Journal ArticleDOI
Chapter 3: MHD stability, operational limits and disruptions
T. C. Hender,J.C. Wesley,J.M. Bialek,Anders Bondeson,Allen H. Boozer,R.J. Buttery,Am Garofalo,Timothy Goodman,Robert Granetz,Y. Gribov,O. Gruber,Mikhail Gryaznevich,G. Giruzzi,Sibylle Günter,Nobuhiko Hayashi,Per Helander,Chris Hegna,D. F. Howell,D.A. Humphreys,G. T. A. Huysmans,A.W. Hyatt,Akihiko Isayama,Stephen Jardin,Yasunori Kawano,A. Kellman,C.E. Kessel,H. R. Koslowski,R. J. La Haye,E. Lazzaro,Yueqiang Liu,V.E. Lukash,J. Manickam,S. Medvedev,V. Mertens,S. V. Mirnov,Y. Nakamura,G.A. Navratil,M. Okabayashi,Takahisa Ozeki,Roberto Paccagnella,G. Pautasso,F. Porcelli,V. D. Pustovitov,V. Riccardo,M. Sato,Olivier Sauter,M.J. Schaffer,Michiya Shimada,Piergiorgio Sonato,E. J. Strait,M. Sugihara,Manabu Takechi,A. D. Turnbull,E. Westerhof,D.G. Whyte,R. Yoshino,H. Zohm +56 more
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A review of recent advances in the area of MHD stability and disruptions, since the publication of the 1999 ITER Physics Basis document (1999 Nucl. Fusion 39 2137-2664), is reviewed in this paper.Abstract:
Progress in the area of MHD stability and disruptions, since the publication of the 1999 ITER Physics Basis document (1999 Nucl. Fusion 39 2137-2664), is reviewed. Recent theoretical and experimental research has made important advances in both understanding and control of MHD stability in tokamak plasmas. Sawteeth are anticipated in the ITER baseline ELMy H-mode scenario, but the tools exist to avoid or control them through localized current drive or fast ion generation. Active control of other MHD instabilities will most likely be also required in ITER. Extrapolation from existing experiments indicates that stabilization of neoclassical tearing modes by highly localized feedback-controlled current drive should be possible in ITER. Resistive wall modes are a key issue for advanced scenarios, but again, existing experiments indicate that these modes can be stabilized by a combination of plasma rotation and direct feedback control with non-axisymmetric coils. Reduction of error fields is a requirement for avoiding non-rotating magnetic island formation and for maintaining plasma rotation to help stabilize resistive wall modes. Recent experiments have shown the feasibility of reducing error fields to an acceptable level by means of non-axisymmetric coils, possibly controlled by feedback. The MHD stability limits associated with advanced scenarios are becoming well understood theoretically, and can be extended by tailoring of the pressure and current density profiles as well as by other techniques mentioned here. There have been significant advances also in the control of disruptions, most notably by injection of massive quantities of gas, leading to reduced halo current fractions and a larger fraction of the total thermal and magnetic energy dissipated by radiation. These advances in disruption control are supported by the development of means to predict impending disruption, most notably using neural networks. In addition to these advances in means to control or ameliorate the consequences of MHD instabilities, there has been significant progress in improving physics understanding and modelling. This progress has been in areas including the mechanisms governing NTM growth and seeding, in understanding the damping controlling RWM stability and in modelling RWM feedback schemes. For disruptions there has been continued progress on the instability mechanisms that underlie various classes of disruption, on the detailed modelling of halo currents and forces and in refining predictions of quench rates and disruption power loads. Overall the studies reviewed in this chapter demonstrate that MHD instabilities can be controlled, avoided or ameliorated to the extent that they should not compromise ITER operation, though they will necessarily impose a range of constraints.read more
Citations
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Journal ArticleDOI
Nonlinear simulation of ELM dynamics in the presence of resonant magnetic perturbations
Journal ArticleDOI
Effect of magnetic fluctuations on the confinement and dynamics of runaway electrons in the HT-7 tokamak
TL;DR: In this article, a radial runaway diffusion coefficient of Dr≈10m2s-1 was derived for the loss processes in the HT-7 tokamak, and diffusion coefficient near the resonant magnetic surfaces and shielding factor ϒ=0.8 were deduced.
