1
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Kim SK, Shousha R, Yang SM, Hu Q, Hahn SH, Jalalvand A, Park JK, Logan NC, Nelson AO, Na YS, Nazikian R, Wilcox R, Hong R, Rhodes T, Paz-Soldan C, Jeon YM, Kim MW, Ko WH, Lee JH, Battey A, Yu G, Bortolon A, Snipes J, Kolemen E. Highest fusion performance without harmful edge energy bursts in tokamak. Nat Commun 2024; 15:3990. [PMID: 38734685 PMCID: PMC11088687 DOI: 10.1038/s41467-024-48415-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 04/29/2024] [Indexed: 05/13/2024] Open
Abstract
The path of tokamak fusion and International thermonuclear experimental reactor (ITER) is maintaining high-performance plasma to produce sufficient fusion power. This effort is hindered by the transient energy burst arising from the instabilities at the boundary of plasmas. Conventional 3D magnetic perturbations used to suppress these instabilities often degrade fusion performance and increase the risk of other instabilities. This study presents an innovative 3D field optimization approach that leverages machine learning and real-time adaptability to overcome these challenges. Implemented in the DIII-D and KSTAR tokamaks, this method has consistently achieved reactor-relevant core confinement and the highest fusion performance without triggering damaging bursts. This is enabled by advances in the physics understanding of self-organized transport in the plasma edge and machine learning techniques to optimize the 3D field spectrum. The success of automated, real-time adaptive control of such complex systems paves the way for maximizing fusion efficiency in ITER and beyond while minimizing damage to device components.
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Affiliation(s)
- S K Kim
- Princeton Plasma Physics Laboratory, Princeton, NJ, USA
| | - R Shousha
- Princeton Plasma Physics Laboratory, Princeton, NJ, USA
| | - S M Yang
- Princeton Plasma Physics Laboratory, Princeton, NJ, USA
| | - Q Hu
- Princeton Plasma Physics Laboratory, Princeton, NJ, USA
| | - S H Hahn
- Korea Institute of Fusion Energy, Daejeon, South Korea
| | | | - J-K Park
- Seoul National University, Seoul, South Korea
| | - N C Logan
- Columbia University, New York, NY, USA
| | | | - Y-S Na
- Seoul National University, Seoul, South Korea
| | | | - R Wilcox
- Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - R Hong
- University of California Los Angeles, Los Angeles, CA, USA
| | - T Rhodes
- University of California Los Angeles, Los Angeles, CA, USA
| | | | - Y M Jeon
- Korea Institute of Fusion Energy, Daejeon, South Korea
| | - M W Kim
- Korea Institute of Fusion Energy, Daejeon, South Korea
| | - W H Ko
- Korea Institute of Fusion Energy, Daejeon, South Korea
| | - J H Lee
- Korea Institute of Fusion Energy, Daejeon, South Korea
| | - A Battey
- Columbia University, New York, NY, USA
| | - G Yu
- University of California Davis, Davis, CA, USA
| | - A Bortolon
- Princeton Plasma Physics Laboratory, Princeton, NJ, USA
| | - J Snipes
- Princeton Plasma Physics Laboratory, Princeton, NJ, USA
| | - E Kolemen
- Princeton Plasma Physics Laboratory, Princeton, NJ, USA.
- Princeton University, Princeton, NJ, USA.
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2
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Yang S, Park JK, Jeon Y, Logan NC, Lee J, Hu Q, Lee J, Kim S, Kim J, Lee H, Na YS, Hahm TS, Choi G, Snipes JA, Park G, Ko WH. Tailoring tokamak error fields to control plasma instabilities and transport. Nat Commun 2024; 15:1275. [PMID: 38341448 DOI: 10.1038/s41467-024-45454-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 01/23/2024] [Indexed: 02/12/2024] Open
Abstract
A tokamak relies on the axisymmetric magnetic fields to confine fusion plasmas and aims to deliver sustainable and clean energy. However, misalignments arise inevitably in the tokamak construction, leading to small asymmetries in the magnetic field known as error fields (EFs). The EFs have been a major concern in the tokamak approaches because small EFs, even less than 0.1%, can drive a plasma disruption. Meanwhile, the EFs in the tokamak can be favorably used for controlling plasma instabilities, such as edge-localized modes (ELMs). Here we show an optimization that tailors the EFs to maintain an edge 3D response for ELM control with a minimized core 3D response to avoid plasma disruption and unnecessary confinement degradation. We design and demonstrate such an edge-localized 3D response in the KSTAR facility, benefiting from its unique flexibility to change many degrees of freedom in the 3D coil space for the various fusion plasma regimes. This favorable control of the tokamak EF represents a notable advance for designing intrinsically 3D tokamaks to optimize stability and confinement for next-step fusion reactors.
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Affiliation(s)
- SeongMoo Yang
- Princeton Plasma Physics Laboratory, Princeton, NJ, 08543, USA.
