1
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Marcer G, Khilkevitch E, Shevelev A, Croci G, Dal Molin A, Gorini G, Grosso G, Muraro A, Nocente M, Perelli Cippo E, Putignano O, Rebai M, Rigamonti D, de la Luna E, Garcia J, Kazakov Y, Kiptily V, Maslov M, Nave MFF, Ongena J, Tardocchi M. A new dedicated signal processing system for gamma-ray spectrometers in high power deuterium-tritium plasma scenarios in tokamaks. Rev Sci Instrum 2022; 93:093525. [PMID: 36182521 DOI: 10.1063/5.0101611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 08/19/2022] [Indexed: 06/16/2023]
Abstract
The most performant deuterium-tritium (DT) plasma discharges realized by the Joint European Torus (JET) tokamak in the recent DT campaign have produced neutron yields on the order of 1018 n/s. At such high neutron yields, gamma-ray spectroscopy measurements with scintillators are challenging as events from the neutron-induced background often dominate over the signal, leading to a significant fraction of pileup events and instability of the photodetector gain along with the consequent degradation of the reconstructed spectrum. Here, we describe the solutions adopted for the tangential lanthanum bromide spectrometer installed at JET. A data acquisition system with free streaming mode digitization capabilities for the entire duration of the discharge has been used to solve dead-time related issues and a data reconstruction code with pileup recovery and photodetector gain drift restoration has been implemented for off-line analysis of the data. This work focuses on the acquired data storage and parsing, with a detailed explanation of the pileup recovery and gain drift restoration algorithms.
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Affiliation(s)
- G Marcer
- Department of Physics, University of Milan-Bicocca, Milan, Italy
| | | | - A Shevelev
- Ioffe Institute, St. Petersburg, Russian Federation
| | - G Croci
- Department of Physics, University of Milan-Bicocca, Milan, Italy
| | - A Dal Molin
- Institute for Plasma Science and Technology, CNR, Milan, Italy
| | - G Gorini
- Department of Physics, University of Milan-Bicocca, Milan, Italy
| | - G Grosso
- Institute for Plasma Science and Technology, CNR, Milan, Italy
| | - A Muraro
- Institute for Plasma Science and Technology, CNR, Milan, Italy
| | - M Nocente
- Department of Physics, University of Milan-Bicocca, Milan, Italy
| | - E Perelli Cippo
- Institute for Plasma Science and Technology, CNR, Milan, Italy
| | - O Putignano
- Department of Physics, University of Milan-Bicocca, Milan, Italy
| | - M Rebai
- Institute for Plasma Science and Technology, CNR, Milan, Italy
| | - D Rigamonti
- Institute for Plasma Science and Technology, CNR, Milan, Italy
| | - E de la Luna
- Laboratorio Nacional de Fusión, CIEMAT, Madrid, Spain
| | - J Garcia
- CEA, IRFM, Saint-Paul-lez-Durance, France
| | - Y Kazakov
- Laboratory for Plasma Physics, ERM/KMS, Brussels, Belgium
| | - V Kiptily
- Culham Centre for Fusion Energy, United Kingdom Atomic Energy Authority, Abingdon, United Kingdom
| | - M Maslov
- Culham Centre for Fusion Energy, United Kingdom Atomic Energy Authority, Abingdon, United Kingdom
| | - M F F Nave
- Associacao EURATOM/IST, Universidade Tecnica de Lisboa, Lisbon, Portugal
| | - J Ongena
- Laboratory for Plasma Physics, ERM/KMS, Brussels, Belgium
| | - M Tardocchi
- Institute for Plasma Science and Technology, CNR, Milan, Italy
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2
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Nocente M, Kiptily V, Tardocchi M, Bonofiglo PJ, Craciunescu T, Molin AD, De La Luna E, Eriksson J, Garcia J, Ghani Z, Gorini G, Hägg L, Kazakov Y, Lerche E, Maggi CF, Mantica P, Marcer G, Maslov M, Putignano O, Rigamonti D, Salewski M, Sharapov S, Siren P, Stancar Z, Zohar A, Beaumont P, Crombe K, Ericsson G, Garcia-Munoz M, Keeling D, King D, Kirov K, Nave MFF, Ongena J, Patel A, Perez von Thun C. Fusion product measurements by nuclear diagnostics in the Joint European Torus deuterium-tritium 2 campaign (invited). Rev Sci Instrum 2022; 93:093520. [PMID: 36182523 DOI: 10.1063/5.0101767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 08/20/2022] [Indexed: 06/16/2023]
Abstract
A new deuterium-tritium experimental, DTE2, campaign has been conducted at the Joint European Torus (JET) between August 2021 and late December 2021. Motivated by significant enhancements in the past decade at JET, such as the ITER-like wall and enhanced auxiliary heating power, the campaign achieved a new fusion energy world record and performed a broad range of fundamental experiments to inform ITER physics scenarios and operations. New capabilities in the area of fusion product measurements by nuclear diagnostics were available as a result of a decade long enhancement program. These have been tested for the first time in DTE2 and a concise overview is provided here. Confined alpha particle measurements by gamma-ray spectroscopy were successfully demonstrated, albeit with limitations at neutron rates higher than some 1017 n/s. High resolution neutron spectroscopy measurements with the magnetic proton recoil instrument were complemented by novel data from a set of synthetic diamond detectors, which enabled studies of the supra-thermal contributions to the neutron emission. In the area of escaping fast ion diagnostics, a lost fast ion detector and a set of Faraday cups made it possible to determine information on the velocity space and poloidal distribution of the lost alpha particles for the first time. This extensive set of data provides unique information for fundamental physics studies and validation of the numerical models, which are key to inform the physics and scenarios of ITER.
