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Characterization of ultra high energy density plasma generated by a pinch discharge

箍缩放电产生的超高能量密度等离子体的表征

基本信息

批准号：
05680385
负责人：
HIRANO Katsumi
金额：
$ 1.02万
依托单位：
Gunma 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：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05680385/
关键词：
Ultra high energy density plasma Soft X-ray source Intense X-ray source Z pinch discharge Plasma focus High current discharge

项目摘要

In this study, the ultra high energy density plasma is produced by the plasma focus discharge using a capacitor bank of 1.6 * 30 muF (150 kJ) with which discharge current more than 1 MA is possible. Relationship between plasma evolution and soft X-ray emission is obtained with developing several diagnostic systems.Main results are following :(1) In the plasma focus devices, a satisfactory pinch easily occurs when pure hydrogen is employed. We accomplished the pinch with high Z gas by decoupling the initial stage of the discharge and the pinch stage, stating the discharge in pure hydrogen then puffing the high Z gas just before the pinch stage.(2) We developed an imaging Bragg spectrograph with which a monochromatic soft X-ray image is obtained specifying its wavelength. Record of the image is usually carried out using such as Kodak direct exposure film whose handling is rather troublesome. We devised a method to obtain the linear relationship between the soft X-ray intensity and the blackness of the image of commonly used photographic film such as Kodak TRI-X.(3) A pinhole camera which enables a quantitative measurement of the soft X-ray intensity in 2-dimension with a narrow pass band was developed. This makes possible to obtain the plasma parameters such as the electron temperature and the electron density of the high energy density plasma.(4) In the plasma focus device with the gas puff system, it was observed that the electron-density and temperature are in the order of 10^<20>/cm^3 and keV,respectively. The soft X-ray source mainly consists of the hydrogen-like and the helium-like ions. When argon is used as a puffed gas, 10^<21> photons in K-lines were observed per discharge in the direction of the electrode axis.

在本研究中，用1.6×30MUF(150kJ)的电容器组进行等离子体聚焦放电，可以产生大于1 mA的超高能量密度等离子体。通过研制几种诊断系统，得到了等离子体演化与软X射线发射的关系。主要结果如下：(1)在等离子体聚焦装置中，当使用纯氢时，容易产生令人满意的夹持。我们通过分离放电初始阶段和收缩阶段，在纯氢中描述放电，然后在收缩阶段之前吹气高Z气体，从而实现了高Z气体的收缩。(2)我们研制了一台成像Bragg光谱仪，利用它可以获得指定波长的单色软X射线图像。图像的记录通常使用诸如柯达直接曝光胶片，其处理相当麻烦。我们设计了一种方法来获得软X射线强度与柯达Tri-X等常用照相胶片图像黑度之间的线性关系。(3)研制了一种能够在窄通带内定量测量二维软X射线强度的针孔相机。这使得获得高能密度等离子体的电子温度和电子密度等等离子体参数成为可能。(4)在带喷气系统的等离子体聚焦装置中，观察到电子密度和温度分别为10^&lt；20&gt；/cm^3和keV量级。软X射线源主要由类氢离子和类氦离子组成。当使用Ar作为膨化气体时，在电极轴方向上每次放电观察到K线中的10^&lt；21&gt；光子。