| | - Jong-Kyu Park
- Princeton Plasma Physics Laboratory, Princeton, NJ, 08543, USA
- Department of Nuclear Engineering, Seoul National University, Seoul, 08826, South Korea
| | - YoungMu Jeon
- Korea Institute of Fusion Energy, Daejeon, Republic of Korea
| | | | - Jaehyun Lee
- Korea Institute of Fusion Energy, Daejeon, Republic of Korea
| | - Qiming Hu
- Princeton Plasma Physics Laboratory, Princeton, NJ, 08543, USA
| | - JongHa Lee
- Korea Institute of Fusion Energy, Daejeon, Republic of Korea
| | - SangKyeun Kim
- Princeton Plasma Physics Laboratory, Princeton, NJ, 08543, USA
| | - Jaewook Kim
- Korea Institute of Fusion Energy, Daejeon, Republic of Korea
| | - Hyungho Lee
- Korea Institute of Fusion Energy, Daejeon, Republic of Korea
| | - Yong-Su Na
- Department of Nuclear Engineering, Seoul National University, Seoul, 08826, South Korea
| | - Taik Soo Hahm
- Department of Nuclear Engineering, Seoul National University, Seoul, 08826, South Korea
| | - Gyungjin Choi
- Department of Nuclear Engineering, Seoul National University, Seoul, 08826, South Korea
| | - Joseph A Snipes
- Princeton Plasma Physics Laboratory, Princeton, NJ, 08543, USA
| | - Gunyoung Park
- Korea Institute of Fusion Energy, Daejeon, Republic of Korea
| | - Won-Ha Ko
- Korea Institute of Fusion Energy, Daejeon, Republic of Korea
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3
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Gonzalez-Martin J, Garcia-Munoz M, Galdon-Quiroga J, Todo Y, Dominguez-Palacios J, Dunne M, van Vuuren AJ, Liu YQ, Sanchis L, Spong D, Suttrop W, Wang X, Willensdorfer M. Active Control of Alfvén Eigenmodes by Externally Applied 3D Magnetic Perturbations. PHYSICAL REVIEW LETTERS 2023; 130:035101. [PMID: 36763388 DOI: 10.1103/physrevlett.130.035101] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 09/27/2022] [Accepted: 12/19/2022] [Indexed: 06/18/2023]
Abstract
The suppression and excitation of Alfvén eigenmodes have been experimentally obtained, for the first time, by means of externally applied 3D perturbative fields with different spatial spectra in a tokamak plasma. The applied perturbation causes an internal fast-ion redistribution that modifies the phase-space gradients responsible for driving the modes, determining, ultimately their existence. Hybrid kinetic-magnetohydrodynamic simulations reveal an edge resonant transport layer activated by the 3D perturbative field as the responsible mechanism for the fast-ion redistribution. The results presented here may help to control fast-ion driven Alfvénic instabilities in future burning plasmas with a significant fusion born alpha particle population.
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Affiliation(s)
- J Gonzalez-Martin
- Department of Mechanical Engineering and Manufacturing, University of Seville, Camino de los Descubrimientos s/n, 41092 Seville, Spain
- Department of Physics and Astronomy, University of California, Irvine, California 92697, USA
| | - M Garcia-Munoz
- Department of Atomic, Molecular and Nuclear Physics, University of Seville, 41012 Seville, Spain
| | - J Galdon-Quiroga
- Department of Atomic, Molecular and Nuclear Physics, University of Seville, 41012 Seville, Spain
| | - Y Todo
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - J Dominguez-Palacios
- Department of Atomic, Molecular and Nuclear Physics, University of Seville, 41012 Seville, Spain
| | - M Dunne
- Max Planck Institute for Plasma Physics, Boltzmannstrasse, 2 85748 Garching bei Munchen, Germany
| | - A Jansen van Vuuren
- Department of Atomic, Molecular and Nuclear Physics, University of Seville, 41012 Seville, Spain
| | - Y Q Liu
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA
| | - L Sanchis
- Department of Applied Physics, Aalto University, FI-00076, Aalto, Finland
| | - D Spong
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - W Suttrop
- Max Planck Institute for Plasma Physics, Boltzmannstrasse, 2 85748 Garching bei Munchen, Germany
| | - X Wang
- Max Planck Institute for Plasma Physics, Boltzmannstrasse, 2 85748 Garching bei Munchen, Germany
| | - M Willensdorfer
- Max Planck Institute for Plasma Physics, Boltzmannstrasse, 2 85748 Garching bei Munchen, Germany
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4
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Plasma response impact on RMP divertor footprint modeling for KSTAR. NUCLEAR MATERIALS AND ENERGY 2023. [DOI: 10.1016/j.nme.2023.101380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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5
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Viezzer E, Austin M, Bernert M, Burrell K, Cano-Megias P, Chen X, Cruz-Zabala D, Coda S, Faitsch M, Fevrier O, Gil L, Giroud C, Happel T, Harrer G, Hubbard A, Hughes J, Kallenbach A, Labit B, Merle A, Meyer H, Paz-Soldan C, Oyola P, Sauter O, Siccinio M, Silvagni D, Solano E. Prospects of core–edge integrated no-ELM and small-ELM scenarios for future fusion devices. NUCLEAR MATERIALS AND ENERGY 2022. [DOI: 10.1016/j.nme.2022.101308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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6
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Modeling on the divertor power deposition in EAST discharges with magnetic perturbations induced by lower hybrid waves via the field-line diffusion model. FUSION ENGINEERING AND DESIGN 2021. [DOI: 10.1016/j.fusengdes.2021.112962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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7
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Progress of Divertor Heat and Particle Flux Control in EAST for Advanced Steady-State Operation in the Last 10 Years. JOURNAL OF FUSION ENERGY 2021. [DOI: 10.1007/s10894-021-00290-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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8
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Park JK, Yang SM, Logan NC, Hu Q, Zhu C, Zarnstorff MC, Nazikian R, Paz-Soldan C, Jeon YM, Ko WH. Quasisymmetric Optimization of Nonaxisymmetry in Tokamaks. PHYSICAL REVIEW LETTERS 2021; 126:125001. [PMID: 33834790 DOI: 10.1103/physrevlett.126.125001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 12/02/2020] [Accepted: 01/25/2021] [Indexed: 06/12/2023]
Abstract
Predictive 3D optimization reveals a novel approach to modify a nonaxisymmetric magnetic perturbation to be entirely harmless for tokamaks, by essentially restoring quasisymmetry in perturbed particle orbits as much as possible. Such a quasisymmetric magnetic perturbation (QSMP) has been designed and successfully tested in the KSTAR and DIII-D tokamaks, demonstrating no performance degradation despite the large overall amplitudes of nonaxisymmetric fields and strong response otherwise expected in the tested plasmas. The results indicate that a quasisymmetric optimization is a robust path of error field correction across the resonant and nonresonant field spectrum in a tokamak, leveraging the prevailing concept of quasisymmetry for general 3D plasma confinement systems such as stellarators. The optimization becomes, in fact, a simple eigenvalue problem to the so-called torque response matrices if a perturbed equilibrium is calculated consistent with nonaxisymmetric neoclassical transport.
