新型电荷守恒算法在大规模粒子模拟中的应用

Application of a novel charge-conservation method used in large-scale parallel computation for fully electromagnetic Particle-In-Cell simulation

摘要:

介绍了一种粒子沿折线(zigzag-line)运动的守恒型PIC算法在自编三维全电磁粒子模拟大规模并行程序NEPTUNE3D中的实现与应用情况。相对于经典PIC算法，该算法不需要修正电场，可以避免大型矩阵求逆问题，使得程序鲁棒性更高；相对其他守恒型算法，该算法不需判断语句，代码执行效率更高，更适合大规模并行计算环境。通过与经典PIC算法对比，给出采用zigzag-line守恒型PIC算法的NEPTUNE3D程序对磁绝缘线振荡器天线一体化模型与太赫兹折叠波导行波管2个实际算例的验证测试结果、应用效果，结果表明：zigzag-line守恒型PIC算法模拟结果正确可靠，相对经典PIC算法，大大缩短了计算时间，显著提升了器件模拟设计效率。

Abstract:

A novel charge-conservation method with particle zigzag-line moving is introduced and it is implemented and applied in a large-scale parallel code named NEPTUNE3D for fully electromagnetic Particle-In-Cell(PIC) simulation programmed by authors. Compared with the classical PIC method, this zigzag-line charge-conservation method does not need Boris-correction which involves large linear-equations for solving problem, so it has a better robustness. Compared with other charge-conservation methods, this zigzag-line charge-conservation method does not need any judgment sentence, so its code executive efficiency is higher and it is suitable for massively parallel computation. Compared with the classical PIC method, two real devices are simulated and tested by using NEPTUNE3D with zigzag-line charge-conservation method, one is the entire high power microwave tube including magnetic transmission line oscillator and antenna, the other one is a terahertz folded waveguide travelling-wave-tube. The zigzag-line charge-conservation method simulation results are correct and agree with the classical PIC method well. Moreover, as computation duration being shortened notablely, device-design and simulation efficiency could be boosted obviously by using this new zigzag-line charge-conservation method.