Electron Density and Conductivity Measurements of MHD Plasma by an FIR Laser

使用 FIR 激光器测量 MHD 等离子体的电子密度和电导率

• 批准号: 10650182
• 负责人: MASUDA Mitsuharu
• 金额: $ 2.24万
• 依托单位: KYUSHU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10650182/
• 关键词: MAGNETOHYDRODYNAMICS; MHD; FAR-INFRARED; LASER

To estimate the performance of an MHD generator, it is necessary to know the behavior of the plasma parameters. The electron density and conductivity are the most important parameters governing the generator characteristics. These have been measured by electrostatic probes and/or rf probes. The insertion of probes into plasma, however, inevitably disturb the flow field inside an MHD channel, and the obtained values are thought to have large errors.In the present research, the electron density and conductivity are measured with the HCN far-infrared(FIR)laser. The target plasma is generated by the shock tunnel. The driver and driven sections of the shock tunnel are filled with helium and argon, respectively. The shock Mach number is varied by changing the gas pressure, and the plasma generated in the stagnation section upstream of the channel is used as a target. The Michelson interferometer is used to measure the fringe shift due to the plasma, from that the electron density is calculated. Also, the transmissivity of the FIR laser beam through the plasma is measured, and the conductivity is determined from the measured electron density and transmissivity. Major improvement of this FIR diagnostic technique is achieved by applying a Schottky barrier diode for the signal detection. This diode has very fast response time, an order of a few nano seconds, and with this capability, it gas become possible to clarify the temporal variation of the plasma with high accuracy.

为了估计MHD发电机的性能，有必要知道等离子体参数的行为。电子密度和电导率是决定发生器特性的最重要的参数。这些已经通过静电探针和/或射频探针测量。然而，探针插入等离子体中，不可避免地会干扰MHD通道内的流场，并且所获得的值被认为是有很大的误差。靶等离子体由激波风洞产生。激波风洞的驱动段和被驱动段分别充满氦气和氩气。通过改变气体压力来改变激波马赫数，并将在通道上游的停滞段中产生的等离子体用作目标。用迈克尔逊干涉仪测量等离子体引起的条纹位移，并由此计算出电子密度。此外，测量通过等离子体的FIR激光束的透射率，并且从测量的电子密度和透射率确定电导率。该FIR诊断技术的主要改进是通过应用肖特基势垒二极管进行信号检测来实现的。这种二极管具有非常快的响应时间，几纳秒的数量级，并且具有这种能力，它可以高精度地澄清等离子体的时间变化。

项目成果

矢野栄宣: "遠赤外レーザー法による衝撃波管生成MHDプラズマのパラメータ測定"平成11年度衝撃波シンポジウム前刷集. (印刷中). (2000)

Yoshinobu Yano：“使用远红外激光方法测量激波管产生的 MHD 等离子体的参数”1999 年冲击波研讨会预印本集（2000 年）。

INOUE, Masahiro: "Mesurements of Disturbance in Hish Speed Flow with Laser-induced Fluorescence Method"JSME Journal Series B. Vol.65, No.631. 948-954 (1999)

INOUE, Masahiro：“用激光诱导荧光法测量高速流动中的扰动”JSME 期刊系列 B. 第 65 卷，第 631 期。

KASHITANI, Masashi: "Numerical and Experimental Investigations of Supersonic Jets from Sootblower Nozzle"JSME Intemational Journal Series B. Vol.41, No.2. 375-380 (1998)

KASHITANI, Masashi：“吹灰器喷嘴超音速射流的数值和实验研究”JSME 国际期刊系列 B. 第 41 卷，第 2 期。

井上雅弘: "レーザ蛍光法による高速気流中のじょう乱伝ぱ測定"日本機械学会論文集 B編. 65・631. 948-954 (1999)

Masahiro Inoue：“使用激光荧光法测量高速气流中的扰动传播”日本机械工程学会会刊，卷 B.65, 631.948-954 (1999)

Taro Handa: "Fine structure on shock oscillation in supersonic nozzle"Proc. 4th KSME-JAME Fluid Engi. Conf.,. 445-448 (1998)

半田太郎：“超音速喷管激波振荡的精细结构”Proc。