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Affiliation(s)
- J-K Park
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - S M Yang
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - N C Logan
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - Q Hu
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - C Zhu
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - M C Zarnstorff
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - R Nazikian
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - C Paz-Soldan
- General Atomics, San Diego, California 92121, USA
| | - Y M Jeon
- National Fusion Research Institute, Daejeon 305-333, Republic of Korea
| | - W H Ko
- National Fusion Research Institute, Daejeon 305-333, Republic of Korea
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9
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A neutronics probe ball method on tritium generation rate simulation for a nuclear fusion reactor blanket. FUSION ENGINEERING AND DESIGN 2021. [DOI: 10.1016/j.fusengdes.2020.112117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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10
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Overview of the Recent Study on ELM Mitigation Physics with Different External Actuators on HL-2A Tokamak. JOURNAL OF FUSION ENERGY 2021. [DOI: 10.1007/s10894-021-00281-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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11
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Error field correction strategies in preparation to MAST-U operation. FUSION ENGINEERING AND DESIGN 2020. [DOI: 10.1016/j.fusengdes.2020.111932] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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12
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Frerichs H, Schmitz O, Bonnin X, Loarte A, Feng Y, Li L, Liu YQ, Reiter D. Detachment in Fusion Plasmas with Symmetry Breaking Magnetic Perturbation Fields. PHYSICAL REVIEW LETTERS 2020; 125:155001. [PMID: 33095602 DOI: 10.1103/physrevlett.125.155001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 06/24/2020] [Accepted: 09/09/2020] [Indexed: 06/11/2023]
Abstract
Power exhaust from the bulk plasma is significantly altered by symmetry breaking magnetic perturbation fields, because these create direct connections (perturbed field lines) from the confined high temperature plasma to solid surfaces. The same amount of power is distributed among those new exhaust channels as for a symmetric magnetic configuration, which reduces the local upstream heat flux flowing down the perturbed field lines, thereby making access to detachment easier (i.e., at lower upstream density) for the divertor plasma near the location corresponding to the symmetric magnetic separatrix. However, the divertor plasma regions with connection to the bulk plasma are extended nonaxisymmetrically further outside, where significant heat loads occur, unlike in the symmetric configuration. The temperature remains high at those locations, which reduces the divertor plasma dissipation capacity, making the mitigation of heat loads more difficult to achieve.
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Affiliation(s)
- H Frerichs
- Department of Engineering Physics, University of Wisconsin, Madison, Wisconsin 53706, USA
| | - O Schmitz
- Department of Engineering Physics, University of Wisconsin, Madison, Wisconsin 53706, USA
| | - X Bonnin
- ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex, France
| | - A Loarte
- ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex, France
| | - Y Feng
- Max-Planck-Institut für Plasmaphysik, Association EURATOM-IPP, 17491 Greifswald, Germany
| | - L Li
- College of Science, Donghua University, Shanghai 201620, People's Republic of China
| | - Y Q Liu
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA
| | - D Reiter
- Institute for Laser and Plasma Physics, Heinrich-Heine-University, D-40225 Duesseldorf, Germany
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13
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Hu QM, Nazikian R, Grierson BA, Logan NC, Orlov DM, Paz-Soldan C, Yu Q. Wide Operational Windows of Edge-Localized Mode Suppression by Resonant Magnetic Perturbations in the DIII-D Tokamak. PHYSICAL REVIEW LETTERS 2020; 125:045001. [PMID: 32794790 DOI: 10.1103/physrevlett.125.045001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 04/09/2020] [Accepted: 06/17/2020] [Indexed: 06/11/2023]
Abstract
Edge-localized mode (ELM) suppression by resonant magnetic perturbations (RMPs) generally occurs over very narrow ranges of the plasma current (or magnetic safety factor q_{95}) in the DIII-D tokamak. However, wide q_{95} ranges of ELM suppression are needed for the safety and operational flexibility of ITER and future reactors. In DIII-D ITER similar shape plasmas with n=3 RMPs, the range of q_{95} for ELM suppression is found to increase with decreasing electron density. Nonlinear two-fluid MHD simulations reproduce the observed q_{95} windows of ELM suppression and the dependence on plasma density, based on the conditions for resonant field penetration at the top of the pedestal. When the RMP amplitude is close to the threshold for resonant field penetration, only narrow isolated magnetic islands form near the top of the pedestal, leading to narrow q_{95} windows of ELM suppression. However, as the threshold for field penetration decreases with decreasing density, resonant field penetration can take place over a wider range of q_{95}. For sufficiently low density (penetration threshold) multiple magnetic islands form near the top of the pedestal giving rise to continuous q_{95} windows of ELM suppression. The model predicts that wide q_{95} windows of ELM suppression can be achieved at substantially higher pedestal pressure in DIII-D by shifting to higher toroidal mode number (n=4) RMPs.
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Affiliation(s)
- Q M Hu
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543-0451, USA
| | - R Nazikian
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543-0451, USA
| | - B A Grierson
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543-0451, USA
| | - N C Logan
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543-0451, USA
| | - D M Orlov
- University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0417, USA
| | - C Paz-Soldan
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA
| | - Q Yu
- Max-Planck-Institut für Plasmaphysik, Garching 85748, Germany
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14
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Effect of magnetic perturbation fields on power decay length in EMC3-EIRENE simulations and comparison to experiment in ASDEX upgrade. NUCLEAR MATERIALS AND ENERGY 2019. [DOI: 10.1016/j.nme.2019.02.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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15
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Frerichs H, Bonnin X, Feng Y, Loarte A, Pitts R, Reiter D, Schmitz O. Stabilization of EMC3-EIRENE for detachment conditions and comparison to SOLPS-ITER. NUCLEAR MATERIALS AND ENERGY 2019. [DOI: 10.1016/j.nme.2018.11.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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16
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Xiang J, Chen R, Ming T, Xu G, Yang J, Wang Y, Lin X, Liu Z, Gu S, Ye M. Tomographic reconstruction for a tangentially viewing visible light imaging diagnostic on EAST. FUSION ENGINEERING AND DESIGN 2018. [DOI: 10.1016/j.fusengdes.2018.04.038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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17
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Teschke M, Arden N, Eixenberger H, Rott M, Schandrul M, Suttrop W. Optimizing BUSSARD: The new 16-phase inverter system of ASDEX upgrade. FUSION ENGINEERING AND DESIGN 2017. [DOI: 10.1016/j.fusengdes.2017.02.056] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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18
