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2004 Fiscal Year Final Research Report Summary

Microwave Imaging Diagnostics in LHD

Research Project

Project/Area Number 14208055
Research Category

Grant-in-Aid for Scientific Research (A)

Allocation TypeSingle-year Grants
Section一般
Research Field Nuclear fusion studies
Research InstitutionNational Institute for Fusion Science

Principal Investigator

NAGAYAMA Yoshio  National Institute for Fusion Science, Department of Large Helical Device Project, Professor, 大型ヘリカル研究部, 教授 (10126138)

Co-Investigator(Kenkyū-buntansha) MORISHITA Kazuo (川端 一男)  National Institute for Fusion Science, Department of Large Helical Device Project, Professor, 大型ヘリカル研究部, 教授 (60109353)
MASE Atsushi  Kyushu University, KASTEC, Professor, 産学連携センター, 教授 (00023325)
INAGAKI Shigeru  National Institute for Fusion Science, Department of Large Helical Device Project, Research Associate, 大型ヘリカル研究部, 助手 (60300729)
TOKUZAWA Tokihiko  National Institute for Fusion Science, Department of Large Helical Device Project, Research Associate, 大型ヘリカル研究部, 助手 (90311208)
TANAKA Kenji  National Institute for Fusion Science, Department of Large Helical Device Project, Associate Professor, 大型ヘリカル研究部, 助教授 (50260047)
Project Period (FY) 2002 – 2004
KeywordsLHD / Imaging / Reflectometrv / Micro-instability / microwave / MIR / plasma / turbulence
Research Abstract

A new diagnostic tool for the plasma density fluctuations measurements was developed at National Institute for Fusion Science. For the first time the Microwave, Imaging Reflectometer was deployed for plasma measurements at heliotron (stellarator) class of the thermonuclear fusion devices. Based on main LHD plasma parameters (magnetic field strength and electron plasma density) MIR system operates at 66,69GHz with extra-ordinary orientation of the launching microwave radiation. To deliver very broad Gaussian beam and to pick-up reflected radiation from precisely localized spatial regions inside plasma a very sophisticated Quasi-optical system with combination of high-sensitive detectors was installed. To extend the ability of the MIR system to operate with Electron Cyclotron Emission Imaging diagnostic special quasi-optical splitter (dichroic plate) was used. Both the MIR and ECEI techniques take advantage of large aperture optics to form an image of the reflecting/emitting layer onto a … More n array of detectors located at the image plane, enabling localized sampling of small plasma areas. To obtain the information on plasma fluctuations in poloidal, toroidal and radial directions a multiple antenna system was used.
Low frequency plasma density oscillation (2-3 kHz) was observed during NBI plasma heating for regime with low plasma electron density. Some partial correlation (with correlation time 2.5 ms) was shown for poloidally separated detection channels. However, there was no clear evidence of the toroidal correlation in the reflected signals. From those data the estimated value Vθ=44 m/s of poloidal rotation velocity was obtained. During the experiments it was found that due to the very complicated 3-D shape of the plasma in the LHD device the issue of reflected beams focusing becomes of great importance. To improve the quasi-optical antenna system new elliptical antenna with variable steering angle is proposed. This will be giving a better flexibility to optimize the beam-line of the reflected radiation in order to achieve the maximum power of the reflected microwaves. Less

  • Research Products

    (12 results)

All 2005 2004 2003

All Journal Article (12 results)

  • [Journal Article] マイクロ波イメージング2005

    • Author(s)
      長山 好夫, 間瀬 淳
    • Journal Title

      プラズマ・核融合学会誌 81(印刷中)

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Experiment of Magnetic Island Formation in Large Helical Device2005

    • Author(s)
      Y.Nagayama, et al.
    • Journal Title

      Nuclear Fusion (印刷中)

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Microwave Imaging2005

    • Author(s)
      Y.Nagayama, A.Mase
    • Journal Title

      Journal of Plasma and Fusion Research Vol.81. No.5(printing)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Experiment of Magnetic Island Formation in Large Helical Device2005

    • Author(s)
      Y.Nagayama, et al.
    • Journal Title

      Nuclear Fusion. (submitted to)(in printing)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Electron Cyclotron Emission Diagnostics for Helical Plasma in the Large helical Device2004

    • Author(s)
      Y.Nagayama, et al.
    • Journal Title

      IEEE Transactions on Plasma Science 32

      Pages: 1716-1720

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Observation of Reduced Heat Transport inside the Magnetic Island 0 Point in the Large Helical Device2004

    • Author(s)
      S.Inagaki, et al.
    • Journal Title

      Physical Review Letters 92

      Pages: 055002

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Electron Cyclotron Emission Diagnostics for Helical Plasma in the Large Helical Device2004

    • Author(s)
      Y.Nagayama, et al.
    • Journal Title

      IEEE Transactions on Plasma Science Vol.32 No.4

      Pages: 1716-1720

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Observation of Reduced Heat Transport inside the Magnetic Island O Point in the Large Helical Device2004

    • Author(s)
      S.Inagaki, et al.
    • Journal Title

      Physical Review Letters Vol.92

      Pages: p.055002

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Electron Cyclotron Emission Diagnostics in Large Helical Device2003

    • Author(s)
      Y.Nagayama, et al.
    • Journal Title

      Journal of Plasma and Fusion Research 79

      Pages: 601-607

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Sawtooth Oscillation in Helical Plasma with Beam Driven Current in Large Helical Device2003

    • Author(s)
      Y.Nagayama, et al.
    • Journal Title

      Physical Review Letters 90

      Pages: 205001

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Electron Cyclotron Emission Diagnostics in Large Helical Device2003

    • Author(s)
      Y.Nagayama, et al.
    • Journal Title

      Journal of Plasma and Fusion Research Vol.79 No.6

      Pages: 601-607

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Sawtooth Oscillation in Helical Plasma with Beam Driven Current in Large Helical Device2003

    • Author(s)
      Y.Nagayama, et al.
    • Journal Title

      Physical Review Letters Vol.90 No.20

      Pages: p.205001

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 2006-07-11  

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