Particle-in-cell codes are the most widely used simulation tools for kinetic studies of ultra-intense laser-plasma interactions. Using the motion of a single electron in a plane electromagnetic wave as a benchmark problem, we show surprising deterioration of the numerical accuracy of the PIC algorithm with increasing normalized wave amplitude for typical time-step and grid sizes. Two significant sources of errors are identified: strong acceleration near stopping points and the temporal field interpolation. We propose adaptive electron sub-cycling coupled with a third order temporal interpolation of the magnetic field and electric field as an efficient remedy that dramatically improves the accuracy of the particle integrator.

细胞内粒子代码是用于超强激光-等离子体相互作用动力学研究的最广泛使用的仿真工具。使用单个电子在平面电磁波中的运动作为基准问题，我们显示出对于典型的时间步长和网格大小，随着归一化波幅的增加，PIC算法的数值精度会出现令人惊讶的下降。识别出两个重要的误差源：停车点附近的强加速度和时域插值。我们提出自适应电子子循环与磁场和电场的三阶时间插值相结合，作为有效地改善粒子积分器精度的有效方法。