X-ray Studies of Exotic Novel States of Solid-Density Matter Created with 4th Generation Light Sources

用第四代光源产生的固体密度物质的奇异新状态的 X 射线研究

• 批准号: EP/H035877/1
• 负责人: Justin Wark
• 金额: $ 92.98万
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2010
• 资助国家: 英国
• 起止时间: 2010 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FH035877%2F1
• 关键词: ray; Studies; Exotic; Novel; States

Over the past year or so there has been a revolution in X-ray science, in that new sources of soft and hard X-rays have been developed that are ten billion times brighter than those produced by synchrotrons. These novel sources emit extremely short (sub 100fsec) pulses of x-rays, and can be focussed to very small spots. As the pulses are so short, the power in the light is enormous - for the brief duration of the emission the power in the light is equivalent to that in a fair-sized electrical power station. When all this power is focussed to a small spot, enormous intensities of x-rays impinge upon the target in its path - intensities that have hitherto never been produced in the X-ray regime. In the last few months we have performed some of the first experiments aimed at understanding how matter reacts to such intense X-ray light, and the aim of this proposal is to vastly further that understanding. What we have already found is that the intensity is so great that an electron from every atom in the target can be knocked out by the X-rays, and this can alter the X-ray properties of the material itself - indeed, by this method we have made a so-called saturable absorber. What is of fundamental interest to us is that as the electrons re-fill the core holes, they provide information about the electronic structure of this exotic and highly-ionized state, providing completely new insight into the physics of very dense, yet very hot material. This material (warm dense matter) is of interest in that the thermal energies and electronic energies (the coulomb potential) are comparable, making its properties extremely difficult to calclulate. This situation - where the thermal and coulombic energies compete - also occurs in the initial stages of inertial confinement fusion, and is also part of the physics that is relevant to the understanding of the interior of the giant planets - thus there are many reasons for wishing to understand it better. The intense X-rays give a unique opportunity to understand such matter, as within femtoseconds they make a particular state - very hot electrons but cold ions, at a well defined density. Watching this state evolve ( by looking at the fluorescence, and monitoring the absorption as a function of time) gives detailed information on the electronic structure. For example, with highly ionized aluminium, we have an unusual situation at the highest intensities where a particular aluminium ion that undergoes recombination is now doing so with neighbours that themselves are still ionized. This drastically alters the shape of the fluorescence emission in a way which has much to do with how the fluorescence signal from an alloy is altered as the compound composition changes. Thus this research will provide unique insight into the electronic structure of matter at hundreds of thousands of degrees kelvin, yet still at solid density.

在过去一年左右的时间里，X射线科学发生了一场革命，新的软X射线和硬X射线源已经开发出来，比同步加速器产生的X射线亮100亿倍。这些新的源发出极短（低于100飞秒）的X射线脉冲，并可以聚焦到非常小的斑点。由于脉冲如此之短，光中的功率是巨大的-对于短暂的发射持续时间，光中的功率相当于一个中等规模的发电站。当所有这些能量都聚焦到一个小光点上时，巨大强度的X射线就会沿着它的路径撞击到目标上--这种强度在X射线体系中从未产生过。在过去的几个月里，我们进行了一些旨在了解物质如何对如此强烈的X射线光做出反应的第一批实验，而这项提议的目的是大大促进这种理解。我们已经发现，X射线的强度是如此之大，以至于靶中每个原子的电子都可以被X射线击倒，这可以改变材料本身的X射线特性--事实上，通过这种方法，我们已经制造出了一种所谓的可饱和吸收体。我们最感兴趣的是，当电子重新填充核心空穴时，它们提供了关于这种奇异和高度电离状态的电子结构的信息，为非常致密但非常热的材料的物理学提供了全新的见解。这种材料（温暖的致密物质）的兴趣在于热能和电子能量（库仑势）是可比的，使得它的性质非常难以计算。这种情况--热能和库仑能竞争--也发生在惯性约束聚变的初始阶段，也是与理解巨行星内部相关的物理学的一部分--因此有很多理由希望更好地理解它。强烈的X射线提供了一个独特的机会来理解这种物质，因为在飞秒内，它们会产生一种特定的状态-非常热的电子，但冷离子，密度很好。观察这种状态的演变（通过观察荧光，并监测作为时间函数的吸收）可以提供有关电子结构的详细信息。例如，对于高度电离的铝，我们在最高强度处有一种不寻常的情况，即经历复合的特定铝离子现在正在与其本身仍然电离的邻居进行复合。这极大地改变了荧光发射的形状，其方式与来自合金的荧光信号如何随着化合物组成的变化而改变有很大关系。因此，这项研究将提供独特的洞察物质的电子结构在几十万开氏度，但仍然在固体密度。

项目成果

Observation of Reverse Saturable Absorption of an X-ray Laser

X 射线激光反向饱和吸收的观察

• DOI: 10.3204/pubdb-2017-13877
• 发表时间: 2017
• 作者: Cho B

Simultaneous diagnosis of radial profiles and mix in NIF ignition-scale implosions via X-ray spectroscopy

通过 X 射线光谱同时诊断 NIF 点火级内爆中的径向分布和混合

• DOI: 10.1063/1.5000774
• 发表时间: 2017
• 期刊: Physics of Plasmas
• 影响因子: 2.2
• 作者: Ciricosta O

Measurements of continuum lowering in solid-density plasmas created from elements and compounds.

• DOI: 10.1038/ncomms11713
• 发表时间: 2016-05-23
• 期刊: Nature communications
• 影响因子: 16.6
• 作者: Ciricosta O;Vinko SM;Barbrel B;Rackstraw DS;Preston TR;Burian T;Chalupský J;Cho BI;Chung HK;Dakovski GL;Engelhorn K;Hájková V;Heimann P;Holmes M;Juha L;Krzywinski J;Lee RW;Toleikis S;Turner JJ;Zastrau U;Wark JS
• 通讯作者: Wark JS

Detailed model for hot-dense aluminum plasmas generated by an x-ray free electron laser

• DOI: 10.1063/1.4942540
• 发表时间: 2016-02-01
• 期刊: PHYSICS OF PLASMAS
• 影响因子: 2.2
• 作者: Ciricosta, O.;Vinko, S. M.;Wark, J. S.
• 通讯作者: Wark, J. S.

Measurements of continuum lowering in solid-density plasmas created from elements and compounds

由元素和化合物产生的固体密度等离子体的连续降低的测量

• DOI: 10.3204/pubdb-2016-06351
• 发表时间: 2016
• 作者: Ciricosta O