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Suárez López G, Ochoukov R, Willensdorfer M, Bobkov V, Dunne M, Faugel H, Fünfgelder H, Noterdaeme JM, Strumberger E, Suttrop W, Zohm H. Investigation of the coupling properties of the ion cyclotron fast wave under applied magnetic perturbations and MHD phenomena in ASDEX Upgrade. EPJ WEB OF CONFERENCES 2017. [DOI: 10.1051/epjconf/201715703051] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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19
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Brida D, Lunt T, Wischmeier M, Birkenmeier G, Cahyna P, Carralero D, Faitsch M, Feng Y, Kurzan B, Schubert M, Sieglin B, Suttrop W, Wolfrum E. Determination of the stochastic layer properties induced by magnetic perturbations via heat pulse experiments at ASDEX upgrade. NUCLEAR MATERIALS AND ENERGY 2017. [DOI: 10.1016/j.nme.2017.03.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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20
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Eich T, Sieglin B, Thornton A, Faitsch M, Kirk A, Herrmann A, Suttrop W. ELM divertor peak energy fluence scaling to ITER with data from JET, MAST and ASDEX upgrade. NUCLEAR MATERIALS AND ENERGY 2017. [DOI: 10.1016/j.nme.2017.04.014] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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21
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Faitsch M, Sieglin B, Eich T, Herrmann A, Suttrop W. 2D heat flux in ASDEX Upgrade L-Mode with magnetic perturbation. NUCLEAR MATERIALS AND ENERGY 2017. [DOI: 10.1016/j.nme.2017.03.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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22
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Sun Y, Liang Y, Liu YQ, Gu S, Yang X, Guo W, Shi T, Jia M, Wang L, Lyu B, Zhou C, Liu A, Zang Q, Liu H, Chu N, Wang HH, Zhang T, Qian J, Xu L, He K, Chen D, Shen B, Gong X, Ji X, Wang S, Qi M, Song Y, Yuan Q, Sheng Z, Gao G, Fu P, Wan B. Nonlinear Transition from Mitigation to Suppression of the Edge Localized Mode with Resonant Magnetic Perturbations in the EAST Tokamak. PHYSICAL REVIEW LETTERS 2016; 117:115001. [PMID: 27661697 DOI: 10.1103/physrevlett.117.115001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Indexed: 06/06/2023]
Abstract
Evidence of a nonlinear transition from mitigation to suppression of the edge localized mode (ELM) by using resonant magnetic perturbations (RMPs) in the EAST tokamak is presented. This is the first demonstration of ELM suppression with RMPs in slowly rotating plasmas with dominant radio-frequency wave heating. Changes of edge magnetic topology after the transition are indicated by a gradual phase shift in the plasma response field from a linear magneto hydro dynamics modeling result to a vacuum one and a sudden increase of three-dimensional particle flux to the divertor. The transition threshold depends on the spectrum of RMPs and plasma rotation as well as perturbation amplitude. This means that edge topological changes resulting from nonlinear plasma response plays a key role in the suppression of ELM with RMPs.
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Affiliation(s)
- Y Sun
- Institute of Plasma Physics, Chinese Academy of Sciences, PO Box 1126, Hefei 230031, China
| | - Y Liang
- Institute of Plasma Physics, Chinese Academy of Sciences, PO Box 1126, Hefei 230031, China
- Institute for Energy and Climate Research-Plasma Physics, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Y Q Liu
- CCFE Culham Science Centre, Abingdon, OX14 3DB, United Kingdom
| | - S Gu
- Institute of Plasma Physics, Chinese Academy of Sciences, PO Box 1126, Hefei 230031, China
| | - X Yang
- School of Physics and Optoelectronic Engineering, Dalian University of Technology, Dalian 116024, China
| | - W Guo
- Institute of Plasma Physics, Chinese Academy of Sciences, PO Box 1126, Hefei 230031, China
| | - T Shi
- Institute of Plasma Physics, Chinese Academy of Sciences, PO Box 1126, Hefei 230031, China
| | - M Jia
- Institute of Plasma Physics, Chinese Academy of Sciences, PO Box 1126, Hefei 230031, China
| | - L Wang
- Institute of Plasma Physics, Chinese Academy of Sciences, PO Box 1126, Hefei 230031, China
| | - B Lyu
- Institute of Plasma Physics, Chinese Academy of Sciences, PO Box 1126, Hefei 230031, China
| | - C Zhou
- Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - A Liu
- Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Q Zang
- Institute of Plasma Physics, Chinese Academy of Sciences, PO Box 1126, Hefei 230031, China
| | - H Liu
- Institute of Plasma Physics, Chinese Academy of Sciences, PO Box 1126, Hefei 230031, China
| | - N Chu
- Institute of Plasma Physics, Chinese Academy of Sciences, PO Box 1126, Hefei 230031, China
| | - H H Wang
- Institute of Plasma Physics, Chinese Academy of Sciences, PO Box 1126, Hefei 230031, China
| | - T Zhang
- Institute of Plasma Physics, Chinese Academy of Sciences, PO Box 1126, Hefei 230031, China
| | - J Qian
- Institute of Plasma Physics, Chinese Academy of Sciences, PO Box 1126, Hefei 230031, China
| | - L Xu
- Institute of Plasma Physics, Chinese Academy of Sciences, PO Box 1126, Hefei 230031, China
| | - K He
- Institute of Plasma Physics, Chinese Academy of Sciences, PO Box 1126, Hefei 230031, China
| | - D Chen
- Institute of Plasma Physics, Chinese Academy of Sciences, PO Box 1126, Hefei 230031, China
| | - B Shen
- Institute of Plasma Physics, Chinese Academy of Sciences, PO Box 1126, Hefei 230031, China
| | - X Gong
- Institute of Plasma Physics, Chinese Academy of Sciences, PO Box 1126, Hefei 230031, China
| | - X Ji
- Institute of Plasma Physics, Chinese Academy of Sciences, PO Box 1126, Hefei 230031, China
| | - S Wang
- Institute of Plasma Physics, Chinese Academy of Sciences, PO Box 1126, Hefei 230031, China
| | - M Qi
- Institute of Plasma Physics, Chinese Academy of Sciences, PO Box 1126, Hefei 230031, China
| | - Y Song
- Institute of Plasma Physics, Chinese Academy of Sciences, PO Box 1126, Hefei 230031, China
| | - Q Yuan
- Institute of Plasma Physics, Chinese Academy of Sciences, PO Box 1126, Hefei 230031, China
| | - Z Sheng
- Institute of Plasma Physics, Chinese Academy of Sciences, PO Box 1126, Hefei 230031, China
| | - G Gao
- Institute of Plasma Physics, Chinese Academy of Sciences, PO Box 1126, Hefei 230031, China
| | - P Fu
- Institute of Plasma Physics, Chinese Academy of Sciences, PO Box 1126, Hefei 230031, China
| | - B Wan
- Institute of Plasma Physics, Chinese Academy of Sciences, PO Box 1126, Hefei 230031, China
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Lee J, Yun GS, Choi MJ, Kwon JM, Jeon YM, Lee W, Luhmann NC, Park HK. Nonlinear Interaction of Edge-Localized Modes and Turbulent Eddies in Toroidal Plasma under n=1 Magnetic Perturbation. PHYSICAL REVIEW LETTERS 2016; 117:075001. [PMID: 27563970 DOI: 10.1103/physrevlett.117.075001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Indexed: 06/06/2023]
Abstract
The effect of static n=1 resonant magnetic perturbation (RMP) on the spatial structure and temporal dynamics of edge-localized modes (ELMs) and edge turbulence in tokamak plasma has been investigated. Two-dimensional images measured by a millimeter-wave camera on the KSTAR tokamak revealed that the coherent filamentary modes (i.e., ELMs) are still present in the edge region when the usual large scale collapse of the edge confinement, i.e., the ELM crash, is completely suppressed by n=1 RMP. Cross-correlation analyses on the 2D images show that (1) the RMP enhances turbulent fluctuations in the edge toward the ELM-crash-suppression phase, (2) the induced turbulence has a clear dispersion relation for wide ranges of wave number and frequency, and (3) the turbulence involves a net radially outward energy transport. Nonlinear interactions of the turbulent eddies with the coexisting ELMs are clearly observed by bispectral analysis, which implies that the exchange of energy between them may be the key to the prevention of large scale crashes.
