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227 results on '"TATEMATSU, Yoshinori"'

11. Multifrequency Electron Spin Resonance Using a High-Power Light Source Compact Gyrotron and Force-Detection System

Author

Ishikawa, Yuya, primary, Takahashi, Hideyuki, additional, Okutani, Akira, additional, Hayashi, Kanata, additional, Sano, Tomonori, additional, Hirozawa, Kouhei, additional, Ito, Takero, additional, Masuda, Shota, additional, Ohmichi, Eiji, additional, Ohta, Hitoshi, additional, Tatematsu, Yoshinori, additional, Asano, Takayuki, additional, Kikuchi, Hikomitsu, additional, Fujii, Yutaka, additional, and Mitsudo, Seitaro, additional

Published
2023
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17. Developments for collective Thomson scattering equipment with a sub-THz gyrotron in LHD

Author

Saito Teruo, Tatematsu Yoshinori, Yamaguchi Yuusuke, Fukunari Masafumi, Hirobe Takumi, Shinbayashi Ryushi, Tanaka Shunsuke, Ohkubo Kunizo, Kubo Shin, Shimozuma Takashi, Tanaka Kenji, and Nishiura Masaki

Subjects
Physics, QC1-999
Abstract

Plan of collective Thomson scattering (CTS) experiment for the Large Helical Device (LHD) in NIFS with a 303 GHz gyrotron is under way. Use of a sub-THz gyrotron expands the CTS-applicable region of plasma parameters. In LHD, sub-THz CTS can be applied to the high density operation region, plasmas with impurity hole, etc. Moreover, sub-THz CTS is expected to be free from ECE noise. Its “collective” use with 77 GHz and 154 GHz CTS will compose a powerful diagnostic system. A high power sub-THz gyrotron with a frequency of 303 GHz has been developed. Its maximum power is 320 kW. It oscillates in pulse mode and the maximum pulse width is around 100 μs, which is sufficient for use in CTS experiments. A whispering gallery mode TE22,2 was adopted for this gyrotron to avoid mode competition. Careful frequency measurement has proved purely single mode oscillation of the TE22,2 mode including turn-on and turn-off phases of the oscillation pulse. This is consistent with mode competition calculations taking account of a finite voltage rise time. A low loss transmission line is necessary for CTS. We have two possibilities. One is a new line with 1.25 inch corrugated waveguides that are optimized for the 300 GHz band. Transmission test with the 303 GHz gyrotron has been carried out and a sufficiently low loss coefficient has been confirmed. The other is to use an existing line with 3.5 inch corrugated waveguides for lower frequencies such as 77 GHz and 154 GHz. Transmission test has been carried out with the 303 GHz gyrotron and a sufficiently low loss coefficient has been confirmed also for 3.5 inch corrugated waveguides. An existing line with 3.5 inch corrugated waveguides will be used in the initial phase of 303 GHz CTS experiment.

Published
2019
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18. Optimization of Megawatt 77-GHz Gyrotron Operation for Collective Thomson Scattering in LHD

Author

OGASAWARA, Shinya, KUBO, Shin, NISHIURA, Masaki, TATEMATSU, Yoshinori, SAITO, Teruo, TANAKA, Kenji, SHIMOZUMA, Takashi, YOSHIMURA, Yasuo, IGAMI, Hiroe, TAKAHASHI, Hiromi, ITO, Satoshi, MAKINO, Ryohei, KOBAYASHI, Sakuji, MIZUNO, Yoshinori, OKADA, Kohta, MINAMI, Ryutaro, KARIYA, Tsuyoshi, IMAI, Tsuyoshi, OGASAWARA, Shinya, KUBO, Shin, NISHIURA, Masaki, TATEMATSU, Yoshinori, SAITO, Teruo, TANAKA, Kenji, SHIMOZUMA, Takashi, YOSHIMURA, Yasuo, IGAMI, Hiroe, TAKAHASHI, Hiromi, ITO, Satoshi, MAKINO, Ryohei, KOBAYASHI, Sakuji, MIZUNO, Yoshinori, OKADA, Kohta, MINAMI, Ryutaro, KARIYA, Tsuyoshi, and IMAI, Tsuyoshi

