核融合研究

有限長イオンビーム・プラズマ系における不安定低周波

中村定男, 湯山哲守, 久保煕

1981 年 45 巻 3 号 p. 241-253
発行日: 1981年
公開日: 2011/03/04

DOIhttps://doi.org/10.1585/jspf1958.45.241

ジャーナルフリー

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One dimensional fluid equations are examined together with Poisson's equation for an ion beam plasma system by taking the boundary condition into account, as was done by Pierce for an electron beam. An ion acoustic wave and a slow wave of the beam under such a condition become unstable even if they are stable in an unbounded case. The wave split into many unstable new modes for given parameters of the system. Their frequencies as well as the growth rates depend largely on the length L of the system, the drift velocity V_o of the ion beam and the electron thermal velocity. The frequencies decrease monotonously with increasing the value of ^ωpi L/V_o. Meanwhile, the growth rates appear suddenly at certain values of ^ωpiL/V_o, and they attain to their maximum values at respective different ones and then they decrease gradualy. Each maximum growth rate is greater than the other growth rates for the same value of ^ωpiL/V_o. Theoretical results are compared with the experimental ones, which gives qualitative agreement.

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Enhancement of Classical and Neo-Classical Diffusion by Narrow Band Turbulence

Tihiro Ohkawa

1981 年 45 巻 3 号 p. 255-260
発行日: 1981年
公開日: 2011/03/04

DOIhttps://doi.org/10.1585/jspf1958.45.255

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サブミリ波散乱計測I

山下卓哉, 斉藤輝雄, 浜田泰司, 田中茂利, 水野皓司

1981 年 45 巻 3 号 p. 261-278
発行日: 1981年
公開日: 2011/03/04

DOIhttps://doi.org/10.1585/jspf1958.45.261

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The plasma diagnostics by means of the submillimeter wave scattering has been developed and applied successfully to the study of the low frequency instabilities of the tokamak plasma. As for the heterodyne detection system on 890 GHz band, Schottky barrier diodes, manufactured by Nippon Telephone and Telegraph Company, are exployed.
The voltage responsivity of the detector mount is about 170 V/W and the mixer temperature is determined to be 3 x 10⁴ K at 890 GHz.
Simple and long-life waveguide HCN laser is developed as a light source of which power is about 80 mW for the 2.4m discharge length.
The scattering apparatus is constructed by using these developed components and applied to the study of the scattering by the low frequency turbulence in the tokamak plasma. Main features of this observation are discussed.
This scattering apparatus is also applied to the study of the optoacoustic diffraction from the TPX Bragg Cell. The usefullness of the TPX Bragg Cell as the alignment and calibration of the FIR scattering apparatus is experimentally established.

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