多组分稠密等离子体中电子—离子关联效应对能量弛豫的影响

The correlation effect between electrons and ions (e-i) in the multi-component dense plasmas (MCDP) not only is related to the basic research field, including fusion physics, astrophysics, and others, but also is the importantly fundamental research issue in the high-energy laser/particle experiments and inertial confinement fusion (ICF) researches. In this project, we plan to theoretically and systematically study the influence of e-i correlation effect on the energy relaxation in MCDP. It mainly includes four parts: Firstly, the local field correction (LFC) method in the will be developed, in which the e-i correlation effect is taken into account self-consistently. Based on this kinetic method, the e-i pair distribution function, e-i energy relaxation rate, and other important physical quantities will be numerically calculated, and then the dependence of e-i energy relaxation on the e-i correlations in MCDP will be clarified; Secondly, the multiple scattering theory will be developed, and the multiple scattering cross section containing the e-i correlation effect will be derived. Combining with the LFC, the influence of e-i correlation effect on the stopping power of MCDP will be explored theoretically; Thirdly, the theories of Green's function and T-matrix suitable for the MCDP will be developed, from which the influence of e-i correlation effect on the dynamically structure factor, dielectric function, and other matters will be systematically investigated; In the last part, we will also perform the molecular dynamics (MD) simulations on the problems of energy relaxation in MCDPs, which are the focus in ICF research. Furthermore, combining the MD results with the theoretical models mentioned above, the e-i correlation effects therein will be profoundly illustrated, and the validity and applicability of these kinetic models will also be verified carefully. We hope these researches could promote the theoretical and experimental studies about the dense plasmas in ICF field.

等离子体中的电子—离子关联效应不仅涉及聚变物理学、天体物理学等基础研究领域，同时也是高能激光、高能粒子束实验以及惯性约束聚变（ICF）等重大工程应用关注的重要基础研究内容。本项目拟从多个层面系统研究多组分稠密等离子体中的电子—离子关联效应对能量弛豫的影响。主要包括：发展多组分稠密等离子体的局域场修正理论，自洽的引入电子—离子关联效应，并计算关联函数、电子—离子能量弛豫速率等，阐明其对关联效应的依赖关系；发展多组分稠密等离子体的多重散射理论，导出包含关联效应的多重散射截面，分析关联效应对等离子体阻止本领的影响；发展多组分稠密等离子体的格林函数理论，导出关联函数的格林函数表述，研究关联效应对动态结构因子的影响；对ICF相关的稠密等离子体能量弛豫问题开展分子动力学模拟研究，结合上述理论模型分析其中的关联效应，进而验证模型的正确性和适用范围。预期这些研究将推动ICF稠密等离子体的理论和实验研究。

惯性约束聚变（ICF）内爆过程中，等离子体将跨越很宽的温度密度范围，不同组分之间存在严重的能量非平衡效应，α-粒子在等离子体中的能量沉积更是与热核聚变靶丸能否顺利实现点火息息相关。本项目的实施过程中，我们深入发展了若干ICF相关的多组分稠密等离子体中的能量弛豫与阻止本领模型，包括：阻止本领的动态局域场修正模型、包含核散射干涉效应的阻止本领多重散射模型、阻止本领的杂质散射模型、以及相对论的能量沉积的模型，等。通过对这些动理学模型的理解和分析，我们深刻地理解了电子—离子关联效应、温度非平衡效应、核散射干涉效应、杂质效应、相对论效应等重要物理效应对稠密等离子体中的能量弛豫过程的影响机制，合理地解释了一些相关的实验结果。此外，我们还初步发展了适用于温稠密等离子体对带电粒子的阻止本领的第一性原理计算模拟技术，发展了适用于温稠密等离子体的X射线汤姆逊散射（XRTS）谱的数值模拟技术。这些数值模拟程序和技术有望为我国 ICF 靶设计提供具有高置信度的阻止本领和XRTS程序，以及更加精确的等离子体状态参数，也为我国在神光II、神光III等大型激光装置上开展相关的实验研究提供了有益的理论和技术支撑。因此本项目的研究内容和成果为我们理解和控制ICF内爆动力学及点火有着非常重要的意义，同时也会推动其他学科相关领域的发展，并在ICF新型能源靶设计以及国防安全等领域存在潜在的应用价值。