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Abstract
The concept and structure of the Simulation of Spectra (SOS) code is described starting with an introduction to the physics background of the project and the development of a simulation tool enabling the modeling of charge-exchange recombination spectroscopy (CXRS) and associated passive background spectra observed in hot fusion plasmas. The generic structure of the code implies its general applicability to any fusion device, the development is indeed based on over two decades of spectroscopic observations and validation of derived plasma data. Four main types of active spectra are addressed in SOS. The first type represents thermal low-Z impurity ions and the associated spectral background. The second type of spectra represent slowing-down high energy ions created from either thermo-nuclear fusion reactions or ions from injected high energy neutral beams. Two other modules are dedicated to CXRS spectra representing bulk plasma ions (H+, D+, or T+) and beam emission spectroscopy (BES) or Motional Stark Effect (MSE) spectrum appearing in the same spectral range. The main part of the paper describes the physics background for the underlying emission processes: active and passive CXRS emission, continuum radiation, edge line emission, halo and plume effect, or finally the charge exchange (CX) cross-section effects on line shapes. The description is summarized by modeling the fast ions emissions, e.g., either of the α particles of the fusion reaction or of the beam ions itself.
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Nakamura K, Alam M, Jiang Y, Mitarai O, Kurihara K, Kawamata Y, Sueoka M, Takechi M, Hasegawa M, Tokunaga K, Araki K, Zushi H, Hanada K, Fujisawa A, Idei H, Nagashima Y, Kawasaki S, Nakashima H, Higashijima A, Nagata T, Fukuyama A. Plasma equilibrium based on RF-driven current profile without assuming nested magnetic surfaces on QUEST. FUSION ENGINEERING AND DESIGN 2017. [DOI: 10.1016/j.fusengdes.2017.05.070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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3
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Kamada Y, Fujita T, Ishida S, Kikuchi M, Ide S, Takizuka T, Shirai H, Koide Y, Fukuda T, Hosogane N, Tsuchiya K, Hatae T, Takenaga H, Sato M, Nakamura H, Naito O, Asakura N, Kubo H, Higashijima S, Miura Y, Yoshino R, Shimizu K, Ozeki T, Hirayama T, Mori M, Sakamoto Y, Kawano Y, Isayama A, Ushigusa K, Ikeda Y, Kimura H, Fujii T, Imai T, Nagami M, Takeji S, Oikawa T, Suzuki T, Nakano T, Oyama N, Sakurai S, Konoshima S, Sugie T, Tobita K, Kondoh T, Tamai H, Neyatani Y, Sakasai A, Kusama Y, Itami K, Shimada M, Ninomiya H, Urano H. Fusion Plasma Performance and Confinement Studies on JT-60 and JT-60U. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst02-a227] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Y. Kamada
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - T. Fujita
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - S. Ishida
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - M. Kikuchi
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - S. Ide
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - T. Takizuka
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - H. Shirai
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - Y. Koide
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - T. Fukuda
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - N. Hosogane
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - K. Tsuchiya
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - T. Hatae
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - H. Takenaga
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - M. Sato
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - H. Nakamura
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - O. Naito
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - N. Asakura
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - H. Kubo
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - S. Higashijima
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - Y. Miura
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - R. Yoshino
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - K. Shimizu
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - T. Ozeki
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - T. Hirayama
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - M. Mori
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - Y. Sakamoto
