Diagnostics for laser-scale MHD power generation system using faraday rotation.

在大尺度MHD通道中，获取电子密度和电导率的涨落及其相互关系的信息将变得非常重要。远红外(FIR)激光为这一目的提供了强大的诊断工具，该研究小组建立了能够同时测量电子密度和电导率的方法。本研究的目的是利用法拉第旋转原理对红外激光测量方法进行改进，使其适用于大型实验装置。然而，在进行实验研究的同时，设计了一种新的干涉仪，可以测量电子密度和电导率的大波动。该干涉仪在传统的迈克尔逊干涉仪的基础上增加了另一条干涉路径，能够测量条纹漂移超过2pi的大起伏。因此，本项目的目的略有改变，以阐明这种新型干涉仪的特点，并取得了以下结果。为了建立稳定的远红外干涉仪，设计并制作了新型氢化氢激光器。实验证明，该激光器工作稳定，可用于干涉仪系统。设计并制作了基于全新概念的干涉仪。这比传统的迈克尔逊干涉仪多了一条干涉仪路径。同时，利用肖特基势垒二极管进行了起伏检测。编制了考虑多路干涉光路影响的软件。结果表明，该系统能够成功地测量电子密度和电导率的起伏。

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, and the method was establish by this research group that enabled the simultaneous measurements of electron density and conductivity. The purpose of this research project was to improve FIR-laser method to be applicable to the large-scale experimental facility by using Faraday rotation principle. While the experimental research was being done, however, the new interferometer was devised that could measure the large fluctuation of the electron density and conductivity. This interferometer adds another interferometric path to the conventional Michelson interferometer, and is capable of measuring the large fluctuation with the fringe shifts over 2pi. Therefore, the purpose of this project was changed slightly to clarify the characteristics of this new interferometer, and the following results were obtained.1. To establish the stable FIR interferometer, the new HCN laser was designed and made. This laser was proved to operate successfully and shown to be used in the interferometer system.2. The interferometer based on the entirely new concept was designed and made. This has one more interferometer path in the conventional Michelson interferometer. Also, the Schottky-barrier-diode was used to detect the fluctuation. The software that took into account the multiple interferometer path was made. It was shown that the present new system could successfully measure the fluctuations of the electron density and conductivity.