Development of Far-Infrared Laser Diagnostics for Simultaneous measurements of MHD Plasma Electron Density and Conductivity

开发用于同时测量 MHD 等离子体电子密度和电导率的远红外激光诊断技术

• 批准号: 02650137
• 负责人: MASUDA Mitsuharu
• 金额: $ 1.15万
• 依托单位: Kyushu University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1990
• 资助国家: 日本
• 起止时间: 1990 至 1991
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02650137/
• 关键词: Magnetohydrodynamics; MHD; Far-Infrared; Laser

In a large scale MHD channel, it will become important to get information on the fluctuations of the electron density and electrical conductivity, and on the correlation between them. The far-infrared (FIR) laser has offered a powerful diagnostic tool for this purpose. However, the optical setup for measuring the electron density and conductivity has been different ; the electron density is measured with the FIR laser interferometry and the conductivity with its beam transmissivity. Therefore, it has not been possible to measure electron density and conductivity simultaneously. Also, the main limitation of this diagnostic method is the slow response time of the pyroelectric detector that is used to detect the fringe shifts of the FIR laser interferometer. In this research project, we proposed a modified Michelson interferometer that enabled the simultaneous measurement of these two parameters. This modified interferometer was tested with a potassium-seeded flame, and also the pyroelectric detector was replaced by the Schottky-bonier diode that had a response time of the order of ten nanoseconds. With these modifications, the following results were obtained.1. To enable the simultaneous measurements of the electron density and conductivity, one beam splitter was added in the signal arm of the conventional Michelson interferometer. The results from this new system were quite satisfactory, and this system was proved very effective as an MHD diagnostic tool.2. To measure the fluctuation, the Schottky-banier-diode was used. The fluctuation of the electron density was measured by using this diode, and the density fluctuation of up to 5OkHz was measured. The upper limit of the measurable frequency depended on the speed of the analog-to-digital converter of the present system, and it was possible to measure the higher frequency by using a fast analog-to-digital converter.

在大规模 MHD 通道中，获取有关电子密度和电导率波动以及它们之间相关性的信息将变得非常重要。远红外 (FIR) 激光器为此提供了强大的诊断工具。然而，用于测量电子密度和电导率的光学装置有所不同；电子密度通过 FIR 激光干涉测量，电导率通过光束透射率测量。因此，不可能同时测量电子密度和电导率。此外，这种诊断方法的主要限制是用于检测 FIR 激光干涉仪条纹位移的热释电探测器的响应时间慢。在这个研究项目中，我们提出了一种改进的迈克尔逊干涉仪，可以同时测量这两个参数。这种改进的干涉仪用钾种子火焰进行了测试，并且热释电探测器也被响应时间为十纳秒量级的肖特基博尼尔二极管取代。经过这些修改，得到了以下结果： 1．为了能够同时测量电子密度和电导率，在传统迈克尔逊干涉仪的信号臂中添加了一个分束器。这个新系统的结果非常令人满意，并且该系统被证明作为MHD诊断工具是非常有效的。 2．为了测量波动，使用了肖特基巴尼尔二极管。使用该二极管测量电子密度的波动，并测量到高达5OkHz的密度波动。可测量频率的上限取决于本系统的模数转换器的速度，并且可以通过使用快速模数转换器来测量更高的频率。

项目成果

益田 光治: "MHDプラズマ計測用HCNレ-ザの開発" 電気学会、新・省エネルギ-研究会講演論文集. 101-106 (1991)

Mitsuharu Masuda：“用于 MHD 等离子体测量的 HCN 激光器的开发”日本电气工程师学会会议记录，新能源节约研究组 101-106 (1991)。

M.Masuda: "MHD Research at Kyushu University" USSR-Japan Joint Symposium on MHD. (1991)

M.Masuda：“九州大学MHD研究”苏联-日本MHD联合研讨会。

MASUDA, Mitsuharu: "Development of HCN Laser for MHD Plasma Diagnostics" Proc. New Energy Symp. 101-106 (1991)

MASUDA, Mitsuharu：“用于 MHD 等离子体诊断的 HCN 激光器的开发”Proc。

青木 俊之: "MHD発電機内の衝撃波と境界層の干渉に関する可視化研究" 可視化情報. 11. 227-230 (1991)

Toshiyuki Aoki：“MHD 发生器中冲击波与边界层之间的干涉的可视化研究”可视化信息。 11. 227-230 (1991)

AOKI, Toshiyuki: "Visualization of Shock Wave-Boundary Layer Interaction in MHD Generators" J. Visualization Soc. Japan. 11-2. 227-230 (1991)

AOKI，Toshiyuki：“MHD 发生器中冲击波与边界层相互作用的可视化”J. Visualization Soc。