大尺度极高密度等离子体中相对论电子输运混合模拟的高效新型算法和验证研究

It is the objective of this project to investigate some key numerical techniques for simulating relativistic electrons transport in large-scale ultrahigh-density plasmas. In this research area, we outline the computable physical modeling, new efficient numerical algorithms, high-performance large-scale computational codes and physical verification. Our researches will focus to: 1) establish a complete theoretical description of the relativistic electron transport and ultrahigh-density plasma response system; 2) study new effective numerical algorithms and efficient implicit difference scheme to solve the relativistic electron kinetic equation, ultrahigh-density plasma ion and cold electron fluid energy equation, electromagnetic field Maxwell equations, the plasma material property equations, small-angle collisions between the electron and plasma particles as well as large-angle scattering equations; 3) break through key numerical methods to solve multi-physics multi-scale numerical difficulties of the mixing process for a long time computations; 4) realize high-performance relativistic electromagnetic fluid-particle-in-cell hybrid codes in tens of thousands of computer processor cores as well as validate their suitability from the physical principles and experimental data. The project is expected to solve the bottleneck problem in the large-scale simulation of the relativistic electron transport in ultrahigh density plasmas, and to obtain the original results in the study of new hybrid algorithms. Thereby our research will enhance the capability of independent innovation of China''s high-performance computational science.

研究大尺度极高密度等离子体中相对论电子输运过程的可计算物理建模、高效新型数值算法和高性能大规模计算程序，开展物理验证。具体包括：建立描述相对论电子输运和极高密度等离子体响应的完整理论体系；研究求解相对论电子动理学方程、极高密度等离子体离子和冷电子的双流体能量方程、电磁场Maxwell方程、等离子体材料物态性质方程、粒子之间小角度碰撞和大角度散射方程等的有效新型数值算法和高效率隐式差分格式，重点突破求解多物理、多尺度、多时标混合过程的数值难点；实现适合于上万处理器核的高性能相对论全电磁流体-粒子混合输运模拟，从物理原理和实验数据验证其可置性度。项目研究可望解决大尺度极高密度等离子体输运模拟中的瓶颈问题，并在新型混合算法研究中取得原创性成果，从而提升我国高性能计算科学自主创新能力。

获资助以来，重点开展了大尺度极高密度等离子体中的带电粒子产生与输运可计算物理建模、新型数值算法的研究和高性能大规模计算程序的研制，并开展了相关物理问题的研究。具体包括：1）提出了含相对论和背景等离子体集体效应的强流粒子束能量沉积物理处理方法，建立了全电磁粒子－流体混合的可计算物理模型，解决了强流粒子束与背景等离子体因能量和密度巨大差异引起的数值模拟难题，保证了物理模型的科学性并解决了模型的计算瓶颈。研制了强流粒子束产生程序LP2P-P/A、输运程序LP2P-B和能量沉积程序LP2P-F；通过程序间数据交换，形成了集成应用程序LP2P，实现了强流粒子束产生、输运和能量沉积的全过程模拟。2）系统研究了拍瓦激光驱动高品质强流粒子束产生和输运问题，获得了激光预脉冲、入射角、外磁场等对强流粒子束产额、能谱、能流的影响规律，发现了自生磁场、束流不稳定性对电子输运的影响规律，提出了通过靶结构和材料设计等提高电子束品质的物理方案。3）在高能量密度等离子体物理领域的研究中获得多项创新性成果，四年内已在本领域SCI核心杂志上发表论文60多篇(标注资助)，其中Nat. Commun. 1篇，Phys. Rev. Lett. 2篇。