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Kobayashi M, Ohdachi S, Xu Y, Li W, Shimizu A, Cheng J. Gas puff imaging system for edge plasma fluctuation measurements in large helical device. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:093513. [PMID: 36182456 DOI: 10.1063/5.0100301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 07/28/2022] [Indexed: 06/16/2023]
Abstract
A gas puff imaging system has been developed to measure edge fluctuations in large helical device. The optical system splits the image of the plasma into four wavelengths, Hα/Dα (656 nm), HeI (1s2p-1s3d; 587.6; 1s2p-1s3d, 667.8; and 1s2p-1s3s, 706.5 nm), enabling simultaneous measurement of the spatial distribution of line ratios of He I. The image of the plasma is amplified with an image intensifier and recorded with a fast-framing camera. The measurement area has a diameter of 20 cm just outside of the last closed flux surface. The spatial resolution of the optical system is about 3 mm, and the frame rate is 100 kHz for acquisition of the four wavelength images. Signal-to-noise ratio is evaluated for the system, and further improvement is discussed. Clear images are obtained for all wavelengths and a slightly different pattern is recognized, depending on the wavelength. A singular value decomposition analysis can decompose the image clearly to one perpendicular and parallel to the magnetic field lines.
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Affiliation(s)
- M Kobayashi
- National Institute for Fusion Science, National Institutes of Natural Sciences, Toki, Gifu 509-5292, Japan
| | - S Ohdachi
- National Institute for Fusion Science, National Institutes of Natural Sciences, Toki, Gifu 509-5292, Japan
| | - Y Xu
- Institute of Fusion Science, School of Physical Science and Technology, Southwest Jiaotong University, Chengdu, Sichuan 610031, China
| | - W Li
- Institute of Fusion Science, School of Physical Science and Technology, Southwest Jiaotong University, Chengdu, Sichuan 610031, China
| | - A Shimizu
- National Institute for Fusion Science, National Institutes of Natural Sciences, Toki, Gifu 509-5292, Japan
| | - J Cheng
- Institute of Fusion Science, School of Physical Science and Technology, Southwest Jiaotong University, Chengdu, Sichuan 610031, China
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Hayashi Y, Kobayashi M, Mukai K, Masuzaki S, Murase T. Divertor heat load distribution measurements with infrared thermography in the LHD helical divertor. FUSION ENGINEERING AND DESIGN 2021. [DOI: 10.1016/j.fusengdes.2021.112235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Perseo V, Gradic D, König R, Ford OP, Killer C, Grulke O, Ennis DA. Coherence imaging spectroscopy at Wendelstein 7-X for impurity flow measurements. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:013501. [PMID: 32012578 DOI: 10.1063/1.5126098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 12/10/2019] [Indexed: 06/10/2023]
Abstract
In the last decade, Coherence Imaging Spectroscopy (CIS) has shown distinctive results in measuring ion flow velocities in the edge of magnetically confined plasma devices. Its 2D spatially resolved measurement capabilities and its high optical throughput are ideal for investigating the impurity behavior in the complex 3D magnetic island topology edge of Wendelstein 7-X (W7-X). However, a highly precise and stable calibration method is required for a reliable diagnostic operation. A new level of precision and stability has been achieved for the two CIS systems installed at W7-X with the use of a new calibration source, a continuous tunable laser commercially available only since 2015. A specific prototype model was successfully adapted to the challenging requirements of W7-X, granting high accuracy (±0.01 pm) and flexibility (spectral range: 450-650 nm) in the wavelength calibration required for measuring low-Z impurity ion flow velocities. These features opened up new investigation possibilities on temperature stability and wavelength response of the CIS components, allowing to fully characterize and validate the W7-X systems. The CIS diagnostic was operational throughout the last W7-X experimental campaign. Measured velocities on the order of ∼20-30 km/s were observed, corroborated by comparisons with measurements with Mach probes.
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Affiliation(s)
- Valeria Perseo
- Max-Planck-Institut für Plasmaphysik, 17491 Greifswald, Germany
| | - Dorothea Gradic
- Max-Planck-Institut für Plasmaphysik, 17491 Greifswald, Germany
| | - Ralf König
- Max-Planck-Institut für Plasmaphysik, 17491 Greifswald, Germany
| | - Oliver P Ford
- Max-Planck-Institut für Plasmaphysik, 17491 Greifswald, Germany
| | - Carsten Killer
- Max-Planck-Institut für Plasmaphysik, 17491 Greifswald, Germany
| | - Olaf Grulke
- Max-Planck-Institut für Plasmaphysik, 17491 Greifswald, Germany
| | - David A Ennis
- Department of Physics, Auburn University, Auburn, Alabama 36849, USA
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Morisaki T, Masuzaki S, Sakamoto R, Kobayashi M, Ohyabu N, Yamada H, Komori A. Local Island Divertor Experiment. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst10-a10810] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- T. Morisaki
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - S. Masuzaki
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - R. Sakamoto
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - M. Kobayashi
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - N. Ohyabu
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - H. Yamada
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - A. Komori
- National Institute for Fusion Science, Toki 509-5292, Japan
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Yamada H, Kawahata K, Mutoh T, Ohyabu N, Takeiri Y, Imagawa S, Ida K, Mito T, Nagayama Y, Shimozuma T, Watanabe KY, Kobayashi M, Kumazawa R, Masuzaki S, Morisaki T, Miyazawa J, Nagaoka K, Narushima Y, Sakakibara S, Sakamoto R, Toi K, Yokoyama M, Kaneko O, Komori A, Motojima O. Progress in the Integrated Development of the Helical System. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst10-a10789] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- H. Yamada
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - K. Kawahata
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - T. Mutoh
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - N. Ohyabu
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - Y. Takeiri
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - S. Imagawa
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - K. Ida
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - T. Mito
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - Y. Nagayama
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - T. Shimozuma
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - K. Y. Watanabe
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - M. Kobayashi
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - R. Kumazawa
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - S. Masuzaki
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - T. Morisaki
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - J. Miyazawa
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - K. Nagaoka
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - Y. Narushima
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - S. Sakakibara
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - R. Sakamoto
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - K. Toi
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - M. Yokoyama
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - O. Kaneko
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - A. Komori
- National Institute for Fusion Science, Toki 509-5292, Japan
| | - O. Motojima
- National Institute for Fusion Science, Toki 509-5292, Japan
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