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - Y. Kawano
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - A. Isayama
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - K. Ushigusa
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - Y. Ikeda
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - H. Kimura
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - T. Fujii
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - T. Imai
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - M. Nagami
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - S. Takeji
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - T. Oikawa
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - T. Suzuki
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - T. Nakano
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - N. Oyama
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - S. Sakurai
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - S. Konoshima
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - T. Sugie
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - K. Tobita
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - T. Kondoh
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - H. Tamai
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - Y. Neyatani
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - A. Sakasai
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - Y. Kusama
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - K. Itami
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - M. Shimada
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
| | - H. Ninomiya
- Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan
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Tobita K, Kusama Y, Shinohara K, Nishitani T, Kimura H, Kramer GJ, Nemoto M, Kondoh T, Oikawa T, Morioka A, Hamamatsu K, Wang S, Takeji S, Takechi M, Ishikawa M, Tani K, Saigusa M, Ozeki T. Energetic Particle Experiments in JT-60U and Their Implications for a Fusion Reactor. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst02-a231] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- K. Tobita
- Japan Atomic Energy Research Institute, Naka-machi, Naka-gun, Ibaraki 311-0193, Japan
| | - Y. Kusama
- Japan Atomic Energy Research Institute, Naka-machi, Naka-gun, Ibaraki 311-0193, Japan
| | - K. Shinohara
- Japan Atomic Energy Research Institute, Naka-machi, Naka-gun, Ibaraki 311-0193, Japan
| | - T. Nishitani
- Japan Atomic Energy Research Institute, Naka-machi, Naka-gun, Ibaraki 311-0193, Japan
| | - H. Kimura
- Japan Atomic Energy Research Institute, Naka-machi, Naka-gun, Ibaraki 311-0193, Japan
| | - G. J. Kramer
- Japan Atomic Energy Research Institute, Naka-machi, Naka-gun, Ibaraki 311-0193, Japan
| | - M. Nemoto
- Japan Atomic Energy Research Institute, Naka-machi, Naka-gun, Ibaraki 311-0193, Japan
| | - T. Kondoh
- Japan Atomic Energy Research Institute, Naka-machi, Naka-gun, Ibaraki 311-0193, Japan
| | - T. Oikawa
- Japan Atomic Energy Research Institute, Naka-machi, Naka-gun, Ibaraki 311-0193, Japan
| | - A. Morioka
- Japan Atomic Energy Research Institute, Naka-machi, Naka-gun, Ibaraki 311-0193, Japan
| | - K. Hamamatsu
- Japan Atomic Energy Research Institute, Naka-machi, Naka-gun, Ibaraki 311-0193, Japan
| | - S. Wang
- Japan Atomic Energy Research Institute, Naka-machi, Naka-gun, Ibaraki 311-0193, Japan
| | - S. Takeji
- Japan Atomic Energy Research Institute, Naka-machi, Naka-gun, Ibaraki 311-0193, Japan
| | - M. Takechi
- Japan Atomic Energy Research Institute, Naka-machi, Naka-gun, Ibaraki 311-0193, Japan
| | - M. Ishikawa
- Japan Atomic Energy Research Institute, Naka-machi, Naka-gun, Ibaraki 311-0193, Japan
| | - K. Tani
- Japan Atomic Energy Research Institute, Naka-machi, Naka-gun, Ibaraki 311-0193, Japan
| | - M. Saigusa
- Japan Atomic Energy Research Institute, Naka-machi, Naka-gun, Ibaraki 311-0193, Japan
| | - T. Ozeki
- Japan Atomic Energy Research Institute, Naka-machi, Naka-gun, Ibaraki 311-0193, Japan
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5
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Kikuchi M, Campbell DJ. Physics of Plasma Control Toward Steady-State Operation of ITER. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst11-a11689] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- M. Kikuchi
- Japan Atomic Energy Agency, Mukoyama 801-1, Naka, Ibaraki 311-0193, Japan
| | - D. J. Campbell
- ITER Organization, Route de Vinon sur Verdon, F-13115 St Paul lez Durance, France
