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

该项目的目的是生产超高能量密度等离子体(&gt；10^4J/cm^3)，并阐明在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的诊断工具，用于非接触和高空间和时间分辨率的二维成像方法。它们是：(1)用新概念建造的多通道(包括红外、可见光和软X射线)成像系统，而不使用成象转换管。该系统能够同时以扫描和分幅模式记录脉冲软X射线图像。(2)基于MCP的连续四帧图像获取针孔相机系统，曝光时间为200ps，帧间时间为2.5 ns，空间分辨率为0.1 mm。(3)带凸晶的软X射线成像谱仪(RbAP，r=12.5 mm)，利用等离子体聚焦装置产生的气体，在放电电流的作用下，对膨胀的Ne、Ar和氪进行强烈的压缩。电子温度为-2keV，电子密度为-10×10~(-4)J/cm~(-4)。等离子体柱的寿命比普通(气体埋入)等离子体焦点的寿命长好几倍。对于像Ne这样原子序数较低的膨化气体，软X射线是在宏观不稳定性的增长破坏夹紧柱之前发射的，似乎是m=0型。相反，软X射线发射发生在PISMA柱破裂后，当Ar或氪被膨胀时。这与离子和电子束的产生是一致的，而离子和电子束的产生是由等离子体柱中断引起的高电压加速的。事实表明，只有压缩到足以辐射霓虹线的温度，等离子体才能得到足够的加热。然而，在Ar和Klipton中，压缩加热是不够的，束流等离子体相互作用是K-Se辐射不可缺少的。

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.