Abstract

To establish a method for suppressing the spurious radiation that interferes with collective Thomson scattering measurements with less degradation of the main mode output power, the frequency evolution, and the output power of the megawatt 77-GHz gyrotron were measured during operation under optimized parameters. According to a mode competition calculation, the main mode output power may be increased by setting a lower gyrotron anode voltage at a higher magnetic field strength in the gyrotron resonator. Although the output power increased from 300 kW to 530 kW without any spurious radiation when the optimized operational parameters were used, the output power was about 50% of that at a lower magnetic field strength, and thus the output pulse width was limited to 60 ms. When an approach using the optimized operational parameters and a PIN switch was applied, the output power increased to 800 kW without any harmful spurious radiation effect and the pulse width was expanded to 2 s., source:https://doi.org/10.1585/pfr.8.2402069

Published
2022

24. Review of subterahertz and terahertz gyrodevices at IAP RAS and FIR FU

Author

Bratman, Vladimir, Glyavin, Mikhail, Idehara, Toshitaka, Kalynov, Yuri, Luchinin, Alexey, Manuilov, Vladimir, Mitsudo, Seitaro, Ogawa, Isamu, Saito, Teruo, Tatematsu, Yoshinori, and Zapevalov, Vladimir

Subjects
Plasma physics -- Analysis, Internet service providers -- Methods, Gyroscopes -- Magnetic properties, Internet service provider, Business, Chemistry, Electronics, Electronics and electrical industries
Abstract

The maximal frequency of radiation higher than 1 THz has been recently obtained in pulse gyrotrons both at IAP (Nizhny Novgorod, Russia) and FIR (Fukui, Japan). CW generation at a 2.2-kW power level is radiated from a 300-GHz gyrotron and used for technological applications. New gyrotrons demonstrate single-mode operation at the second cyclotron harmonic with a frequency of 395 GHz in the CW regime with a power of 100 W and at the third harmonic with frequencies of 371-414 GHz in 10-[micro]s pulses with power of 10-20 kW. Methods of selective excitation of higher cyclotron harmonics, frequency multiplication, and smooth frequency tuning in terahertz gyrotrons are also discussed in the review. Index Terms--Frequency tunability, gyrotron, harmonics, large-orbit gyrotron (LOG), powerful generation, pulse magnetic field, subterahertz, terahertz.

Published
2009

25. Collective Thomson scattering with 77, 154, and 300 GHz sources in LHD

Author

Nishiura, M., TANAKA, Kenji, KUBO, Shin, Saito, T., Kenmochi, Naoki, NUGA, Hideo, SEKI, Ryosuke, SHIMOZUMA, Takashi, YOSHIMURA, Yasuo, IGAMI, Hiroe, TAKAHASHI, Hiromi, Tsujimura, Ii Toru, YANAI, R., TATEMATSU, Yoshinori, Nishiura, M., TANAKA, Kenji, KUBO, Shin, Saito, T., Kenmochi, Naoki, NUGA, Hideo, SEKI, Ryosuke, SHIMOZUMA, Takashi, YOSHIMURA, Yasuo, IGAMI, Hiroe, TAKAHASHI, Hiromi, Tsujimura, Ii Toru, YANAI, R., and TATEMATSU, Yoshinori

Abstract

Collective Thomson scattering (CTS) is one of attractive diagnostics for measuring locally and directly the fuel temperature and the velocity distribution of fast ions in fusion plasmas. A mega-watt class source of millimeter or sub-millimeter waves is required to detect a weak scattered radiation superimposed on background radiation owing to electron cyclotron emissions (ECEs) from plasmas. Based on electron cyclotron resonance heating (ECRH) system with the frequencies of 77 GHz and 154 GHz in the Large Helical Device (LHD), the CTS diagnostic system has been developed to measure bulk ion temperatures from a few keV to ∼10 keV and fast ions originated from 180 keV-neutral beam injection in the LHD. The measured CTS spectra and their time evolutions are analyzed with the electrostatic scattering theory. The bulk ion temperatures obtained from CTS spectra increase with the neutral beam injections and decrease with the heating terminated. The velocity map of simulated fast ions explains that the bumps on tail of measured CTS spectra are caused by the co- and counter- fast ions. A new prescription for anisotropic velocity distribution function is proposed. As for 154 GHz bands, the CTS spectrum broadenings for D and H plasmas are distinguished reasonably at the same temperature, and its ion temperatures are comparable to those of the charge exchange recombination spectroscopy. As reactor-relevant diagnostics, a 300 GHz gyrotron and a corresponding receiver system have been implemented in LHD to access high density plasmas with low background ECEs. The recent progress for CTS diagnostics and their spectrum analysis with the probe frequencies of 77 GHz, 154 GHz, and 300 GHz in the LHD experiments is described., source:M. Nishiura et al 2020 JINST 15 C01002, source:https://doi.org/10.1088/1748-0221/15/01/C01002, identifier:0000-0003-2410-7550