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Noterdaeme JM, Eriksson LG, Mantsinen M, Mayoral ML, Eester DV, Mailloux J, Gormezano C, Jones TTC. Chapter 9: Physics Studies with the Additional Heating Systems in JET. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst08-a1749] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- J.-M. Noterdaeme
- Max-Planck-Institut für Plasmaphysik, Euratom-Association IPP, D-85740 Garching, Germany
- University of Gent, Electrical Energy, Systems, and Automation Department, Gent, Belgium
| | - L.-G. Eriksson
- Association Euratom-CEA, CEA/DSM/DRFC Centre de Cadarache, 13108 St. Paul lez Durance, France
| | - M. Mantsinen
- Helsinki University of Technology, EURATOM-Association TEKES, Helsinki, Finland
| | - M.-L. Mayoral
- Euratom/UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - D. Van Eester
- Laboratory for Plasmas Physics, Association “EURATOM – Belgian State,” ERM-KMS, Trilateral Euregio Cluster Brussels, Belgium
| | - J. Mailloux
- Euratom/UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | | | - T. T. C. Jones
- Euratom/UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
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7
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Gormezano C, Challis CD, Joffrin E, Litaudon X, Sips ACC. Chapter 4: Advanced Tokamak Scenario Development at JET. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst08-a1744] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
| | - C. D. Challis
- Euratom/UKAEA Fusion Association Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - E. Joffrin
- Association Euratom-CEA CEA/DSM/DRFC Centre de Cadarache, 13108 St Paul lez Durance, France
| | - X. Litaudon
- Association Euratom-CEA CEA/DSM/DRFC Centre de Cadarache, 13108 St Paul lez Durance, France
| | - A. C. C. Sips
- Max-Planck-Institut für Plasmaphysik, Euratom-Association IPP, D-85740 Garching, Germany
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8
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Analysis of plasma equilibrium based on orbit-driven current density profile in steady-state plasma on QUEST. FUSION ENGINEERING AND DESIGN 2016. [DOI: 10.1016/j.fusengdes.2015.11.035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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9
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Brookhart MI, Stemo A, Zuberbier A, Zweibel E, Forest CB. Instability, turbulence, and 3D magnetic reconnection in a line-tied, zero net current screw pinch. PHYSICAL REVIEW LETTERS 2015; 114:145001. [PMID: 25910129 DOI: 10.1103/physrevlett.114.145001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Indexed: 06/04/2023]
Abstract
This Letter reports the first experimental investigation into a line-tied plasma with a reversed current profile. Discrete current sources create a cylindrical plasma equilibrium with an axial field and zero net current. Detailed magnetic measurements show that an internal m=1 mode with no external character grows exponentially. The nonlinear evolution of the mode drives 3D reconnection events that reorganize the plasma equilibrium. The plasma is turbulent and exhibits reconnection events on a range of scales. These data are consistent with recent simulations of coronal loops and the nanoflare coronal heating mechanism.
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Affiliation(s)
| | - Aaron Stemo
- University of Wisconsin-Madison, Madison, Wisconsin, USA
| | | | - Ellen Zweibel
- University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Cary B Forest
- University of Wisconsin-Madison, Madison, Wisconsin, USA
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10
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Cook JWS, Chapman SC, Dendy RO. Electron current drive by fusion-product-excited lower hybrid drift instability. PHYSICAL REVIEW LETTERS 2010; 105:255003. [PMID: 21231597 DOI: 10.1103/physrevlett.105.255003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Indexed: 05/30/2023]
Abstract
We present first principles simulations of the direct collisionless coupling of the free energy of fusion-born ions into electron current in a magnetically confined fusion plasma. These simulations demonstrate, for the first time, a key building block of some "alpha channeling" scenarios for tokamak experiments. Spontaneously excited obliquely propagating waves in the lower hybrid frequency range undergo Landau damping on resonant electrons, drawing out an asymmetric tail in the electron parallel velocity distribution, which carries a current.