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Affiliation(s)
- M Nocente
- Department of Physics, University of Milano-Bicocca, Milan 20126, Italy
| | - V Kiptily
- United Kingdom Atomic Energy Authority, Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - M Tardocchi
- Institute for Plasma Science and Technology, National Research Council, Milan 20125, Italy
| | - P J Bonofiglo
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - T Craciunescu
- Institute of Atomic Physics, Magurele-Bucharest 077125, Romania
| | - A Dal Molin
- Institute for Plasma Science and Technology, National Research Council, Milan 20125, Italy
| | - E De La Luna
- Laboratorio Nacional de Fusión, CIEMAT, Madrid 28040, Spain
| | - J Eriksson
- Department of Physics and Astronomy, Uppsala University, Uppsala SE-75120, Sweden
| | - J Garcia
- CEA, IRFM, Saint Paul lez Durance 13115, France
| | - Z Ghani
- United Kingdom Atomic Energy Authority, Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - G Gorini
- Department of Physics, University of Milano-Bicocca, Milan 20126, Italy
| | - L Hägg
- Department of Physics and Astronomy, Uppsala University, Uppsala SE-75120, Sweden
| | - Y Kazakov
- Laboratory for Plasma Physics, LPP ERM/KMS, Brussels 1000, Belgium
| | - E Lerche
- Laboratory for Plasma Physics, LPP ERM/KMS, Brussels 1000, Belgium
| | - C F Maggi
- United Kingdom Atomic Energy Authority, Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - P Mantica
- Institute for Plasma Science and Technology, National Research Council, Milan 20125, Italy
| | - G Marcer
- Department of Physics, University of Milano-Bicocca, Milan 20126, Italy
| | - M Maslov
- United Kingdom Atomic Energy Authority, Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - O Putignano
- Department of Physics, University of Milano-Bicocca, Milan 20126, Italy
| | - D Rigamonti
- Institute for Plasma Science and Technology, National Research Council, Milan 20125, Italy
| | - M Salewski
- Department of Physics, Technical University of Denmark, Kgs. Lyngby 2800, Denmark
| | - S Sharapov
- United Kingdom Atomic Energy Authority, Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - P Siren
- United Kingdom Atomic Energy Authority, Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - Z Stancar
- United Kingdom Atomic Energy Authority, Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - A Zohar
- Jožef Stefan Institute, Ljubljana 1000, Slovenia
| | - P Beaumont
- United Kingdom Atomic Energy Authority, Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - K Crombe
- Laboratory for Plasma Physics, LPP ERM/KMS, Brussels 1000, Belgium
| | - G Ericsson
- Department of Physics and Astronomy, Uppsala University, Uppsala SE-75120, Sweden
| | - M Garcia-Munoz
- Department of Atomic, Molecular and Nuclear Physics, University of Seville, Seville 41012, Spain
| | - D Keeling
- United Kingdom Atomic Energy Authority, Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - D King
- United Kingdom Atomic Energy Authority, Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - K Kirov
- United Kingdom Atomic Energy Authority, Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - M F F Nave
- Instituto de Plasmas e Fusao Nuclear, IST, Universidade de Lisboa, Lisboa 1049-001, Portugal
| | - J Ongena
- Laboratory for Plasma Physics, LPP ERM/KMS, Brussels 1000, Belgium
| | - A Patel
- United Kingdom Atomic Energy Authority, Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - C Perez von Thun
- Institute of Plasma Physics and Laser Microfusion, Warsaw 01-497, Poland
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3
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Bernardo J, Nave MFF, Giroud C, Reyes Cortes S, Bizarro JPS. Ion temperature and toroidal rotation in JET's low torque plasmas. Rev Sci Instrum 2016; 87:11E557. [PMID: 27910313 DOI: 10.1063/1.4963714] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This paper reports on the procedure developed as the best method to provide an accurate and reliable estimation of the ion temperature Ti and the toroidal velocity vϕ from Charge-eXchange Recombination Spectroscopy (CXRS) data from intrinsic rotation experiments at the Joint European Torus with the carbon wall. The low impurity content observed in such plasmas, resulting in low active CXRS signal, alongside low Doppler shifts makes the determination of Ti and vϕ particularly difficult. The beam modulation method will be discussed along with the measures taken to increase photon statistics and minimise errors from the absolute calibration and magneto-hydro-dynamics effects that may impact the CXRS passive emission.
