Kaiser TB
Lawrence Livermore National Laboratory, University of California, Livermore, California 94550, USA.
Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics. 2000 Jan;61(1):895-905. doi: 10.1103/physreve.61.895.
A scheme is presented for laser beam evolution and power deposition on three-dimensional unstructured grids composed of hexahedra, prisms, pyramids, and tetrahedra. The geometrical-optics approximation to the electromagnetic wave equation is used to follow propagation of a collection of discrete rays used to represent the beam(s). Ray trajectory equations are integrated using a method that is second order in time, exact for a constant electron-density gradient, and capable of dealing with density discontinuities that arise in certain hydrodynamics formulations. Power deposition by inverse-bremsstrahlung is modeled with a scheme based on Gaussian quadrature to accommodate a deposition rate whose spatial variation is highly nonuniform. Comparisons with analytic results are given for a density ramp in three dimensions, and a "quadratic-well" density trough in two dimensions.
本文提出了一种用于在由六面体、棱柱体、棱锥体和四面体组成的三维非结构化网格上进行激光束演化和功率沉积的方案。利用电磁波方程的几何光学近似来跟踪用于表示光束的离散光线集合的传播。使用一种时间上二阶、对于恒定电子密度梯度精确且能够处理某些流体动力学公式中出现的密度不连续性的方法来积分光线轨迹方程。通过逆轫致辐射进行的功率沉积采用基于高斯求积的方案进行建模，以适应空间变化高度不均匀的沉积速率。给出了与三维密度斜坡和二维“二次阱”密度谷的解析结果的比较。
