Colaïtis A, Duchateau G, Ribeyre X, Maheut Y, Boutoux G, Antonelli L, Nicolaï Ph, Batani D, Tikhonchuk V
Université de Bordeaux-CNRS-CEA, Centre Lasers Intenses et Applications, UMR 5107, 351 Cours de la Libération, 33400 Talence, France.
Dipartimento SBAI, Università degli Studi di Roma "La Sapienza," Via Antonio Scarpa, 14, 00161 Rome, Italy.
Phys Rev E Stat Nonlin Soft Matter Phys. 2015 Oct;92(4):041101. doi: 10.1103/PhysRevE.92.041101. Epub 2015 Oct 29.
We present a formulation of the model of laser-plasma interaction (LPI) at hydrodynamical scales that couples the plasma dynamics with linear and nonlinear LPI processes, including the creation and propagation of high-energy electrons excited by parametric instabilities and collective effects. This formulation accounts for laser beam refraction and diffraction, energy absorption due to collisional and resonant processes, and hot electron generation due to the stimulated Raman scattering, two-plasmon decay, and resonant absorption processes. Hot electron (HE) transport and absorption are described within the multigroup angular scattering approximation, adapted for transversally Gaussian electron beams. This multiscale inline LPI-HE model is used to interpret several shock ignition experiments, highlighting the importance of target preheating by HEs and the shortcomings of standard geometrical optics when modeling the propagation and absorption of intense laser pulses. It is found that HEs from parametric instabilities significantly increase the shock pressure and velocity in the target, while decreasing its strength and the overall ablation pressure.
我们提出了一种在流体动力学尺度下的激光 - 等离子体相互作用（LPI）模型公式，该公式将等离子体动力学与线性和非线性LPI过程相耦合，包括由参数不稳定性和集体效应激发的高能电子的产生和传播。该公式考虑了激光束的折射和衍射、碰撞和共振过程导致的能量吸收，以及受激拉曼散射、双等离子体衰变和共振吸收过程导致的热电子产生。热电子（HE）的输运和吸收在多群角散射近似下进行描述，该近似适用于横向高斯电子束。这种多尺度内联LPI - HE模型用于解释多个冲击点火实验，突出了热电子对靶材预热的重要性以及在对强激光脉冲的传播和吸收进行建模时标准几何光学的不足之处。研究发现，参数不稳定性产生的热电子显著增加了靶材中的冲击压力和速度，同时降低了其强度和整体烧蚀压力。
