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

该项目的目的是产生超高能量密度等离子体（>10^4 J/cm^3），并阐明等离子体中产生高强度软X射线的机制。我们研究了等离子体开发诊断工具的非接触和二维成像方法具有高的空间和时间分辨率。他们是;（1）不使用变像管而采用新概念构建的多通道（包括红外线、可见光和软X射线）成像系统。该系统能够同时以条纹和分帧模式记录脉冲软X射线图像。(2)本文介绍了一种基于微通道板（MCP）的连续四帧针孔摄像系统，其曝光时间为200 ps，帧间时间为2.5ns，空间分辨率为0.1mm。(3)采用凸晶体（RbAP，r = 12.5mm）的软X射线成像谱仪，利用喷气式等离子体聚焦装置，在放电电流的作用下，对喷气的氖、氩、氪气体进行了强压缩。电子温度和电子密度分别为-2 keV和-10 ^<22>/cm ^3（能量密度&gt;3 x 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。对于一个较低的原子序数的气体，如氖，软X射线发射之前，由宏观不稳定性的增长似乎是m=0型的捏柱中断。相反，软X射线发射发生在pisma柱破裂后，当氩或氪被膨化。这与离子束和电子束的产生相吻合，离子束和电子束由等离子体柱的破坏引起的高电压加速。事实表明，等离子体只有通过压缩到能辐射氖的K-射线的温度才能被充分加热。然而，在氩气和kripton加热是不够的压缩，和束等离子体相互作用是必不可少的K-应辐射。

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.