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Affiliation(s)
- Jaehyun Lee
- Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Gunsu S Yun
- Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Minjun J Choi
- National Fusion Research Institute, Daejeon 34133, Republic of Korea
| | - Jae-Min Kwon
- National Fusion Research Institute, Daejeon 34133, Republic of Korea
| | - Young-Mu Jeon
- National Fusion Research Institute, Daejeon 34133, Republic of Korea
| | - Woochang Lee
- Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | | | - Hyeon K Park
- Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
- National Fusion Research Institute, Daejeon 34133, Republic of Korea
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24
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Teschke M, Arden N, Eixenberger H, Rott M, Suttrop W. Electrical design of the BUSSARD inverter system for ASDEX upgrade saddle coils. FUSION ENGINEERING AND DESIGN 2015. [DOI: 10.1016/j.fusengdes.2015.06.157] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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25
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Nazikian R, Paz-Soldan C, Callen JD, deGrassie JS, Eldon D, Evans TE, Ferraro NM, Grierson BA, Groebner RJ, Haskey SR, Hegna CC, King JD, Logan NC, McKee GR, Moyer RA, Okabayashi M, Orlov DM, Osborne TH, Park JK, Rhodes TL, Shafer MW, Snyder PB, Solomon WM, Strait EJ, Wade MR. Pedestal bifurcation and resonant field penetration at the threshold of edge-localized mode suppression in the DIII-D Tokamak. PHYSICAL REVIEW LETTERS 2015; 114:105002. [PMID: 25815938 DOI: 10.1103/physrevlett.114.105002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Indexed: 06/04/2023]
Abstract
Rapid bifurcations in the plasma response to slowly varying n=2 magnetic fields are observed as the plasma transitions into and out of edge-localized mode (ELM) suppression. The rapid transition to ELM suppression is characterized by an increase in the toroidal rotation and a reduction in the electron pressure gradient at the top of the pedestal that reduces the perpendicular electron flow there to near zero. These events occur simultaneously with an increase in the inner-wall magnetic response. These observations are consistent with strong resonant field penetration of n=2 fields at the onset of ELM suppression, based on extended MHD simulations using measured plasma profiles. Spontaneous transitions into (and out of) ELM suppression with a static applied n=2 field indicate competing mechanisms of screening and penetration of resonant fields near threshold conditions. Magnetic measurements reveal evidence for the unlocking and rotation of tearinglike structures as the plasma transitions out of ELM suppression.
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Affiliation(s)
- R Nazikian
- Princeton Plasma Physics Laboratory, PO Box 451, Princeton, New Jersey 08543-0451, USA
| | - C Paz-Soldan
- General Atomics, PO Box 85608, San Diego, California 92186-5608, USA
| | - J D Callen
- University of Wisconsin-Madison, 1500 Engineering Drive, Madison, Wisconsin 53706-1609, USA
| | - J S deGrassie
- General Atomics, PO Box 85608, San Diego, California 92186-5608, USA
| | - D Eldon
- University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0417, USA
| | - T E Evans
- General Atomics, PO Box 85608, San Diego, California 92186-5608, USA
| | - N M Ferraro
- General Atomics, PO Box 85608, San Diego, California 92186-5608, USA
| | - B A Grierson
- Princeton Plasma Physics Laboratory, PO Box 451, Princeton, New Jersey 08543-0451, USA
| | - R J Groebner
- General Atomics, PO Box 85608, San Diego, California 92186-5608, USA
| | - S R Haskey
- Plasma Research Laboratory, Australian National University, Canberra, ACT 0200, Australia
| | - C C Hegna
- University of Wisconsin-Madison, 1500 Engineering Drive, Madison, Wisconsin 53706-1609, USA
| | - J D King
- General Atomics, PO Box 85608, San Diego, California 92186-5608, USA
| | - N C Logan
- Princeton Plasma Physics Laboratory, PO Box 451, Princeton, New Jersey 08543-0451, USA
| | - G R McKee
- University of Wisconsin-Madison, 1500 Engineering Drive, Madison, Wisconsin 53706-1609, USA
| | - R A Moyer
- University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0417, USA
| | - M Okabayashi
- Princeton Plasma Physics Laboratory, PO Box 451, Princeton, New Jersey 08543-0451, USA
| | - D M Orlov
- University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0417, USA
| | - T H Osborne
- General Atomics, PO Box 85608, San Diego, California 92186-5608, USA
| | - J-K Park
- Princeton Plasma Physics Laboratory, PO Box 451, Princeton, New Jersey 08543-0451, USA
| | - T L Rhodes
- University of California, Los Angeles, Los Angeles, California 90095, USA
| | - M W Shafer
- Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, Tennessee 37831, USA
| | - P B Snyder
- General Atomics, PO Box 85608, San Diego, California 92186-5608, USA
| | - W M Solomon
- Princeton Plasma Physics Laboratory, PO Box 451, Princeton, New Jersey 08543-0451, USA
| | - E J Strait
- General Atomics, PO Box 85608, San Diego, California 92186-5608, USA
| | - M R Wade
- General Atomics, PO Box 85608, San Diego, California 92186-5608, USA
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26
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Paz-Soldan C, Nazikian R, Haskey SR, Logan NC, Strait EJ, Ferraro NM, Hanson JM, King JD, Lanctot MJ, Moyer RA, Okabayashi M, Park JK, Shafer MW, Tobias BJ. Observation of a multimode plasma response and its relationship to density pumpout and edge-localized mode suppression. PHYSICAL REVIEW LETTERS 2015; 114:105001. [PMID: 25815937 DOI: 10.1103/physrevlett.114.105001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Indexed: 06/04/2023]
Abstract
Density pumpout and edge-localized mode (ELM) suppression by applied n=2 magnetic fields in low-collisionality DIII-D plasmas are shown to be correlated with the magnitude of the plasma response driven on the high-field side (HFS) of the magnetic axis but not the low-field side (LFS) midplane. These distinct responses are a direct measurement of a multimodal magnetic plasma response, with each structure preferentially excited by a different n=2 applied spectrum and preferentially detected on the LFS or HFS. Ideal and resistive magneto-hydrodynamic (MHD) calculations find that the LFS measurement is primarily sensitive to the excitation of stable kink modes, while the HFS measurement is primarily sensitive to resonant currents (whether fully shielding or partially penetrated). The resonant currents are themselves strongly modified by kink excitation, with the optimal applied field pitch for pumpout and ELM suppression significantly differing from equilibrium field alignment.
