Grant-in-Aid for Developmental Scientific Research
|Allocation Type||Single-year Grants |
|Research Institution||Fukui University |
IDEHARA Toshitake Fukui University, Faculty of Engineering Professor, 工学部, 教授 (80020197)
KAWAHATA Kazuo National Institute for Fusion Science Associate Professor, 助教授 (60109353)
FUJITA Junji National Institute for Fusion Science Professor, 教授 (50023700)
OKAMOTO Tadashi Toshiba Corporation, Research and Development Center
OGAWA Isamu Fukui University, Faculty of Engineering Associate Professor, 工学部, 助教授 (90214014)
TATSUKAWA Toshiaki Fukui University, Faculty of Engineering Associate Professor, 工学部, 助教授 (00020206)
岡山 正 株式会社東芝
|Project Period (FY)
1989 – 1991
Completed(Fiscal Year 1991)
|Budget Amount *help
¥17,500,000 (Direct Cost : ¥17,500,000)
Fiscal Year 1991 : ¥2,300,000 (Direct Cost : ¥2,300,000)
Fiscal Year 1990 : ¥6,300,000 (Direct Cost : ¥6,300,000)
Fiscal Year 1989 : ¥8,900,000 (Direct Cost : ¥8,900,000)
|Keywords||Gyrotron / Submillimeter wave source / Scattering measurement / Quasi-optical antenna / Cyclotron harmonic operation / Superconducting magnet / プラズマ散乱計測 / サブミリ波散乱計測 / 負吸収現象 / メ-ザ-作用 / 周波数可変ジャイロトロン / SCマグネット|
A gyrotron is a high power source covering millimeter and submillimeter wavelength ranges. We are planning the development of high frequency, cyclotron harmonic gyrotrons and their application to scattering measurement of plasma.
1. Development of a gyrotron covering a submillimeter wavelength range
We have made up a 8-12 T superconducting magnet which is optimized for a gyrotron and designed an electron gun and a cylindrical cavity to construct the gyrotron tube. We have tested the gyrotrons made on the basis of the designs and obtained following results.
(1) A new harmonic gyrotron has produced a submillimeter wave, output power at the 2nd harmonic resonance. Its maximum frequency is 404 GHz (the corresponding wavelength is 0.75 mm) and its power is several kW. Gyrotron IVA of University of Sydney has achieved high frequency operations up to 516 GHz, which is the world record for a stable gyrotron. The work was done under collaboration with our group.
(2) Cyclotron harmonic operations up
to 3rd have been observed at 354 GHz (TE_<161> cavity mode), which are necessary for a high frequency gyrotron. Our gyro-peniotron has produced a high power (-3.3kW) at a high frequency (-140 GHz) under the 3rd harmonic resonance.
(3) We have successfully done a long pulse operation up to 600 msec under the second harmonic operation at 354 GHz (the corresponding wavelength is 0.85 mm). The operation is used for scattering measurement of plasma.
(4) Computer simulation results show the mode competition between the fundamental and the second harmonic operations. The results are confirmed by using our submillimeter wave gryotron. We have found the conditions for single mode operation at the second harmonic, which is necessary for high frequency gyrotron as a submillimeter wave source.
2. Application of a submillimeter wave gyrotron to scattering measurement of plasma
(1) We have developed elements for quasi-optical circuit, for example, quasi-optical antennae, using outputs of our gyrotrons. The elements are used in the scattering measurement system for plasmas.
(2) We have constructed the system using our gyrotron as a power source and applied it to the helical system (CHS) of National Institute of Fusion Science and succeeded to observe a spontaneously excited, low frequency drift wave. Less