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Affiliation(s)
- J W S Cook
- Centre for Fusion Space and Astrophysics, Department of Physics, Warwick University, Coventry CV4 7AL, United Kingdom
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11
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A Review of Fusion and Tokamak Research Towards Steady-State Operation: A JAEA Contribution. ENERGIES 2010. [DOI: 10.3390/en3111741] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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12
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Brix M, Hawkes NC, Boboc A, Drozdov V, Sharapov SE. Accuracy of EFIT equilibrium reconstruction with internal diagnostic information at JET. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2008; 79:10F325. [PMID: 19068529 DOI: 10.1063/1.2964180] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In tokamak experiments, equilibrium reconstruction codes are used to calculate the location of the last closed flux surface, to map diagnostic information, and to derive important properties like current density and safety factor. At JET, the equilibrium code EFIT is automatically executed after each discharge. For speed and robustness, intershot EFIT is based on magnetic probe measurements only. As a consequence, the intershot profiles of the safety factor can be wrong for a variety of plasma scenarios. Internal diagnostic information, the pitch angle as measured with the motional stark effect, Faraday rotation angles, as well as pressure profile information can increase the accuracy of the EFIT equilibrium. In this paper, the accuracy of the internal diagnostics at JET and their impact on the EFIT results are discussed in detail. The influence of control parameters like the form of the test functions for ff' and p' on the equilibrium is investigated. The q(min) from this analysis agrees with information from magnetohydrodynamics analysis (e.g., Alfvén cascades and sawtooth analysis) to within 10%-15%.
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Affiliation(s)
- M Brix
- JET-EFDA, EURATOM/UKAEA Fusion Association, Culham Science Centre, Abingdon OX14 3DB, United Kingdom.
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Rodrigues P, Bizarro JPS. Tokamak equilibria with toroidal-current reversal in the plasma core consistent with experimental data. PHYSICAL REVIEW LETTERS 2007; 99:125001. [PMID: 17930511 DOI: 10.1103/physrevlett.99.125001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2007] [Indexed: 05/25/2023]
Abstract
For the first time, tokamak equilibria with negative toroidal current flowing in the plasma core are computed consistently with available measurements from typical current-hole discharges. The equilibrium reconstruction, which leads to non-nested configurations where a system of axisymmetric magnetic islands unfolds, yields an overall good agreement between the computed and experimental plasma-pressure profiles, together with an excellent fit to motional-Stark-effect data. Therefore, considering the accuracy limits of present-day experimental results, care must be exercised when ruling out the existence of tokamak equilibria with central toroidal-current reversal, particularly if relying on reconstruction tools that cannot cope with non-nested configurations.
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Affiliation(s)
- Paulo Rodrigues
- Centro de Fusão Nuclear, Associação Euratom-IST, Instituto Superior Técnico, 1049-001 Lisboa, Portugal.
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14
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Crombé K, Andrew Y, Brix M, Giroud C, Hacquin S, Hawkes NC, Murari A, Nave MFF, Ongena J, Parail V, Van Oost G, Voitsekhovitch I, Zastrow KD. Poloidal rotation dynamics, radial electric field, and neoclassical theory in the jet internal-transport-barrier region. PHYSICAL REVIEW LETTERS 2005; 95:155003. [PMID: 16241733 DOI: 10.1103/physrevlett.95.155003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2005] [Indexed: 05/05/2023]
Abstract
Results from the first measurements of a core plasma poloidal rotation velocity (upsilontheta) across internal transport barriers (ITB) on JET are presented. The spatial and temporal evolution of the ITB can be followed along with the upsilontheta radial profiles, providing a very clear link between the location of the steepest region of the ion temperature gradient and localized spin-up of upsilontheta. The upsilontheta measurements are an order of magnitude higher than the neoclassical predictions for thermal particles in the ITB region, contrary to the close agreement found between the determined and predicted particle and heat transport coefficients [K.-D. Zastrow, Plasma Phys. Controlled Fusion 46, B255 (2004)]. These results have significant implications for the understanding of transport barrier dynamics due to their large impact on the measured radial electric field profile.
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Affiliation(s)
- K Crombé
- Department of Applied Physics, Ghent University, Belgium
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15
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Fujita T, Suzuki T, Oikawa T, Isayama A, Hatae T, Naito O, Sakamoto Y, Hayashi N, Hamamatsu K, Ide S, Takenaga H. Current clamp at zero level in JT-60U current hole plasmas. PHYSICAL REVIEW LETTERS 2005; 95:075001. [PMID: 16196788 DOI: 10.1103/physrevlett.95.075001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2004] [Indexed: 05/04/2023]
Abstract
It is found that no current is driven in a central region of a tokamak plasma once the central current density becomes nearly zero ("current hole"), in spite of high electric conductivity, at the current drive by a toroidal electric field and a radio-frequency wave in experiments on the JT-60U tokamak. This is a new, stiff, self-organized structure of a magnetic field in an axisymmetric toroidal plasma.