Journal ArticleDOI
Suppression of runaway electron generation by massive helium injection after induced disruptions on TEXTOR
TL;DR: In this paper, a second disruption mitigation valve has been used to inject varying amounts of helium after a short time delay, and no generation of runaway electrons has been observed when more than a critical amount of helium has been injected no later than 5 milliseconds after the triggering of the first valve.
Journal ArticleDOI
The study of heat flux for disruption on experimental advanced superconducting tokamak
Zhendong Yang,Zhendong Yang,Jianan Fang,Xianzu Gong,Kaifu Gan,Jia-Rong Luo,Hailin Zhao,Zhi-Xue Cui,Bin Zhang,Meiwen Chen +9 more
TL;DR: In this paper, the authors focused on the characteristics of heat flux distribution onto the first wall under different disruptions, including the minor disruption and the vertical displacement events (VDE) disruption.
Journal ArticleDOI
Halo current diagnostic system of experimental advanced superconducting tokamak
TL;DR: Initial measurements from disruptions show that the halo current diagnostics are working well, and the design, calibration, and installation of disruption haloCurrent sensors for the Experimental Advanced Superconducting Tokamak are described.
References
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Journal ArticleDOI
Chapter 1: Overview and summary
TL;DR: The ITER Physics Basis as mentioned in this paper presents and evaluates the physics rules and methodologies for plasma performance projections, which provide the basis for the design of a tokamak burning plasma device whose goal is to demonstrate the scientific and technological feasibility of fusion energy for peaceful purposes.
Journal ArticleDOI
Chapter 4: Power and particle control
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Journal ArticleDOI
Chapter 2: Plasma confinement and transport
E. J. Doyle,Wayne A Houlberg,Yutaka Kamada,V. S. Mukhovatov,T.H. Osborne,A. R. Polevoi,G. Bateman,J. W. Connor,J. G. Cordey,T. Fujita,Xavier Garbet,T. S. Hahm,L. D. Horton,A. E. Hubbard,F. Imbeaux,Frank Jenko,J. E. Kinsey,Yasuaki Kishimoto,J.X. Li,T. C. Luce,Y. R. Martin,M. Ossipenko,V.V. Parail,A. G. Peeters,T. L. Rhodes,J. E. Rice,C. M. Roach,V. A. Rozhansky,F. Ryter,G. Saibene,R. Sartori,A. C. C. Sips,J. A. Snipes,M. Sugihara,E. J. Synakowski,H. Takenaga,Tomonori Takizuka,K. Thomsen,M. R. Wade,H. R. Wilson,Itpa Confinement Database,Itpa Pedestal +41 more
TL;DR: The understanding and predictive capability of transport physics and plasma confinement is reviewed from the perspective of achieving reactor-scale burning plasmas in the ITER tokamak, for both core and edge plasma regions.
Journal ArticleDOI
Equilibrium analysis of current profiles in tokamaks
TL;DR: In this paper, an efficient method is given for self-consistent reconstruction of the tokamak current profiles and their associated magnetic topology using the magnetohydrodynamic (MHD) equilibrium constraint from external magnetic measurements, kinetic profile measurements, internal poloidal magnetic field measurements, and topological information from soft X-ray (SXR) measurements.
Journal ArticleDOI
Helical temperature perturbations associated with tearing modes in tokamak plasmas
TL;DR: In this article, an investigation into the electron temperature perturbations associated with tearing modes in tokamak plasmas was made, and it was found that there is a critical magnetic island width below which the conventional picture where the temperature is flattened inside the separatrix is invalid.
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