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Affiliation(s)
- J Bernardo
- Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - M F F Nave
- Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - C Giroud
- Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB, United Kingdom
| | - S Reyes Cortes
- Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - João P S Bizarro
- Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
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4
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Rice JE, Podpaly YA, Reinke ML, Mumgaard R, Scott SD, Shiraiwa S, Wallace GM, Chouli B, Fenzi-Bonizec C, Nave MFF, Diamond PH, Gao C, Granetz RS, Hughes JW, Parker RR, Bonoli PT, Delgado-Aparicio L, Eriksson LG, Giroud C, Greenwald MJ, Hubbard AE, Hutchinson IH, Irby JH, Kirov K, Mailloux J, Marmar ES, Wolfe SM. Effects of magnetic shear on toroidal rotation in tokamak plasmas with lower hybrid current drive. Phys Rev Lett 2013; 111:125003. [PMID: 24093268 DOI: 10.1103/physrevlett.111.125003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Indexed: 06/02/2023]
Abstract
Application of lower hybrid (LH) current drive in tokamak plasmas can induce both co- and countercurrent directed changes in toroidal rotation, depending on the core q profile. For discharges with q(0) <1, rotation increments in the countercurrent direction are observed. If the LH-driven current is sufficient to suppress sawteeth and increase q(0) above unity, the core toroidal rotation change is in the cocurrent direction. This change in sign of the rotation increment is consistent with a change in sign of the residual stress (the divergence of which constitutes an intrinsic torque that drives the flow) through its dependence on magnetic shear.
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Affiliation(s)
- J E Rice
- PSFC MIT, Cambridge, Massachusetts 02139, USA
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5
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Barnes M, Parra FI, Lee JP, Belli EA, Nave MFF, White AE. Intrinsic rotation driven by non-Maxwellian equilibria in Tokamak plasmas. Phys Rev Lett 2013; 111:055005. [PMID: 23952414 DOI: 10.1103/physrevlett.111.055005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Indexed: 06/02/2023]
Abstract
The effect of small deviations from a Maxwellian equilibrium on turbulent momentum transport in tokamak plasmas is considered. These non-Maxwellian features, arising from diamagnetic effects, introduce a strong dependence of the radial flux of cocurrent toroidal angular momentum on collisionality: As the plasma goes from nearly collisionless to weakly collisional, the flux reverses direction from radially inward to outward. This indicates a collisionality-dependent transition from peaked to hollow rotation profiles, consistent with experimental observations of intrinsic rotation.
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Affiliation(s)
- M Barnes
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02138, USA
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6
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Parra FI, Nave MFF, Schekochihin AA, Giroud C, de Grassie JS, Severo JHF, de Vries P, Zastrow KD. Scaling of spontaneous rotation with temperature and plasma current in tokamaks. Phys Rev Lett 2012; 108:095001. [PMID: 22463645 DOI: 10.1103/physrevlett.108.095001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Indexed: 05/31/2023]
Abstract
Using theoretical arguments, a simple scaling law for the size of the intrinsic rotation observed in tokamaks in the absence of a momentum injection is found: The velocity generated in the core of a tokamak must be proportional to the ion temperature difference in the core divided by the plasma current, independent of the size of the device. The constant of proportionality is of the order of 10 km·s(-1)·MA·keV(-1). When the intrinsic rotation profile is hollow, i.e., it is countercurrent in the core of the tokamak and cocurrent in the edge, the scaling law presented in this Letter fits the data remarkably well for several tokamaks of vastly different size and heated by different mechanisms.
