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Production of super high density plasma by a high current Z discharge

通过大电流 Z 放电产生超高密度等离子体

基本信息

批准号：
08680498
负责人：
HIRANO Katsumi
金额：
$ 1.6万
依托单位：
Gunma University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08680498/
关键词：
Soft X-ray microsope Soft X-ray source Impululsuve soft X-rays Z-pinch discharge High current discharge Image processing

项目摘要

Purpose of the project is production of a super high energy density plasma(>10^4 J/cm^3) and elucidation of the mechanism of the highly intense soft X-ray generation in a plasma. We investigated the plasma developing diagnostic tools for non-contact and 2-dimensional imaging methods with high spatial and temporal resolution. They are ; (1) A multichannel (including infra red, visible and soft X-rays) imaging system built by a new concept without using an image converter tube. The system enables to record a pulsed soft X-ray image in streak and framing mode simultaneously. (2) A geted pinhole camera system based on an MCP for successive four framing images of 200 ps in exposure time, 2.5 ns in interframe lime and 0.1 mm in spatial resolution. (3) A soft X-ray imaging spectrometer with a convex crystal (RbAP, r = 12.5 mm).Using the plasma focus facility with the gas puff, puffed neon, argon and krypton are strongly compressed by the discharge current. The electron temperature and the electron density were -2 keV and -10 ^<22>/cm^3 (energy density >3 x 10 ^4 J/cm^4), respectively. The life time of the plasma column was several times longer than that of an ordinary (gas embedded) plasma focus. For a puffed gas with a lower atomic number like neon, the soft X-rays were emitted before disruption of the pinched column by a growth of macroscopic instability seemed to be m=0 type. On the contrary, the soft X-ray emission occurred after disruption of the pisma column when argon or krypton is puffed. This coincided to generation of the ion and electron beam which were accelerated by a high voltage induced by disruption of the plasma column. The facts suggest that the plasma is sufficiently heated only by the compression to the temperature to radiate the K-shall lines in neon. However, in argon and kripton heating is not sufficient by compression, and the beam plasma interaction is indispensable for K-shall radiation.

该项目的目的是产生超高能量密度等离子体（bbb10 ^4 J/cm^3），并阐明等离子体中高强度软x射线产生的机制。我们研究了等离子体发展诊断工具的非接触和二维成像方法，具有高空间和时间分辨率。他们是；(1)采用新概念构建的不使用图像转换管的多通道（包括红外、可见光和软x射线）成像系统。该系统能够同时以条纹和分幅模式记录脉冲软x射线图像。(2)基于MCP的连续4幅曝光时间为200ps、帧间时间为2.5 ns、空间分辨率为0.1 mm的定向针孔相机系统。(3)带有凸晶（RbAP, r = 12.5 mm）的软x射线成像光谱仪。利用等离子体聚焦装置和气体雾化装置，被雾化的氖、氩和氪被放电电流强烈压缩。电子温度和电子密度分别为-2 keV和-10 ^<22>/cm^3（能量密度>3 × 10 ^4 J/cm^4）。等离子体柱的寿命比普通（气体嵌入）等离子体焦点的寿命长几倍。对于像氖这样原子序数较低的膨化气体，软x射线是在压缩柱被宏观不稳定性的增长破坏之前发射的，似乎是m=0型的。相反，当氩气或氪气被吹胀时，pisma柱破裂后出现软x射线发射。这与离子和电子束的产生相吻合，离子束和电子束是由等离子体柱破裂引起的高电压加速产生的。事实表明，等离子体只有被压缩到足以辐射氖中的K-shall线的温度时才足够加热。然而，在氩气和克里普顿中，通过压缩加热是不够的，而束等离子体相互作用对于K-shall辐射是必不可少的。