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Funaba H, Yasuhara R, Uehara H, Yamada I, Sakamoto R, Osakabe M, Den Hartog DJ. Electron temperature and density measurement by Thomson scattering with a high repetition rate laser of 20 kHz on LHD. Sci Rep 2022; 12:15112. [PMID: 36068266 PMCID: PMC9448754 DOI: 10.1038/s41598-022-19328-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 08/29/2022] [Indexed: 11/30/2022] Open
Abstract
Thomson scattering measurements with a high-repetition-rate laser have commenced in the Large Helical Device. As an example of the fast phenomena captured by this diagnostic system, measurements at a 20 kHz repetition-rate in hydrogen pellet-injected plasmas are presented. Signal processing methods for this measurement have been developed and electron temperature profiles with almost 70 spatial points were evaluated at time intervals of 50 [Formula: see text]s. After Raman scattering calibration, electron density profiles were derived. Fast changes in the electron temperature and density profiles within 1 ms were observed.
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Affiliation(s)
- H Funaba
- National Institute for Fusion Science, National Institutes of Natural Sciences, Toki, Gifu, 509-5292, Japan.
| | - R Yasuhara
- National Institute for Fusion Science, National Institutes of Natural Sciences, Toki, Gifu, 509-5292, Japan.
| | - H Uehara
- National Institute for Fusion Science, National Institutes of Natural Sciences, Toki, Gifu, 509-5292, Japan
| | - I Yamada
- National Institute for Fusion Science, National Institutes of Natural Sciences, Toki, Gifu, 509-5292, Japan
| | - R Sakamoto
- National Institute for Fusion Science, National Institutes of Natural Sciences, Toki, Gifu, 509-5292, Japan
| | - M Osakabe
- National Institute for Fusion Science, National Institutes of Natural Sciences, Toki, Gifu, 509-5292, Japan
| | - D J Den Hartog
- Department of Physics, University of Wisconsin-Madison, Madison, WI, 53706-1390, USA
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Gangradey R, Mishra J, Mukherjee S, Panchal P, Nayak P, Agarwal J, Saxena YC. SPINS-IND: Pellet injector for fuelling of magnetically confined fusion systems. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:063503. [PMID: 28668001 DOI: 10.1063/1.4985639] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Using a Gifford-McMahon cycle cryocooler based refrigeration system, a single barrel hydrogen pellet injection (SPINS-IND) system is indigenously developed at Institute for Plasma Research, India. The injector is based on a pipe gun concept, where a pellet formed in situ in the gun barrel is accelerated to high speed using high pressure light propellant gas. The pellet size is decided by considering the Greenwald density limit and its speed is decided by considering a neutral gas shielding model based scaling law. The pellet shape is cylindrical of dimension (1.6 mm ℓ × 1.8 mm φ). For pellet ejection and acceleration, a fast opening valve of short opening duration is installed at the breech of the barrel. A three-stage differential pumping system is used to restrict the flow of the propellant gas into the plasma vacuum vessel. Diagnostic systems such as light gate and fast imaging camera (240 000 frames/s) are employed to measure the pellet speed and size, respectively. A trigger circuit and a programmable logic controller based integrated control system developed on LabVIEW enables to control the pellet injector remotely. Using helium as a propellant gas, the pellet speed is varied in the range 650 m/s-800 m/s. The reliability of pellet formation and ejection is found to be more than 95%. This paper describes the details of SPINS-IND and its test results.
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Affiliation(s)
- R Gangradey
- Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428, India
| | - J Mishra
- Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428, India
| | - S Mukherjee
- Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428, India
| | - P Panchal
- Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428, India
| | - P Nayak
- Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428, India
| | - J Agarwal
- Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428, India
| | - Y C Saxena
- Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428, India
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Miyazawa J, Masuzaki S, Sakamoto R, Peterson BJ, Tamura N, Goto M, Kobayashi M, Shoji M, Akiyama T, Yamada H. Density Limits for the Core and Edge Plasmas Related to the Local Temperatures in LHD. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst10-a10807] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- J. Miyazawa
- National Institute for Fusion Science, Toki, Gifu 509-5292, Japan
| | - S. Masuzaki
- National Institute for Fusion Science, Toki, Gifu 509-5292, Japan
| | - R. Sakamoto
- National Institute for Fusion Science, Toki, Gifu 509-5292, Japan
| | - B. J. Peterson
- National Institute for Fusion Science, Toki, Gifu 509-5292, Japan
| | - N. Tamura
- National Institute for Fusion Science, Toki, Gifu 509-5292, Japan
| | - M. Goto
- National Institute for Fusion Science, Toki, Gifu 509-5292, Japan
| | - M. Kobayashi
- National Institute for Fusion Science, Toki, Gifu 509-5292, Japan
| | - M. Shoji
- National Institute for Fusion Science, Toki, Gifu 509-5292, Japan
| | - T. Akiyama
- National Institute for Fusion Science, Toki, Gifu 509-5292, Japan
| | - H. Yamada
- National Institute for Fusion Science, Toki, Gifu 509-5292, Japan
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Ploeckl B, Day C, Lamalle P, Lang P, Rohde V, Viezzer E. The enhanced pellet centrifuge launcher at ASDEX Upgrade: Advanced operation and application as technology test facility for ITER and DEMO. FUSION ENGINEERING AND DESIGN 2015. [DOI: 10.1016/j.fusengdes.2015.01.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Lee HY, Hong SH, Hong J, Lee SH, Jang S, Jang J, Jeon T, Park JS, Choe W. Development of a particle injection system for impurity transport study in KSTAR. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:11D862. [PMID: 25430275 DOI: 10.1063/1.4886958] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A solid particle injection system is developed for KSTAR. The system has a compact size, compatibility with a strong magnetic field and high vacuum environment, and the capability to inject a small amount of solid particles with a narrow injection angle. The target flight-distance of 10 cm has been achieved with a particle loss rate of less than 10%. Solid impurity particles such as tungsten and carbon will be injected by this system at the midplane in KSTAR. The impurity transport feature will be studied with a soft X-ray array, a vacuum ultra-violet diagnostic, and Stand Alone Non-Corona code.