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Affiliation(s)
- T Fujita
- Japan Atomic Energy Research Institute, Naka Fusion Research Establishment, Ibaraki-ken
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16
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Rodrigues P, Bizarro JPS. Grad-Shafranov equilibria with negative core toroidal current in Tokamak plasmas. PHYSICAL REVIEW LETTERS 2005; 95:015001. [PMID: 16090623 DOI: 10.1103/physrevlett.95.015001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2005] [Indexed: 05/03/2023]
Abstract
Numerical Grad-Shafranov (GS) equilibria with negative current density in the plasma core are computed which do not impose any particularly chosen models for the pressure and current-density profiles. This flexibility allows the profiles to be tailored so that an island unfolds in the low-field side, even for elongated plasmas, thus sustaining the negative-current core against outward forces. Among other topological results, reversed GS equilibria are also shown to be necessarily non-nested, except for the cylindrical and other very special degenerate, hence structurally unstable cases.
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Affiliation(s)
- Paulo Rodrigues
- Centro de Fusão Nuclear, Associação Euratom--IST, Instituto Superior Técnico, 1049-001 Lisboa, Portugal.
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17
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Wang S. Theory of tokamak equilibria with central current density reversal. PHYSICAL REVIEW LETTERS 2004; 93:155007. [PMID: 15524896 DOI: 10.1103/physrevlett.93.155007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2004] [Indexed: 05/24/2023]
Abstract
It is found that, with a model current profile, the Grad-Shafranov equation can be reduced to the Helmholtz equation, which can describe a variety of equilibrium configurations. With the eigenvalue problem solved in the toroidal coordinate system, an analytical solution to the Grad-Shafranov equation is found. It is demonstrated that current reversal equilibrium configurations exist with finite radial gradient of plasma pressure and continuous current density, and that current density reversal is accompanied by pressure gradient reversal.
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Affiliation(s)
- Shaojie Wang
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui, 230031, China.
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18
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Kiptily VG, Baranov YF, Barnsley R, Bertalot L, Hawkes NC, Murari A, Popovichev S, Sharapov SE, Stork D, Yavorskij V. First gamma-ray measurements of fusion alpha particles in JET trace tritium experiments. PHYSICAL REVIEW LETTERS 2004; 93:115001. [PMID: 15447347 DOI: 10.1103/physrevlett.93.115001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2004] [Indexed: 05/24/2023]
Abstract
Gamma-ray spectra from nuclear reactions between fusion-born alpha (alpha) particles and Be impurities were measured for the first time in deuterium-tritium plasmas in the Joint European Torus. The time dependence of the measured spectra allowed the determination of the density evolution of fast alpha particles. Correlation between the decay time of the gamma-ray emission and the plasma parameters in different plasma scenarios was established. Results are consistent with classical slowing down of the alpha particles in discharges with high plasma currents and monotonic q-profiles. In low plasma current discharges and in the discharges with large on-axis current holes (extreme reversal central magnetic shear), the gamma-ray emission decay times are shorter than the classical slowing down times, indicating an alpha-particle confinement degradation in such discharges in line with theoretical predictions.
