Parametric Decay Instability near the Lower Hybrid Frequency and RF Plasma Heating
| Project/Area Number |
63460220
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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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 |
IDEHARA Toshitaka FUKUI UNIV., FACULTY OF ENGINEERING, ASS. PROF., 工学部, 助教授 (80020197)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAGISHI Masaaki TOTTORI UNIV., FACULTY OF EDUCATION, ASS. PROF., 教育学部, 助教授 (20031924)
TATSUKAWA Toshiaki FUKUI UNIV., FACULTY OF ENGINEERING, ASS. PROF., 工学部, 助教授 (00020206)
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| Project Period (FY) |
1988 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥7,200,000 (Direct Cost: ¥7,200,000)
Fiscal Year 1989: ¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1988: ¥5,100,000 (Direct Cost: ¥5,100,000)
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| Keywords | Parametic decay instability / Lower hybrid wave / rf heating / Sideband wave / Slow waveguiding circuit / 低域混成周波数 / プラズマ加熱 / サイドバンド |
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| Research Abstract |
1. Propagation of a lower hybrid wave in a plasma and generation of a parametric decay instability
We can control a propagation of lower hybrid wave, by using a slow waveguiding circuit surrounding a plasma column and controlling the wave number k parallel to a magnetic field and the frequency of applied rf power. The conditions for parametric decay instability are studied in detail, as a function of applied rf power. Observed sideband wave and low frequency wave are identified as a lower hybrid wave and an ion cyclotron wave, from observations of their frequency and wavenumber spectrums.
2. Control of the instability and penetration of rf power into plasma center
We can increase the shreshold of rf power for generation of the instability, by increasing the width of frequency spectrum of applied rf power and keep the whole applied rf power. As the results, the rf power can penetrate into the plasma center, by suppressing the heating of plasma surface resulting from the instability.
3. Local heating and acceleration at the center of plasma
The lower hybrid wave can arrive at the plasma center,trap electrons and accelerate them. As the results, electrons have a beam component. On the other hand, just after the rf power is applied, beam-like ions appear, as a result of acceleration effect due to the spatial variation of electrostatic potential.
After the instability occurs, electrons are heated by the acceleration due to the sideband wave and its harmonics. The effect is observed by a probe measurement and a spectroscopic measurement.
These results have impotent meanings as model experiments for a current drive and plasma heating of tokamak plasmas.
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Report
(3 results)
Research Products
(14 results)
