大尺度黑腔冕区等离子体动力学特性及其影响

Hohlraum plasma and its kinetic behavior are vital to study the high temperature hohlraum radiation source used in high energy density physics (HEDP). They determine the efficiency and quality of laser transmission, scattering and energy deposition, thus affecting the temporal, spatial and spectral features of the x-ray source. The characteristics of the radiation driven ablation, shock wave and hydrodynamic instability are very sensitive to the property and behavior of the hohlraum plasma. The difficulties that U.S. National Ignition Campaign (NIC) encountered indicate that the influence of hohlraum plasma on several important physical mechanisms is essential to design and establish hohlraum radiation source with high confidence level used in HEDP research. . This project is aimed at the hohlraum plasma within two specific regions. For laser directly incident high Z corona, we intend to obtain its precise feature such as ionization, density, temperature and dynamic behavior. The plasma property and emission feature at non-local thermodynamic equilibrium (NLTE), and the effect of non-local electron transport will be studied separately through delicately designed experiment. Also, the movement of the high Z corona and its mix with the filling gas will be studied in detail using quasi two dimensional hohlraum. For blow-off plasma generated from capsule ablator, the plasma flow and its effect on stimulated Raman scattering (SRS) within the laser path will be studied..

黑腔等离子体状态及其动力学行为是理解和研究黑腔辐射场特性的首要因素，它直接影响激光-黑腔的能量耦合效率，影响激光的传输、散射、能量沉积位置，影响X射线转换和输运，影响黑腔辐射场的时、空及能谱特性，进而非常敏感地影响辐射驱动的冲击波、流体力学不稳定性和内爆等过程的物理特性。本项目拟针对黑腔内部两个特征区域的等离子体开展细致研究。对于激光直接辐照的高Z冕区等离子体，拟开展等离子体状态、动力学行为及能量平衡研究。通过分解实验，研究非平衡高Z等离子体的状态参数与X光发射特性，区分解耦非平衡离化分布和电子热传导过程；研究准二维黑腔内高Z冕区等离子体的运动行为及其与填充气体的混合。对于靶丸烧蚀飞散等离子体，拟开展等离子体状态、动力学行为研究，分析其对激光光路上等离子体状态的改变，研究激光光路相对靶丸的截距对激光受激拉曼散射的影响。

黑腔等离子体状态及其动力学行为是理解和研究黑腔辐射场特性的首要因素，对激光惯性约束聚变的黑腔物理及后续过程有着深刻的影响。本项目针对黑腔内部两个特征区域的等离子体开展了细致研究，发展建立了以光学汤姆逊散射为主的黑腔内部等离子体状态精密表征的实验技术；首次观测到黑腔内部不同密度扰动的来源及其影响；通过对黑腔激光辐照Au冕区运动特性的细致研究，促进了高发射实用模型的建立和校验；基于高发射实用模型，再现了实验激光辐照Au冕区等离子体状态的反常特性，证实了激光辐照Au冕区的三维非对称结构和高发射模型的准确性；深入研究了黑腔不同关键区域等离子体状态对激光等离子体不稳定性的影响，体现了激光辐照Au冕区、气体、样品烧蚀飞散三类等离子体对LPI的作用和影响。