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Affiliation(s)
- V G Kiptily
- Euratom/UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxon, OX14 3DB, United Kingdom
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19
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Tamai H, Ishida S, Kurita GI, Shirai H, Tsuchiya K, Sakurai S, Matsukawa M, Sakasai A. Steady-State Operation Scenarios with a Central Current Hole for JT-60SC. FUSION SCIENCE AND TECHNOLOGY 2004. [DOI: 10.13182/fst04-a527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Hiroshi Tamai
- Japan Atomic Energy Research Institute, Naka Fusion Research Establishment, Naka, Ibaraki 311-0193, Japan
| | - Shinichi Ishida
- Japan Atomic Energy Research Institute, Naka Fusion Research Establishment, Naka, Ibaraki 311-0193, Japan
| | - Gen-Ichi Kurita
- Japan Atomic Energy Research Institute, Naka Fusion Research Establishment, Naka, Ibaraki 311-0193, Japan
| | - Hiroshi Shirai
- Japan Atomic Energy Research Institute, Naka Fusion Research Establishment, Naka, Ibaraki 311-0193, Japan
| | - Katsuhiko Tsuchiya
- Japan Atomic Energy Research Institute, Naka Fusion Research Establishment, Naka, Ibaraki 311-0193, Japan
| | - Shinji Sakurai
- Japan Atomic Energy Research Institute, Naka Fusion Research Establishment, Naka, Ibaraki 311-0193, Japan
| | - Makoto Matsukawa
- Japan Atomic Energy Research Institute, Naka Fusion Research Establishment, Naka, Ibaraki 311-0193, Japan
| | - Akira Sakasai
- Japan Atomic Energy Research Institute, Naka Fusion Research Establishment, Naka, Ibaraki 311-0193, Japan
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20
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Cesario R, Cardinali A, Castaldo C, Paoletti F, Mazon D. Modeling of a lower-hybrid current drive by including spectral broadening induced by parametric instability in tokamak plasmas. PHYSICAL REVIEW LETTERS 2004; 92:175002. [PMID: 15169159 DOI: 10.1103/physrevlett.92.175002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2003] [Indexed: 05/24/2023]
Abstract
By incorporating parametric instabilities of lower hybrid (LH) waves into a ray-tracing Fokker-Planck code, accurate simulations of the LH deposition profiles are provided, which are useful for interpreting the long-lasting internal transport barriers (ITBs) sustained by lower hybrid current drive (LHCD) on JET (Joint European Torus). Utilizing the new model, the simulation of the q-profile evolution results in agreement with that provided by the motional Stark effect reconstructed equilibria. Low magnetic shear (s approximately equal to 0) is produced by LHCD in a layer close to the ITB radial foot.
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Affiliation(s)
- R Cesario
- Associazione EURATOM-ENEA sulla Fusione, Centro Ricerche Frascati c.p. 65, 00044 Frascati, Italy.
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21
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Shiraiwa S, Ide S, Itoh S, Mitarai O, Naito O, Ozeki T, Sakamoto Y, Suzuki T, Takase Y, Tanaka S, Taniguchi T, Aramasu M, Fujita T, Fukuda T, Gao X, Gryaznevich M, Hanada K, Jotaki E, Kamada Y, Maekawa T, Miura Y, Nakamura K, Nishi T, Tanaka H, Ushigusa K. Formation of advanced tokamak plasmas without the use of an ohmic-heating solenoid. PHYSICAL REVIEW LETTERS 2004; 92:035001. [PMID: 14753880 DOI: 10.1103/physrevlett.92.035001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2003] [Indexed: 05/24/2023]
Abstract
A new operational scenario of advanced tokamak formation was demonstrated in the JT-60U tokamak. This was accomplished by electron cyclotron and lower hybrid waves, neutral beam injection, and the loop voltage supplied by the vertical field and shaping coils. The Ohmic heating (OH) solenoid was not used but a small inboard coil (part of the shaping coil), providing less than 20% of total poloidal flux, was used. The plasma thus obtained had both internal and edge transport barriers, with an energy confinement time of 1.6 times H-mode scaling, a poloidal beta of 3.6, and a normalized beta of 1.6, and a large bootstrap current fraction (>90%). This result opens up a possibility to reduce, and eventually eliminate, the OH solenoid from a tokamak reactor, which will greatly improve its economic competitiveness.
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Affiliation(s)
- S Shiraiwa
- Graduate School of Frontier Sciences, University of Tokyo, Tokyo 113-0033, Japan.
