A fast 3D raytracing algorithm in spherical symmetry coordinates

Abstract Three dimensional (3D) raytracing is essential for the numerical simulation of inertial confinement fusion. Nearly all major hydrodynamic radiation codes use the Kaiser’s algorithm(Kasier 2000 Phys. Rev. E 61 , 895) to solve the 3D raytracing. This algorithm is a general method adaptable to any computational mesh type. However, when applied to a two dimensional (2D) or one dimensional (1D) spherical symmetry mesh, the hydrodynamic mesh must be replicated into a 3D mesh, and curved surfaces should be decomposed into triangular and quadrilateral ‘subfaces’. To accelerate and simplify the calculation of 3D raytracing, a novel algorithm that eliminates the need for replicating the hydrodynamic mesh in spherical symmetry coordinates is presented. It is shown that the algorithm can significantly reduce computational cost while preserving precision in 1D or 2D spherical coordinates. It is applicable not only to the laser energy deposition, but also to particle tracing problems in 1D or 2D spherical coordinates, such as the Monte Carlo algorithm for solving the radiation transfer or the alpha particle transport.