The development of laser-plasma interaction program LAP3D on thousands of processors

Abstract

Modeling laser-plasma interaction (LPI) processes in real-size experiments scale is recognized as a challenging task. For explorering the influence of various instabilities in LPI processes, a three-dimensional laser and plasma code (LAP3D) has been developed, which includes filamentation, stimulated Brillouin backscattering (SBS), stimulated Raman backscattering (SRS), non-local heat transport and plasmas flow computation modules. In this program, a second-order upwind scheme is applied to solve the plasma equations which are represented by an Euler fluid model. Operator splitting method is used for solving the equations of the light wave propagation, where the Fast Fourier translation (FFT) is applied to compute the diffraction operator and the coordinate translations is used to solve the acoustic wave equation. The coupled terms of the different physics processes are computed by the second-order interpolations algorithm. In order to simulate the LPI processes in massively parallel computers well, several parallel techniques are used, such as the coupled parallel algorithm of FFT and fluid numerical computation, the load balance algorithm, and the data transfer algorithm. Now the phenomena of filamentation, SBS and SRS have been studied in low-density plasma successfully with LAP3D. Scalability of the program is demonstrated with a parallel efficiency above 50% on about ten thousand of processors. C 2015 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.

Simulations of laser plasma instabilities using a particle-mesh method

“…In the typical wave coupling method [36][37][38][39][42][43][44], the finite difference methods are adopted to solve the fluid equations directly. In contrast, the PM1D code does not directly solve the fluid equations for the plasma dynamics.…”

“…Therefore the fluid simulations are more suitable for the macroscopic long-time simulations of LPI. For example, the fluids codes PARAX [36], HERA [37], PF3D [38], LAP3D [39] and so on are developed for the largescale LPI simulations. In these codes, the paraxial (envelope) approximation is adopted in the wave equations of the electromagnetic waves and the plasma waves in the corresponding three-wave coupling models.…”

Parallel algorithm and parallel programming: from specialty to generality as well as software reuse

“…The parallel efficiency of five typical application softwares on TianHe-2 给出了 5 个超级并行应用软件在 "天河二号" 亿亿次计算机系统上的并行性能测试结果 2) , 它们均基于 JASMIN 框架研制, 其中: LAP3D 软件. 激光聚变应用软件之一[40] . 该程序可以模拟激光在等离子体中传播时所激发的 成丝、受激Raman 散射、受激 Brillouin 散射等不稳定性过程.…”