journal ArticleDOI
Deep neural network Grad–Shafranov solver constrained with measured magnetic signals
Semin Joung,Jaewook Kim,Sehyun Kwak,J.G. Bak,Sanggon Lee,Hyunsun Han,Hyun-Seok Kim,Geunho Lee,Daeho Kwon,Young-chul Ghim +9 more
TL;DR: A neural network solving Grad-Shafranov equation constrained with measured magnetic signals to reconstruct magnetic equilibria in real time is developed and an imputation scheme is utilized to eliminate the required additional training sets with large number of possible combinations of the missing inputs.
Journal ArticleDOI
A new explanation of the sawtooth phenomena in tokamaks
TL;DR: In this paper, a new theory for the saw-tooth phenomena in auxiliary heated tokamaks is proposed, motivated by the recent understanding of magnetic flux pumping, which keeps the central safety factor, q 0, just above 1.0 with low central 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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