嵌入神经网络的等离子体粒子模拟算法
Plasma Particle Simulation Algorithm Embedded with Neural Networks
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摘要: Particle-In-Cell(PIC)粒子模拟方法是开展等离子体动理学物理研究的重要数值模拟方法之一。本文构建一个由相空间到静电场的端到端神经网络模型,并将其嵌入至一维静电PIC粒子模拟算法中,以替代传统泊松求解器,实现了神经网络算法和传统粒子模拟方法的有效融合。开展等离子体双流不稳定性物理问题的模拟计算,通过观测算法运行过程中相空间演化及电势能增长趋势,验证了该方法的可行性,并测试获得其计算性能。研究结果表明: 在短时长训练集的输入训练情况下,该方法能够实现4倍数据集时长的准确模拟。同时,该方法在一定程度上能够突破显式粒子模拟时间步长的约束条件,进而可以有效减少模拟问题的总迭代计算次数。Abstract: The Particle-In-Cell (PIC) particle simulation method is one of the important numerical simulation methods for conducting plasma kinetic physics research. In this paper, by constructing an end-to-end neural network model from the phase space to the electrostatic field and embedding it into the one-dimensional electrostatic PIC particle simulation algorithm, the effective integration of the neural network algorithm and the traditional particle simulation method is achieved by replacing the traditional Poisson solver. The feasibility of the method is verified by carrying out simulations of the plasma two-stream instability physics problem, observing the phase space evolution and the growth trend of potential energy during the running of the algorithm, and its computational performance is tested and obtained. The results show that the method is able to achieve an accurate simulation with four times the dataset duration in the case of input training with short duration training set. At the same time, the method is able to break the constraint of explicit particle simulation time step to a certain extent, which in turn can effectively reduce the total number of iterative computations of the simulation problem.