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Affiliation(s)
- C Paz-Soldan
- General Atomics, San Diego, California 92121, USA
| | - R Nazikian
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - S R Haskey
- Plasma Research Laboratory, Australian National University, Canberra, Australian Capital Territory 0200, Australia
| | - N C Logan
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - E J Strait
- General Atomics, San Diego, California 92121, USA
| | - N M Ferraro
- General Atomics, San Diego, California 92121, USA
| | - J M Hanson
- Columbia University, New York, New York 10027, USA
| | - J D King
- General Atomics, San Diego, California 92121, USA
| | - M J Lanctot
- General Atomics, San Diego, California 92121, USA
| | - R A Moyer
- University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0417, USA
| | - M Okabayashi
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - J-K Park
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - M W Shafer
- Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6169, USA
| | - B J Tobias
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
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27
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Hu JS, Sun Z, Guo HY, Li JG, Wan BN, Wang HQ, Ding SY, Xu GS, Liang YF, Mansfield DK, Maingi R, Zou XL, Wang L, Ren J, Zuo GZ, Zhang L, Duan YM, Shi TH, Hu LQ. New steady-state quiescent high-confinement plasma in an experimental advanced superconducting tokamak. PHYSICAL REVIEW LETTERS 2015; 114:055001. [PMID: 25699449 DOI: 10.1103/physrevlett.114.055001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Indexed: 06/04/2023]
Abstract
A critical challenge facing the basic long-pulse high-confinement operation scenario (H mode) for ITER is to control a magnetohydrodynamic (MHD) instability, known as the edge localized mode (ELM), which leads to cyclical high peak heat and particle fluxes at the plasma facing components. A breakthrough is made in the Experimental Advanced Superconducting Tokamak in achieving a new steady-state H mode without the presence of ELMs for a duration exceeding hundreds of energy confinement times, by using a novel technique of continuous real-time injection of a lithium (Li) aerosol into the edge plasma. The steady-state ELM-free H mode is accompanied by a strong edge coherent MHD mode (ECM) at a frequency of 35-40 kHz with a poloidal wavelength of 10.2 cm in the ion diamagnetic drift direction, providing continuous heat and particle exhaust, thus preventing the transient heat deposition on plasma facing components and impurity accumulation in the confined plasma. It is truly remarkable that Li injection appears to promote the growth of the ECM, owing to the increase in Li concentration and hence collisionality at the edge, as predicted by GYRO simulations. This new steady-state ELM-free H-mode regime, enabled by real-time Li injection, may open a new avenue for next-step fusion development.
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Affiliation(s)
- J S Hu
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Z Sun
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - H Y Guo
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, China and General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA
| | - J G Li
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - B N Wan
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - H Q Wang
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - S Y Ding
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - G S Xu
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Y F Liang
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, China and Forschungszentrum Jülich GmbH, Association EURATOM-FZ, Jülich D-52425, Germany
| | - D K Mansfield
- Princeton University Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - R Maingi
- Princeton University Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - X L Zou
- CEA, IRFM, F-13108 Saint-Paul-lez-Durance, France
| | - L Wang
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - J Ren
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - G Z Zuo
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - L Zhang
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Y M Duan
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - T H Shi
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - L Q Hu
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, China
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28
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Solomon WM, Snyder PB, Burrell KH, Fenstermacher ME, Garofalo AM, Grierson BA, Loarte A, McKee GR, Nazikian R, Osborne TH. Access to a new plasma edge state with high density and pressures using the quiescent H mode. PHYSICAL REVIEW LETTERS 2014; 113:135001. [PMID: 25302895 DOI: 10.1103/physrevlett.113.135001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Indexed: 06/04/2023]
Abstract
A path to a new high performance regime has been discovered in tokamaks that could improve the attractiveness of a fusion reactor. Experiments on DIII-D using a quiescent H-mode edge have navigated a valley of improved edge peeling-ballooning stability that opens up with strong plasma shaping at high density, leading to a doubling of the edge pressure over the standard H mode with edge localized modes at these parameters. The thermal energy confinement time increases as a result of both the increased pedestal height and improvements in the core transport and reduced low-k turbulence. Calculations of the pedestal height and width as a function of density using constraints imposed by peeling-ballooning and kinetic-ballooning theory are in quantitative agreement with the measurements.