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Affiliation(s)
- H Y Lee
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea and Fusion Plasma Transport Research Center, Daejeon 305-701, Republic of Korea
| | - Suk-Ho Hong
- National Fusion Research Institute, Daejeon 305-806, Republic of Korea
| | - Joohwan Hong
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea and Fusion Plasma Transport Research Center, Daejeon 305-701, Republic of Korea
| | - Seung Hun Lee
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea and Fusion Plasma Transport Research Center, Daejeon 305-701, Republic of Korea
| | - Siwon Jang
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea and Fusion Plasma Transport Research Center, Daejeon 305-701, Republic of Korea
| | - Juhyeok Jang
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea and Fusion Plasma Transport Research Center, Daejeon 305-701, Republic of Korea
| | - Taemin Jeon
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea and Fusion Plasma Transport Research Center, Daejeon 305-701, Republic of Korea
| | - Jae Sun Park
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea and Fusion Plasma Transport Research Center, Daejeon 305-701, Republic of Korea
| | - Wonho Choe
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea and Fusion Plasma Transport Research Center, Daejeon 305-701, Republic of Korea
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Sakamoto R, Motojima G, Hayashi H, Inoue T, Ito Y, Ogawa H, Takami S, Yokota M, Yamada H. Twenty barrel in situ pipe gun type solid hydrogen pellet injector for the Large Helical Device. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2013; 84:083504. [PMID: 24007062 DOI: 10.1063/1.4816823] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A 20 barrel solid hydrogen pellet injector, which is able to inject 20 cylindrical pellets with a diameter and length of between 3.0 and 3.8 mm at the velocity of 1200 m/s, has been developed for the purpose of direct core fueling in LHD (Large Helical Device). The in situ pipe gun concept with the use of compact cryo-coolers enables stable operation as a fundamental facility in plasma experiments. The combination of the two types of pellet injection timing control modes, i.e., pre-programing mode and real-time control mode, allows the build-up and sustainment of high density plasma around the density limit. The pellet injector has demonstrated stable operation characteristics during the past three years of LHD experiments.
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Affiliation(s)
- Ryuichi Sakamoto
- National Institute for Fusion Science, Toki, Gifu 509-5292, Japan
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Motojima G, Sakamoto R, Goto M, Matsuyama A, Mishra JS, Yamada H. Imaging spectroscopy diagnosis of internal electron temperature and density distributions of plasma cloud surrounding hydrogen pellet in the Large Helical Device. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:093506. [PMID: 23020375 DOI: 10.1063/1.4751866] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
To investigate the behavior of hydrogen pellet ablation, a novel method of high-speed imaging spectroscopy has been used in the Large Helical Device (LHD) for identifying the internal distribution of the electron density and temperature of the plasma cloud surrounding the pellet. This spectroscopic system consists of a five-branch fiberscope and a fast camera, with each objective lens having a different narrow-band optical filter for the hydrogen Balmer lines and the background continuum radiation. The electron density and temperature in the plasma cloud are obtained, with a spatial resolution of about 6 mm and a temporal resolution of 5 × 10(-5) s, from the intensity ratio measured through these filters. To verify the imaging, the average electron density and temperature also have been measured from the total emission by using a photodiode, showing that both density and temperature increase with time during the pellet ablation. The electron density distribution ranging from 10(22) to 10(24) m(-3) and the temperature distribution around 1 eV have been observed via imaging. The electron density and temperature of a 0.1 m plasma cloud are distributed along the magnetic field lines and a significant electron pressure forms in the plasma cloud for typical experimental conditions of the LHD.
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Affiliation(s)
- G Motojima
- National Institute for Fusion Science, 322-6, Oroshi-cho, Toki-City, Gifu 509-5292, Japan.
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Hoshino M, Sakamoto R, Yamada H, Kumazawa R, Watari T. Performance of fueling pellet injectors for the large helical device. FUSION ENGINEERING AND DESIGN 2006. [DOI: 10.1016/j.fusengdes.2006.07.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Combs S, Baylor L, Fisher P, Foust C, Gouge M, Pavarin D, Sakamoto R, Twynam P, Watson M, Yamada H. ORNL mock-up tests of inside launch pellet injection on JET and LHD. FUSION ENGINEERING AND DESIGN 2001. [DOI: 10.1016/s0920-3796(01)00379-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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