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22
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Martynov AA, Medvedev SY, Villard L. Tokamak equilibria with reversed current density. PHYSICAL REVIEW LETTERS 2003; 91:085004. [PMID: 14525248 DOI: 10.1103/physrevlett.91.085004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2003] [Indexed: 05/24/2023]
Abstract
Observations of nearly zero toroidal current in the central region of tokamaks (the "current hole") raises the question of the existence of toroidal equilibria with very low or reversed current in the core. The solutions of the Grad-Shafranov equilibrium equation with hollow toroidal current density profile including negative current density in the plasma center are investigated. Solutions of the corresponding eigenvalue problem provide simple examples of such equilibrium configurations. More realistic equilibria with toroidal current density reversal are computed using a new equilibrium problem formulation and computational algorithm which do not assume nested magnetic surfaces.
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Affiliation(s)
- A A Martynov
- Keldysh Institute of Applied Mathematics, Russian Academy of Sciences, Moscow, Russia
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23
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Crisanti F, Litaudon X, Mailloux J, Mazon D, Barbato E, Baranov Y, Bécoulet A, Bécoulet M, Challis CD, Conway GD, Dux R, Eriksson LG, Esposito B, Frigione D, Hennequin P, Giroud C, Hawkes N, Huysmans G, Imbeaux F, Joffrin E, Lomas P, Lotte P, Maget P, Mantsinen M, Moreau D, Rimini F, Riva M, Sarazin Y, Tresset G, Tuccillo AA, Zastrow KD. JET quasistationary internal-transport-barrier operation with active control of the pressure profile. PHYSICAL REVIEW LETTERS 2002; 88:145004. [PMID: 11955156 DOI: 10.1103/physrevlett.88.145004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2001] [Indexed: 05/23/2023]
Abstract
Quasistationary operation has been achieved on the Joint European Torus tokamak in internal-transport-barrier (ITB) scenarios, with the discharge time limited only by plant constraints. Full current drive was obtained over all the high performance phase by using lower hybrid current drive. For the first time feedback control on the total pressure and on the electron temperature profile was implemented by using, respectively, the neutral beams and the ion-cyclotron waves. Although impurity accumulation could be a problem in steady state ITBs, these experiments bring some elements to answer to it.
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Affiliation(s)
- F Crisanti
- Associazione EURATOM-ENEA sulla Fusione, Centro Ricerche Frascati, C.P. 65, 00044 Frascati, Italy
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24
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Huysmans GT, Hender TC, Hawkes NC, Litaudon X. MHD stability of advanced tokamak scenarios with reversed central current: an explanation of the "current hole". PHYSICAL REVIEW LETTERS 2001; 87:245002. [PMID: 11736509 DOI: 10.1103/physrevlett.87.245002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2001] [Indexed: 05/23/2023]
Abstract
A region of zero current density in the plasma center has been observed in the advanced tokamak scenarios with off-axis lower-hybrid current drive in the JET and JT-60U tokamak experiments. Significantly, the central current density does not become negative, although this is expected based on conventional current diffusion. In this paper, it is shown that the zero central current density and the absence of negative central current can be explained by the influence of a resistive kink magnetohydrodynamic instability.
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Affiliation(s)
- G T Huysmans
- Association Euratom-CEA, Cadarache, F13108, France
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25
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Fujita T, Oikawa T, Suzuki T, Ide S, Sakamoto Y, Koide Y, Hatae T, Naito O, Isayama A, Hayashi N, Shirai H. Plasma equilibrium and confinement in a tokamak with nearly zero central current density in JT-60U. PHYSICAL REVIEW LETTERS 2001; 87:245001. [PMID: 11736508 DOI: 10.1103/physrevlett.87.245001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2001] [Indexed: 05/23/2023]
Abstract
A high confinement equilibrium with nearly zero toroidal current in the central region (a "current hole") has been observed for the first time to persist stably for several seconds in the JT-60U tokamak. This observation indicates the possibility of stable tokamak operation without central toroidal current; the central current has previously been believed to be necessary in tokamaks. The radius of the current hole extended up to 40% of the plasma minor radius. It was observed that the current hole was formed by the increase of the off-axis noninductive current.
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Affiliation(s)
- T Fujita
- Japan Atomic Energy Research Institute, Naka Fusion Research Establishment, Naka-machi, Ibaraki-ken, Japan
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