中Z温/热稠密物质X光吸收光谱特性与原子结构

Warm/hot dense matter (WHDM) is one of the main research objects of high energy density physics (HEDP).The study of characteristics for the WHDM has important applications in the related research fields such as inertial fusion science and astrophysics, and is also an extremely challenging scientific project in atomic physics. The present project will focus on the x-ray absorption spectrum and atomic structure of the medium-Z WHDM such as Fe,Al or Si to study its charateristics, mainly including :1) based on the ns-pulse intense laser, developing the shock compression technique and multi-heating technique driven by the intense X-ray radiation field, to produce the WHDM, then to measure its near-edge x-ray absorption spectrum and line x-ray spectrum; 2) developing the theoretical models to consider the electron excitation and ionization effects, the diadiabatic energy exchanging between ions and electrons in WHDM, as well as the nucleus’ movement, which can be used to simulate accurately the ionic structure and dynamics in WHDM,as well as to calculate the statistical properties for WHDM in broad state of temperature and density; 3) elucidating quantitatively the warm/hot dense environment effects on the atomic structure and radiative characteristics in pressure- or thermal ionized WHDM, and revealing the physical mechanism. The present project will significantlly promote the researching abilities and understanding level of WHMD, and also contribute to the atomic physics and HEDP development in China.

温/热稠密物质是高能量密度物理的主要研究对象之一,其物性研究是具有重要科学意义的原子物理学挑战前沿基础课题，在惯性约束聚变和天体物理等研究领域具有重大应用需求。本项目将聚焦于中Z元素(铁、铝或硅)温/热稠密物质的X光吸收光谱特性与原子结构开展物性研究，主要包括：1）发展利用纳秒级强激光产生的高温X光辐射场冲击压缩技术和复合加载技术，在实验室产生接近和大于固体密度的温/热稠密物质，测量其X光近边吸收谱与线吸收谱；2）发展包含电子激发、电离、电子离子非绝热能量交换等物理效应以及原子核运动的第一性原理分子动力学理论方法，准确模拟温热稠密物质中的微观原子结构及其动力学演化，并计算其宽区范围的宏观统计性质；3）定量阐述压致电离或热电离主导的稠密物质中，环境对原子结构和辐射过程的影响，揭示其物理机制。本项目的研究，将整体显著提升我国在极端条件原子物理学和高能量密度物理学的研究能力和认识水平。

温/热稠密物质是高能量密度物理的主要研究对象之一，其物性研究具有重要科学意义，是原子物理学的挑战性前沿课题，同时在惯性约束聚变和天体物理等研究领域具有重大应用需求。本项目采用理论、数值模拟和实验研究紧密结合的方法开展研究，建立了从0.1倍固体密度到最高6倍固体密度的中Z温/热稠密物质实验室产生技术与高分辨X射线吸收光谱精密测量技术，获得了温稠密硅的吸收边与近边吸收X光光谱随稠密状态的演化规律，阐述了电离势下降及稠密环境效应对热稠密铝等离子体的K壳层吸收特征谱的影响，探索了激光直接驱动的热稠密等离子体辐射吸收光谱实验研究新方法；发展和完善了宽区温热稠密物质第一性原理分子动力学理论模型，完成了稠密等离子体环境中的原子结构和辐射跃迁参数的程序编制和大规模计算，对较宽温度、密度范围的等离子体环境效应影响进行了较系统的评估。本项目研究提升了对稠密等离子体环境效应影响原子结构和辐射特性的物理认识，并为建立温热稠密物质的状态表征技术奠定了基础。