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Spectroscopic Measurements of Turbulent Electric Fields in An Intense Relativistic Electron Beam-Plasma System

强相对论电子束等离子体系统中湍流电场的光谱测量

基本信息

批准号：
02452271
负责人：
MASUZAKI Masaru
金额：
$ 0.96万
依托单位：
Kanazawa University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
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

项目摘要

The main purpose of this research project was to establish spectroscopic methods for measurements of turbulent electric fields in an intense relativistic electron beam-plasma system. Followings are summary of results obtained: 1. An 8-channel spectroscopic system composed of a 0.5 m Ebert-type monochromator(Jarrell-Ash), a rod lens, a fiber bundle and eight photomultipliers has been prepared. Resolution of each channel is 0.03 nm and the minimum separation between neighboring channels is 0.04 nm. 2. Forbidden lines 447.0 nm and 667.8 nm were observed near He I 447.2 nm and 492.2 nm lines, respectively, when an intense beam was injected into a plasma produced in helium gas of 20 m Torr by a pair of plasma guns. The appearance of forbidden lines is an evidence of the turbulent state of the plasma. 3. It was found from Stark shift measurements that there were electric fields even as high as 110-125 kV/cm, and that the distribution of the electric fields was a Gaussian. 4. The turbulent state continued to exist even about 1 mus after the beam ceased to propagate. 5. The results of spectroscopic measurements may be explained by the recently proposed two-component model which states that there are many cavitons in the plasma which repeat creation by nucleation, collapse and burn out, and that the turbulent state consists of cavitons and background weak waves. 6. A N_2-laser for pumping a dye laser was fabricated. The dye laser is to be used for a plasma satellite method with laser induced florescence. 7. When the ratio of the beam electron density and the plasma electron density was higher than about 0.01, high-power broadband microwaves were emitted, and current enhancement phenomenon appeared. However, there was no dependence on this density ratio of the results of the spectroscopic measurements.

本研究项目的主要目的是建立测量强流相对论电子束-等离子体系统中湍流电场的光谱方法。1.研制了由0.5m Ebert型单色仪(Jarrell-Ash)、棒透镜、光纤束和8个光电倍增管组成的8通道光谱系统。每个通道的分辨率为0.03 nm，相邻通道之间的最小间隔为0.04 nm。2.用一对等离子体枪在20m托尔氦气中产生的等离子体中注入强流束流，在He I的447.0 nm和667.8 nm附近分别观察到了447.2 nm和492.2 nm的禁带。禁线的出现是等离子体湍动状态的证据。3.斯塔克位移测量发现，即使在110-125千伏/厘米的范围内也存在电场，电场的分布呈高斯分布。4.即使在光束停止传播后约1微秒，湍流状态仍然存在。5.光谱测量的结果可以用最近提出的双组分模型来解释，该模型指出，等离子体中存在许多空穴，这些空穴通过成核、坍塌和燃烧而重复产生，湍流状态由空穴和背景弱波组成。6.研制了用于泵浦染料激光器的N_2激光器。染料激光器将用于激光诱导荧光等离子体卫星方法。7.当束流电子密度与等离子体电子密度之比大于0.01时，产生高功率宽带微波，并出现电流增强现象。然而，光谱测量结果的密度比并不依赖于此。