大电流X箍缩产生高亮度脉冲软、硬X射线点光源的基础研究

High intensity soft and hard point X-ray sources are the key diagnostics to probe the dynamics of the newly proposed low-Z thick liner Z-pinch plasmas, high-Z materials under strong pressures, and etc. The high current driven X-pinch is a potential way to produce the high intensity soft and hard point X-ray sources with high-efficiency and low-cost. But it is difficult to form a single point soft X-ray source stably, and the understanding of the characteristics of the hard X-ray source is very limited. To solve these problems and according to the fact that soft and hard X-ray radiations from X-pinch are correlated, the researches on the fine evolutions, physical mechanics and adjusting methods of the high current driven X-pinch will be carried out. The key problem to be solved is the regulation mechanism of X-pinch’s dynamics and its radiation characteristics under high current. The investigations will be conducted in the following order: firstly, the fine evolutions of the Mega ampere X-pinch will be obtained; secondly, the formation mechanisms of the multiple hot spots and the hard X-ray radiation will be revealed; finally, the methods, such as using a Mega ampere generator with a low impedance and a two-stage X-pinch load, will be tested in order to produce a single soft X-ray point source, and the hard X-ray source’s matched load configurations under Mega ampere generators with different impedances will be obtained and the methods to adjust their radiation characteristics will be explored. The project will further help to master the radiation characteristics of the high current driven X-pinch and the methods to adjust them. These prospective achievements are supposed to provide the basis and conditions for the applications of high intensity soft and hard X-ray point sources in high energy density physics and other scientific frontiers.

为了对低Z元素厚套筒新型Z箍缩负载等离子体、以及高压下高Z元素材料动力学过程等进行精密诊断，需要发展高亮度的脉冲软、硬X射线点光源。大电流X箍缩是一种高效低成本的可能实现方式，但目前尚存在单个软X射线点源难以稳定产生的问题，而且对硬X射线辐射特性的认识更为不足。针对此，本项目拟基于X箍缩软、硬X射线辐射的关联性，围绕大电流X箍缩演化及辐射的控制机理这一核心问题，开展兆安电流X箍缩精细演化、物理机理和调控方法的研究：从大电流X箍缩精细演化出发，进一步研究软X射线形成多点源及后续产生硬X射线辐射的物理机理，最后研究低阻抗兆安源驱动二级X箍缩等实现软X射线单点源的新方法，以及不同阻抗兆安电流源上的硬X射线点源匹配负载及其辐射特性的调控手段。通过研究可深入揭示和掌握大电流X箍缩的X射线辐射特性和调控方法，为基于X箍缩产生的高亮度软、硬X射线点光源在高能量密度物理等科学前沿领域的应用提供基础和条件。

大电流X箍缩是一种产生高亮度脉冲软、硬X射线点光源的有效方式，但大电流下产生脉冲软X射线单点源的调控方法有限，且人们对X箍缩硬X射线辐射特性的认识不足。针对上述问题，本项目聚焦大电流X箍缩演化及辐射的控制机理这一核心问题，紧密围绕X箍缩软、硬X射线辐射产生的关联关系，开展兆安电流X箍缩精细演化、物理机理和调控方法的研究。.（1）实验获得了数百千安-兆安级大电流X箍缩动力学行为及辐射特性，基于1MA “强光一号”装置、400-800kA“秦-1”装置，实验研究了百千安至兆安电流下X箍缩的演化行为及其辐射特性，获得了X箍缩负载质量与X射线辐射时刻、强度的定标关系。.（2）总结了大电流下X箍缩多脉冲、多点源热斑辐射规律，获得了“二次箍缩”、“局部箍缩”产生多脉冲、以及“长波长扰动”、“短波长扰动”产生多点源的实验规律，掌握了混合型X箍缩丝长度对软X射线辐射稳定性和硬X射线产额的影响。.（3）提出并建立了基于预脉冲电流的X箍缩辐射特性调控方法，研究了预脉冲电流等对丝阵X箍缩、混合型X箍缩的影响。预脉冲电流作用下，丝阵X箍缩的各金属丝、混合型X箍缩的单丝将都形成芯晕结构，主脉冲电流将驱动晕层内爆至丝芯时电流转移，丝芯电流前沿增加，有利于产生更稳定的辐射。.（4）建立了X箍缩软、硬X射线点投影照相系统，获得了丝阵动态物体的X箍缩软射线点投影图像，以及电子芯片等的硬X射线点投影照相的图像。.通过本项目研究，有助于丰富X箍缩的物理认识及其辐射特性的调控方法，为研制脉冲电流驱动的脉冲软、硬X射线点光源提供理论依据和技术支撑。本项目共发表SCI论文7篇，申请国家发明专利1项，在IEEE等离子体科学国际会议、脉冲功率国际会议做特邀报告各1次，培养优青、卓青各1人。建立的X箍缩X射线源在强脉冲辐射环境模拟与效应实验室的Z箍缩实验诊断和探测器测试标定中得到应用。