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Affiliation(s)
- W M Solomon
- Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543, USA
| | - P B Snyder
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA
| | - K H Burrell
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA
| | - M E Fenstermacher
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, USA
| | - A M Garofalo
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA
| | - B A Grierson
- Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543, USA
| | - A Loarte
- ITER Organization, Route de Vinon sur Verdon, CS 90 046, 13067 Saint Paul Lez Durance Cedex, France
| | - G R McKee
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - R Nazikian
- Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543, USA
| | - T H Osborne
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA
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29
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Bécoulet M, Orain F, Huijsmans GTA, Pamela S, Cahyna P, Hoelzl M, Garbet X, Franck E, Sonnendrücker E, Dif-Pradalier G, Passeron C, Latu G, Morales J, Nardon E, Fil A, Nkonga B, Ratnani A, Grandgirard V. Mechanism of edge localized mode mitigation by resonant magnetic perturbations. PHYSICAL REVIEW LETTERS 2014; 113:115001. [PMID: 25259985 DOI: 10.1103/physrevlett.113.115001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Indexed: 06/03/2023]
Abstract
A possible mechanism of edge localized modes (ELMs) mitigation by resonant magnetic perturbations (RMPs) is proposed based on the results of nonlinear resistive magnetohydrodynamic modeling using the jorek code, realistic JET-like plasma parameters and an RMP spectrum of JET error-field correction coils (EFCC) with a main toroidal number n=2 were used in the simulations. Without RMPs, a large ELM relaxation is obtained mainly due to the most unstable medium-n ballooning mode. The externally imposed RMP drives nonlinearly the modes coupled to n=2 RMP which produce small multimode relaxations, mitigated ELMs. The modes driven by RMPs exhibit a tearinglike structure and produce additional islands. Mitigated ELMs deposit energy into the divertor mainly in the structures ("footprints") created by n=2 RMPs, however, slightly modulated by other nonlinearly driven even harmonics. The divertor power flux during a ELM phase mitigated by RMPs is reduced almost by a factor of 10. The mechanism of ELM mitigation by RMPs proposed here reproduces generic features of high collisionality RMP experiments, where large ELMs are replaced by small, much more frequent ELMs or magnetic turbulence. Total ELM suppression was also demonstrated in modeling at higher RMP amplitude.
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Affiliation(s)
- M Bécoulet
- CEA, IRFM, 13108 Saint-Paul-Lez-Durance, France
| | - F Orain
- CEA, IRFM, 13108 Saint-Paul-Lez-Durance, France
| | - G T A Huijsmans
- ITER Organization, Route de Vinon-sur-Verdon, 13067 Saint-Paul-Lez-Durance, France
| | - S Pamela
- CCFE, Culham Science Centre, Oxon OX14 3DB, United Kingdom
| | - P Cahyna
- Institute of Plasma Physics ASCR, 182 00 Prague 8, Czech Republic
| | - M Hoelzl
- Max-Planck-Institut, 85748 Garching, Germany
| | - X Garbet
- CEA, IRFM, 13108 Saint-Paul-Lez-Durance, France
| | - E Franck
- Max-Planck-Institut, 85748 Garching, Germany
| | | | | | - C Passeron
- CEA, IRFM, 13108 Saint-Paul-Lez-Durance, France
| | - G Latu
- CEA, IRFM, 13108 Saint-Paul-Lez-Durance, France
| | - J Morales
- CEA, IRFM, 13108 Saint-Paul-Lez-Durance, France
| | - E Nardon
- CEA, IRFM, 13108 Saint-Paul-Lez-Durance, France
| | - A Fil
- CEA, IRFM, 13108 Saint-Paul-Lez-Durance, France
| | - B Nkonga
- Laboratoire de Mathématiques J.A. Dieudonné, UMR 7351, CNRS UNS, Université de Nice-Sophia Antipolis, Parc Valrose, 06108 Nice Cedex 02, France
| | - A Ratnani
- Laboratoire de Mathématiques J.A. Dieudonné, UMR 7351, CNRS UNS, Université de Nice-Sophia Antipolis, Parc Valrose, 06108 Nice Cedex 02, France
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30
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The enhanced high speed inboard pellet fuelling system at ASDEX Upgrade. FUSION ENGINEERING AND DESIGN 2013. [DOI: 10.1016/j.fusengdes.2012.12.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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31
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Suttrop W, Fuchs J, Fischer R, Giannone L, Herrmann A, McDermott R, Maraschek M, Mlynek A, Müller H, Lang P, Pütterich T, Rott M, Vierle T, Viezzer E, Wolfrum E. Mitigation of edge localised modes with magnetic perturbations in ASDEX Upgrade. FUSION ENGINEERING AND DESIGN 2013. [DOI: 10.1016/j.fusengdes.2013.01.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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32
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Liang Y, Gong XZ, Gan KF, Gauthier E, Wang L, Rack M, Wang YM, Zeng L, Denner P, Wingen A, Lv B, Ding BJ, Chen R, Hu LQ, Hu JS, Liu FK, Jie YX, Pearson J, Qian JP, Shan JF, Shen B, Shi TH, Sun Y, Wang FD, Wang HQ, Wang M, Wu ZW, Zhang SB, Zhang T, Zhang XJ, Yan N, Xu GS, Guo HY, Wan BN, Li JG. Magnetic topology changes induced by lower hybrid waves and their profound effect on edge-localized modes in the EAST tokamak. PHYSICAL REVIEW LETTERS 2013; 110:235002. [PMID: 25167503 DOI: 10.1103/physrevlett.110.235002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2013] [Indexed: 06/03/2023]
Abstract
Strong mitigation of edge-localized modes has been observed on Experimental Advanced Superconducting Tokamak, when lower hybrid waves (LHWs) are applied to H-mode plasmas with ion cyclotron resonant heating. This has been demonstrated to be due to the formation of helical current filaments flowing along field lines in the scrape-off layer induced by LHW. This leads to the splitting of the outer divertor strike points during LHWs similar to previous observations with resonant magnetic perturbations. The change in the magnetic topology has been qualitatively modeled by considering helical current filaments in a field-line-tracing code.
