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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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Lee MW, Kang J, Logan NC, Choi MJ, Jung L, Kim J, Choi MG, Kim MH, Grierson BA, Smith SP, Meneghini O, Romanelli M, Sung C. A New Integrated Analysis Suite for Fast-Ion Study in KSTAR. FUSION SCIENCE AND TECHNOLOGY 2022. [DOI: 10.1080/15361055.2022.2126292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- M. W. Lee
- Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Korea
| | - J. Kang
- Korea Institute of Fusion Energy, 169-148 Gwahangno, Yuseong-gu, Daejeon 34113 Korea
| | - N. C. Logan
- Lawrence Livermore National Laboratory, Livermore, California 94551
| | - M. J. Choi
- Korea Institute of Fusion Energy, 169-148 Gwahangno, Yuseong-gu, Daejeon 34113 Korea
| | - L. Jung
- Korea Institute of Fusion Energy, 169-148 Gwahangno, Yuseong-gu, Daejeon 34113 Korea
| | - J. Kim
- Korea Institute of Fusion Energy, 169-148 Gwahangno, Yuseong-gu, Daejeon 34113 Korea
| | - M. G. Choi
- Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Korea
| | - M. H. Kim
- Korea Institute of Fusion Energy, 169-148 Gwahangno, Yuseong-gu, Daejeon 34113 Korea
| | | | - S. P. Smith
- General Atomics, San Diego, California 92121
| | | | - M. Romanelli
- UKAEA, Culham Science Centre, Abingdon OX143DB, United Kingdom
| | - C. Sung
- Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Korea
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Development of a two color interferometer on a field-reversed configuration device. FUSION ENGINEERING AND DESIGN 2022. [DOI: 10.1016/j.fusengdes.2022.113201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Juhn JW, Lee KC, Lee TG, Wi HM, Kim YS, Hahn SH, Nam YU. Multi-chord IR-visible two-color interferometer on KSTAR. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:043559. [PMID: 34243393 DOI: 10.1063/5.0043811] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 03/29/2021] [Indexed: 06/13/2023]
Abstract
Major parts of an IR-visible two-color interferometer (TCI) on KSTAR have been upgraded for the multi-chord operation: (1) a diode-pumped-solid-state (DPSS) laser (660 nm) replacing the former HeNe laser (633 nm), (2) vacuum-compatible vibration isolator with titanium retro-reflectors, and (3) full digital phase comparator for multi-chord real-time density signals. The commercial compact DPSS laser suits the multiple chord configuration with its strong beam power (500 mW) and long coherent length (>100 m). Ti retro-reflectors are mounted on vacuum-compatible vibration isolators. The isolators are essential for the visible beams to avoid any fringe skips due to their short wavelength, considering the speed of the mechanical vibration (up to hundreds of μm). Field-programmable-gate-array (FPGA) modules count the entire fringes fast enough with a signal output rate up to 1.25 MHz, solving the fringe skip issues. The FPGA module enables the full digital processing of the phase comparator with a CORDIC algorithm after the sampling rate of 160 MS/s for the 40 MHz intermediate frequency of each beam. The full digital signals are transferred to the main plasma control system in real-time. Stable single-input-single-output operation of the KSTAR density control was demonstrated with the TCI. The real-time density profile control is also promising in the near future, with multiple actuators such as pellets and gas puffings.
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Affiliation(s)
- June-Woo Juhn
- Korea Institute of Fusion Energy, Daejeon 34133, Republic of Korea
| | - K C Lee
- Korea Institute of Fusion Energy, Daejeon 34133, Republic of Korea
| | - T G Lee
- Korea Institute of Fusion Energy, Daejeon 34133, Republic of Korea
| | - H M Wi
- Korea Institute of Fusion Energy, Daejeon 34133, Republic of Korea
| | - Y S Kim
- Korea Institute of Fusion Energy, Daejeon 34133, Republic of Korea
| | - S H Hahn
- Korea Institute of Fusion Energy, Daejeon 34133, Republic of Korea
| | - Y U Nam
- Korea Institute of Fusion Energy, Daejeon 34133, Republic of Korea
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Lee DG, Lee KC, Juhn JW, Lee JS, Ghim YC. The new single crystal dispersion interferometer installed on KSTAR and its first measurement. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:033536. [PMID: 33820011 DOI: 10.1063/5.0043629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 03/03/2021] [Indexed: 06/12/2023]
Abstract
Dispersion interferometers have been used to measure line integrated electron densities from many fusion devices. To optically suppress noise due to mechanical vibrations, a conventional dispersion interferometer typically uses two nonlinear crystals located before and after the plasma along the laser beam path. Due to the long beam path, it can be difficult to overlap the fundamental and second harmonic laser beams for a heterodyne dispersion interferometer and to focus the beams on the second nonlinear crystal located after the plasma, especially when the aperture of the nonlinear crystal is small, i.e., of the order of mm. To overcome such difficulties, a new concept of a heterodyne dispersion interferometer, a single crystal dispersion interferometer (SCDI), is developed and installed on KSTAR with the laser wavelength of 1064 nm. The concept and the optical setup of the KSTAR SCDI are discussed, as well as its first measurement during a shattered pellet injection that produces abrupt and large changes in the electron density. To demonstrate feasibility, the KSTAR SCDI measurements are also compared with those from the existing two-color interferometer.
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Affiliation(s)
- Dong-Geun Lee
- Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - K C Lee
- Korea Institute of Fusion Energy, Daejeon 34133, Republic of Korea
| | - J-W Juhn
- Korea Institute of Fusion Energy, Daejeon 34133, Republic of Korea
| | - Jae-Seok Lee
- Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Y-C Ghim
- Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
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EPICS data acquisition system for FPGA-based plasma electron density measurement on KSTAR. FUSION ENGINEERING AND DESIGN 2018. [DOI: 10.1016/j.fusengdes.2018.02.037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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