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
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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
Chapter 1: Overview and summary
M. Shimada,David Campbell,V. Mukhovatov,M. Fujiwara,N. Kirneva,K. Lackner,M. Nagami,V. D. Pustovitov,N. Uckan,J. Wesley,N. Asakura,A.E. Costley,A. J. H. Donne,E. J. Doyle,Ambrogio Fasoli,C. Gormezano,Y. Gribov,O. Gruber,T. C. Hender,W. Houlberg,S. Ide,Y. Kamada,A. Leonard,Bruce Lipschultz,A. Loarte,Kenro Miyamoto,T. H. Osborne,A. Polevoi,A. C. C. Sips +28 more
TL;DR: The progress in the ITER Physics Basis (PIPB) document as discussed by the authors is an update of the IPB, which was published in 1999 [1], and provides methodologies for projecting the performance of burning plasmas, developed largely through coordinated experimental, modelling and theoretical activities carried out on today's large tokamaks (ITER Physics R&D).
Journal ArticleDOI
Chapter 6: Steady state operation
C. Gormezano,A. C. C. Sips,T. C. Luce,S. Ide,A. Becoulet,X. Litaudon,A. Isayama,J. Hobirk,M. R. Wade,T. Oikawa,R. Prater,A. Zvonkov,B. Lloyd,T. Suzuki,E. Barbato,P. T. Bonoli,C. K. Phillips,V. Vdovin,E. Joffrin,T. A. Casper,J. R. Ferron,D. Mazon,D. Moreau,R. Bundy,C. E. Kessel,A. Fukuyama,N. Hayashi,F. Imbeaux,M. Murakami,A. R. Polevoi,H. E. St John +30 more
TL;DR: The actuators for heating and current drive that are necessary to produce and control the advanced tokamak discharges are discussed, including modelling and predictions for ITER, and specific control issues for steady state operation are discussed.
Model for the sawtooth period and amplitude
TL;DR: In this paper, a model for sawtooth oscillations in tokamak experiments is outlined, and a threshold criterion for the onset of internal kink modes and a prescription for the relaxed profiles immediately after the saw-tooth crash have been implemented in a transport code that evolves the relevant plasma parameters.
Journal ArticleDOI
Magnetic control of tokamak plasmas through deep reinforcement learning
Jonas Degrave,Federico Felici,Jonas Buchli,Michael Neunert,Brendan D. Tracey,Francesco Carpanese,Timo Ewalds,Roland Hafner,Abbas Abdolmaleki,Diego de Las Casas,Craig Donner,Leslie Fritz,C. Galperti,Andrea Huber,James Keeling,Maria Tsimpoukell,Jackie Kay,Antoine Merle,Jean-Marc Moret,Seb Noury,F. Pesamosca,D. Pfau,Olivier Sauter,C. Sommariva,Stefano Coda,B. P. Duval,Ambrogio Fasoli,Pushmeet Kohli,Koray Kavukcuoglu,Demis Hassabis,Martin Riedmiller +30 more
TL;DR: In this paper , a novel architecture for tokamak magnetic controller design that autonomously learns to command the full set of control coils is presented. But this approach has unprecedented flexibility and generality in problem specification and yields a notable reduction in design effort to produce new plasma configurations.
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TL;DR: Lower hybrid current drive (LHCD) with modest powers has been used for the first time to completely stabilize performance limiting neoclassical tearing modes in many COMPASS-D tokamak discharges.
Journal ArticleDOI
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TL;DR: This Letter provides the first experimental evidence for the effectiveness of this method in the different physics regime associated with fast-ion-induced long sawteeth on the JET tokamak.
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