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Affiliation(s)
- F I Parra
- Rudolf Peierls Centre for Theoretical Physics, University of Oxford, Oxford OX1 3NP, UK.
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7
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Nave MFF, Johnson T, Eriksson LG, Crombé K, Giroud C, Mayoral ML, Ongena J, Salmi A, Tala T, Tsalas M. Influence of magnetic field ripple on the intrinsic rotation of tokamak plasmas. Phys Rev Lett 2010; 105:105005. [PMID: 20867528 DOI: 10.1103/physrevlett.105.105005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Indexed: 05/29/2023]
Abstract
Using the unique capability of JET to monotonically change the amplitude of the magnetic field ripple, without modifying other relevant equilibrium conditions, the effect of the ripple on the angular rotation frequency of the plasma column was investigated under the conditions of no external momentum input. The ripple amplitude was varied from 0.08% to 1.5% in Ohmic and ion-cyclotron radio-frequency (ICRF) heated plasmas. In both cases the ripple causes counterrotation, indicating a strong torque due to nonambipolar transport of thermal ions and in the case of ICRF also fast ions.
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Affiliation(s)
- M F F Nave
- Associação EURATOM/IST, Instituto de Plasmas e Fusão Nuclear-Laboratorio Associado, Lisbon, Portugal
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8
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Solano ER, Lomas PJ, Alper B, Xu GS, Andrew Y, Arnoux G, Boboc A, Barrera L, Belo P, Beurskens MNA, Brix M, Crombe K, de la Luna E, Devaux S, Eich T, Gerasimov S, Giroud C, Harting D, Howell D, Huber A, Kocsis G, Korotkov A, Lopez-Fraguas A, Nave MFF, Rachlew E, Rimini F, Saarelma S, Sirinelli A, Pinches SD, Thomsen H, Zabeo L, Zarzoso D. Observation of confined current ribbon in JET plasmas. Phys Rev Lett 2010; 104:185003. [PMID: 20482186 DOI: 10.1103/physrevlett.104.185003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Indexed: 05/29/2023]
Abstract
We report the identification of a localized current structure inside the JET plasma. It is a field-aligned closed helical ribbon, carrying current in the same direction as the background current profile (cocurrent), rotating toroidally with the ion velocity (corotating). It appears to be located at a flat spot in the plasma pressure profile, at the top of the pedestal. The structure appears spontaneously in low density, high rotation plasmas, and can last up to 1.4 s, a time comparable to a local resistive time. It considerably delays the appearance of the first edge localized mode.
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Affiliation(s)
- E R Solano
- Laboratorio Nacional de Fusión, Asociación EURATOM-CIEMAT, 28040, Madrid, Spain
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9
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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. Phys Rev Lett 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] [What about the content of this article? (0)] [Affiliation(s)] [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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10
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Sauter O, Westerhof E, Mayoral ML, Alper B, Belo PA, Buttery RJ, Gondhalekar A, Hellsten T, Hender TC, Howell DF, Johnson T, Lamalle P, Mantsinen MJ, Milani F, Nave MFF, Nguyen F, Pecquet AL, Pinches SD, Podda S, Rapp J. Control of neoclassical tearing modes by sawtooth control. Phys Rev Lett 2002; 88:105001. [PMID: 11909362 DOI: 10.1103/physrevlett.88.105001] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2001] [Indexed: 05/23/2023]
Abstract
The onset of a neoclassical tearing mode (NTM) depends on the existence of a large enough seed island. It is shown in the Joint European Torus that NTMs can be readily destabilized by long-period sawteeth, such as obtained by sawtooth stabilization from ion-cyclotron heating or current drive. This has important implications for burning plasma scenarios, as alpha particles strongly stabilize the sawteeth. It is also shown that, by adding heating and current drive just outside the inversion radius, sawteeth are destabilized, resulting in shorter sawtooth periods and larger beta values being obtained without NTMs.
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Affiliation(s)
- O Sauter
- Centre de Recherches en Physique des Plasmas, Ass. EURATOM-Confédération Suisse, EPFL, 1015 Lausanne, Switzerland
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