| Project/Area Number |
07680498
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
プラズマ理工学
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| Research Institution | Iwate University |
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Principal Investigator |
SATO Teruyuki Dpt.of Electrical and Electronic Engineering, Iwate University, Professor, 工学部, 教授 (70023702)
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| Co-Investigator(Kenkyū-buntansha) |
SATO Koichi Graduate School of Engineering, Nagoya University, Professor, 大学院・工学研究科, 教授 (40023733)
WATANABE Masayuki Dpt.of Electr.and Electronic Engineering, Iwate University, Research Associate, 工学部, 助手 (30271844)
SHIMADA Tsutomu Dpt.of Electr.and Electronic Engineering, Iwate University, Associate Professor, 工学部, 助教授 (10005316)
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| Project Period (FY) |
1995 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1996: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1995: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Keywords | Alfven wave / RFP-plasma / Reversed Field Pinch Configuration / wave excitation / magneto-hydro-dynamic wave / propagation characteristic / large amplitude wave / toroidal eigenmode / 逆転磁場配位 / 位相速度 |
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| Research Abstract |
In the reversed field pinch (RFP) operation, production of the quiet RFP plasma is preceded by a magnetic turbulent state. The transition from the turbulent to the quiet state is known as a self-organization. If we excite Alfven waves in the transition phase, we would expect that Alfven waves may change the mode of magnetic fluctuations. Therefore we may control the start-up phase of RFP plasmas by Alfven wave excitation.
We have excited Alfven waves in the IFTES RFP device (major radius R=30cm, minor radius alpha=3.9cm). Electrodes of Alfven wave excitation consist of two small copper pieces that are mounted at gamma=3.5cm and are separated 120ﾟ in the toroidal direction. These electrodes are connected to capacitors through a gap-switch. Oscillating current flows between two electrodes along the magnetic lines of force.
First, waves are excited in the ultra-low q tokamak plasma, because the magnetic configuration of the tokamak mode is much simple to confirm the wave propagation in comparison with the RFP mode. We have confirmed that the excited wave propagates in the toroidal direction with the Alfven velocity.
In the second place, the wave is excited in the RFP plasma. The radial distribution of the phase velocity is uniform, the value of which corresponds to the Alfven velocity. The wave amplitude is almost constant in the radial direction. The amplitude is more than 10% of the static magnetic field strength, so that the propagated wave lies in a region of the large-amplitude oscillation.
We can conclude from these results that some rather macroscopic large amplitude oscillation is excited in the whole RFP plasma, similar to a toroidal Alfven eigenmode.
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