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Affiliation(s)
- Y Liang
- Forschungszentrum Jülich GmbH, Association EURATOM-FZ Jülich, Institut für Energie und Klimaforschung Plasmaphysik, Trilateral Euregio Cluster, D-52425 Jülich, Germany
| | - X Z Gong
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - K F Gan
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - E Gauthier
- CEA, IRFM, F-13108 Saint-Paul-lez-Durance, France
| | - L Wang
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - M Rack
- Forschungszentrum Jülich GmbH, Association EURATOM-FZ Jülich, Institut für Energie und Klimaforschung Plasmaphysik, Trilateral Euregio Cluster, D-52425 Jülich, Germany
| | - Y M Wang
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - L Zeng
- Forschungszentrum Jülich GmbH, Association EURATOM-FZ Jülich, Institut für Energie und Klimaforschung Plasmaphysik, Trilateral Euregio Cluster, D-52425 Jülich, Germany and Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - P Denner
- Forschungszentrum Jülich GmbH, Association EURATOM-FZ Jülich, Institut für Energie und Klimaforschung Plasmaphysik, Trilateral Euregio Cluster, D-52425 Jülich, Germany
| | - A Wingen
- Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6169, USA
| | - B Lv
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - B J Ding
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - R Chen
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - L Q Hu
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - J S Hu
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - F K Liu
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - Y X Jie
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - J Pearson
- Forschungszentrum Jülich GmbH, Association EURATOM-FZ Jülich, Institut für Energie und Klimaforschung Plasmaphysik, Trilateral Euregio Cluster, D-52425 Jülich, Germany
| | - J P Qian
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - J F Shan
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - B Shen
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - T H Shi
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - Y Sun
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - F D Wang
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - H Q Wang
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - M Wang
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - Z W Wu
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - S B Zhang
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - T Zhang
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - X J Zhang
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - N Yan
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - G S Xu
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - H Y Guo
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - B N Wan
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - J G Li
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
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33
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Kim K, Park JK, Boozer AH. Numerical verification of bounce-harmonic resonances in neoclassical toroidal viscosity for tokamaks. PHYSICAL REVIEW LETTERS 2013; 110:185004. [PMID: 23683209 DOI: 10.1103/physrevlett.110.185004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Indexed: 06/02/2023]
Abstract
This Letter presents the first numerical verification for the bounce-harmonic (BH) resonance phenomena of the neoclassical transport in a tokamak perturbed by nonaxisymmetric magnetic fields. The BH resonances were predicted by analytic theories of neoclassical toroidal viscosity (NTV), as the parallel and perpendicular drift motions can be resonant and result in a great enhancement of the radial momentum transport. A new drift-kinetic δf guiding-center particle code, POCA, clearly verified that the perpendicular drift motions can reduce the transport by phase-mixing, but in the BH resonances the motions can form closed orbits and particles radially drift out fast. The POCA calculations on resulting NTV torque are largely consistent with analytic calculations, and show that the BH resonances can easily dominate the NTV torque when a plasma rotates in the perturbed tokamak and therefore, is a critical physics for predicting the rotation and stability in the International Thermonuclear Experimental Reactor.
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Affiliation(s)
- Kimin Kim
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA.
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34
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Takizuka T, Oyama N, Fukuda T. Resonant Magnetic Perturbation for ELM Suppression with Helical Ferritic Steel Inserts in Tokamak DEMO Reactor. FUSION SCIENCE AND TECHNOLOGY 2013. [DOI: 10.13182/fst13-a16875] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- T. Takizuka
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita 565-0871, Japan
| | - N. Oyama
- Naka Fusion Institute, Japan Atomic Energy Agency, 801-1 Mukoyama, Naka 311-0193, Japan
| | - T. Fukuda
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita 565-0871, Japan
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35
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Jeon YM, Park JK, Yoon SW, Ko WH, Lee SG, Lee KD, Yun GS, Nam YU, Kim WC, Kwak JG, Lee KS, Kim HK, Yang HL. Suppression of edge localized modes in high-confinement KSTAR plasmas by nonaxisymmetric magnetic perturbations. PHYSICAL REVIEW LETTERS 2012; 109:035004. [PMID: 22861864 DOI: 10.1103/physrevlett.109.035004] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2011] [Indexed: 06/01/2023]
Abstract
Edge localized modes (ELMs) in high-confinement mode plasmas were completely suppressed in KSTAR by applying n=1 nonaxisymmetric magnetic perturbations. Initially, the ELMs were intensified with a reduction of frequency, but completely suppressed later. The electron density had an initial 10% decrease followed by a gradual increase as ELMs were suppressed. Interesting phenomena such as a saturated evolution of edge T(e) and broadband changes of magnetic fluctuations were observed, suggesting the change of edge transport by the applied magnetic perturbations.
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Affiliation(s)
- Y M Jeon
- National Fusion Research Institute, Daejeon, Korea.
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36
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Kirk A, Harrison J, Liu Y, Nardon E, Chapman IT, Denner P. Observation of lobes near the X point in resonant magnetic perturbation experiments on MAST. PHYSICAL REVIEW LETTERS 2012; 108:255003. [PMID: 23004608 DOI: 10.1103/physrevlett.108.255003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Indexed: 06/01/2023]
Abstract
The application of nonaxisymmetric resonant magnetic perturbations (RMPs) with a toroidal mode number n = 6 in the MAST tokamak produces a significant reduction in plasma energy loss associated with type-I edge localized modes (ELMs), the first such observation with n > 3. During the ELM mitigated stage clear lobe structures are observed in visible-light imaging of the X-point region. These lobes or manifold structures, that were predicted previously, have been observed for the first time in a range of discharges and their appearance is correlated with the effect of RMPs on the plasma; i.e., they only appear above a threshold when a density pump out is observed or when the ELM frequency is increased. They appear to be correlated with the RMPs penetrating the plasma and may be important in explaining why the ELM frequency increases. The number and location of the structures observed can be well described using vacuum modeling. Differences in radial extent and poloidal width from vacuum modeling are likely to be due to a combination of transport effects and plasma screening.
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Affiliation(s)
- A Kirk
- EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
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37
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Affiliation(s)
- D.A. Hartmann
- York Plasma Institute, Department of Physics, University of York, Heslington, York, YO10 5DQ U.K
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38
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Schmitz O. Plasma Edge Transport with Stochastic Magnetic Field Structures. FUSION SCIENCE AND TECHNOLOGY 2012. [DOI: 10.13182/fst12-a13509] [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)
- Oliver Schmitz
- Forschungszentrum Juelich GmbH, Institute for Energy and Climate Research 4 Association EURATOM-FZ Juelich, 52428 Juelich, Germany
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