Published
2021

28. Influence of the Aftercavity Interaction on the Output Power of a Gyrotron Operating at a High-Order Axial Mode

Author

Khutoryan, Eduard, primary, Kuleshov, Alexei, additional, Fedotov, Alexey, additional, Sabchevski, Svilen, additional, Bandurkin, Ilya, additional, Manuilov, Vladimir, additional, Zotova, Irina, additional, Fokin, Andrey, additional, Kishko, Sergey, additional, Ponomarenko, Sergey, additional, Ishikawa, Yuya, additional, Fukunari, Masafumi, additional, Saito, Teruo, additional, Tatematsu, Yoshinori, additional, Mitsudo, Seitaro, additional, Idehara, Toshitaka, additional, and Glyavin, Mikhail, additional

Published
2021
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29. Production of high-density plasmas with high harmonic fast waves in the GAMMA 10 tandem mirror

Author

Ichimura, Makoto, Cho, Teruji, Higaki, Hiroyuki, Hirata, Mafumi, Hojo, Hitoshi, Horinouchi, Kentarou, Ishii, Kameo, Islam, M.K., Itakura, Akiyosi, Kakimoto, Shingo, Katanuma, Isao, Kohagura, Junko, Nakashima, Yousuke, Saito, Teruo, Tatematsu, Yoshinori, Yamaguchi, Yuusuke, Yatsu, Kiyoshi, and Yoshikawa, Masayuki

Subjects
Plasma (Ionized gases) -- Research, Business, Chemistry, Electronics, Electronics and electrical industries
Abstract

By using high harmonic fast waves (HHFW), the density clamping due to the formation of axial eigenmodes becomes weak in the GAMMA 10 tandem mirror. The excitation of HHFW is confirmed and the transition from the mode with a large axial wave number to the mode with a small wave number is detected. The production of high-energy ions as well as high-density plasmas is observed and the initial ion-temperature dependence of the higher harmonic damping is discussed. Index Terms--Plasma heating, plasma production.

Published
2004

40. Low-Voltage Operation of the Double-Beam Gyrotron at 400 GHz

Author

Kuleshov, Alexei, primary, Ishikawa, Yuya, additional, Tatematsu, Yoshinori, additional, Mitsudo, Seitaro, additional, Idehara, Toshitaka, additional, Khutoryan, Eduard, additional, Kishko, Sergey, additional, Ponomarenko, Sergey, additional, Glyavin, Mikhail, additional, Bandurkin, Ilya, additional, Manuilov, Vladimir, additional, Fedotov, Alexey, additional, and Saito, Teruo, additional

Published
2020
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41. Evaluation of Rectenna using 303 GHz Gyrotron

Author

Takagi, Kengo, Minakawa, Shunsuke, Mizojiri, Sei, Shimamura, Kohei, Yokota, Shigeru, Saito, Teruo, Tatematsu, Yoshinori, Yamaguchi, Hiroshi, and Fukunari, Masafumi

Abstract

第37回宇宙エネルギーシンポジウム (2018年3月5日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)), 相模原市, 神奈川県, 37th ISAS Space Energy Symposium (March 5, 2018. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS)), Sagamihara, Kanagawa Japan, 資料番号: SA6000125008, レポート番号: 8

Published
2018

50. マイクロ波ロケットにおける亜臨界ミリ波放電構造の露光画像計測

Author

Fukunari, Masafumi, Yokoyama, Tetsuo, Hirobe, Takumi, Shinbayashi, Ryuji, Tanaka, Shunsuke, Yamaguchi, Yusuke, Tatematsu, Yoshinori, and Saito, Teruo

Abstract

平成29年度宇宙輸送シンポジウム（2018年1月18日-19日. 宇宙航空研究開発機構宇宙科学研究所（JAXA)(ISAS)）, 相模原市, 神奈川県, Space Transportation Symposium FY2017 (January 18-19, 2018. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan, 資料番号: SA6000210113, レポート番号: STEP-2017-056

Published
2018

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