Nichols K A, Hu S X, White A J, Goncharov V N, Mihaylov D I, Collins L A, Shaffer N R, Karasiev V V
Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA.
Department of Physics and Astronomy, University of Rochester, Rochester, New York 14623-1299, USA.
Phys Rev E. 2023 Sep;108(3-2):035206. doi: 10.1103/PhysRevE.108.035206.
Nonlocal electron transport is important for understanding laser-target coupling for laser-direct-drive (LDD) inertial confinement fusion (ICF) simulations. Current models for the nonlocal electron mean free path in radiation-hydrodynamic codes are based on plasma-physics models developed decades ago; improvements are needed to accurately predict the electron conduction in LDD simulations of ICF target implosions. We utilized time-dependent density functional theory (TD-DFT) to calculate the electron stopping power (SP) in the so-called conduction-zone plasmas of polystyrene in a wide range of densities and temperatures relevant to LDD. Compared with the modified Lee-More model, the TD-DFT calculations indicated a lower SP and a higher stopping range for nonlocal electrons. We fit these electron SP calculations to obtain a global analytical model for the electron stopping range as a function of plasma conditions and the nonlocal electron kinetic energy. This model was implemented in the one-dimensional radiation-hydrodynamic code lilac to perform simulations of LDD ICF implosions, which are further compared with simulations by the standard modified Lee-More model. Results from these integrated simulations are discussed in terms of the implications of this TD-DFT-based mean-free-path model to ICF simulations.
非局域电子输运对于理解激光直接驱动（LDD）惯性约束聚变（ICF）模拟中的激光与靶耦合至关重要。辐射流体力学程序中当前用于非局域电子平均自由程的模型是基于几十年前开发的等离子体物理模型；需要改进这些模型，以便在ICF靶内爆的LDD模拟中准确预测电子传导。我们利用含时密度泛函理论（TD-DFT），在与LDD相关的广泛密度和温度范围内，计算聚苯乙烯所谓传导区等离子体中的电子阻止本领（SP）。与修正的Lee-More模型相比，TD-DFT计算表明非局域电子的SP较低，阻止范围较高。我们对这些电子SP计算结果进行拟合，以获得一个关于电子阻止范围的全局解析模型，该模型是等离子体条件和非局域电子动能的函数。此模型被应用于一维辐射流体力学程序lilac中，以进行LDD ICF内爆模拟，并进一步与标准修正Lee-More模型的模拟结果进行比较。根据这个基于TD-DFT的平均自由程模型对ICF模拟的影响，讨论了这些综合模拟的结果。
