1995 Fiscal Year Final Research Report Summary
Conversion of Submillimeter Wave Gyrotrn Output into a high Quality Beam and its Application to Plasme Scattering Measurement
| Project/Area Number |
06680441
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
プラズマ理工学
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| Research Institution | FUKUI UNIVERSITY |
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Principal Investigator |
OGAWA Isamu Fukui University Cryogenic Laboratory Associate Professor, 工学部, 助教授 (90214014)
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| Co-Investigator(Kenkyū-buntansha) |
TATSUKAWA Toshiaki Fukui University Applied Physics Associate Professor, 工学部, 助教授 (00020206)
IDEHARA Toshitaka Fukui University Applied Physics Professor, 工学部, 教授 (80020197)
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| Project Period (FY) |
1994 – 1995
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| Keywords | Plasama scattering measurement / Submillimeter wave beam / Submillimeter wave power source / Gyrotron / Submillimeter wave gyrotron / Submillimeter wave probe beam / Quasi-optical transmission line |
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| Research Abstract |
Objectives : Production of high quality, intense submillimeter wave beam and its application to plasma scattering measurement with the aim of improving performance of the measurement (S/N ratio, spatial and wave number resolutions)
The results :
1. Development of a high frequency gyrotron as intense power source in submillimeter wave range
A high frequency gyrotron in the submillimeter wavelength range using 17 T superconducting magnet has been designed and constructed. Experimental results have demonstrated operation from 158 to 443 GHz at the fundamental and from 336 to 838 GHz at the second harmonic. A submillimeter wave gyrotron can also produce steady outputs in a long pulse (P=110 W,power fluctuation level<8%, f=354 GHz, tau-0.6s) by closely adjusting the operation parameters.
2. Development of quasi-optical transmission line for producing a high quality beam
A new transmission line is designed for converting gyrotron output into a high quality beam. This consists of a quasi-optical antenna, mirrors and polarizer. Analysis using the Huygens equation supports that this system can produce a high quality beam. There is no sidelobe of more than-30 dB.Most of the power (83%) of the image source is transferred to beam center.
3. Plasma scattering measurement using a submillimeter wave gyotron as a power source
In order to obseve low frequency density fluctuations in the CHS (Compact Helical System) plasma, a plasma scattering measurement using a submillimeter wave gyrotron as a power source is carried out in ICRF heated plasmas. The results correspond to those of reflectmetry with frequency of 39 GHz. The final goal is to apply a high quality, high intensity beam in the submillimeter wave range to scattering measurements with the aim of improving performance of the measurement (S/N ratio, spatial and wave number resolutions).
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