The WT scheme, a piecewise polynomial force interpolation scheme with time-step dependency, is proposed in this paper for relativistic particle-in-cell (PIC) simulations. The WT scheme removes the lowest order numerical Cherenkov instability (NCI) growth rate for arbitrary time steps allowed by the Courant condition. While NCI from higher order resonances is still present, the numerical tests show that for smaller time steps, the numerical instability grows much slower than using the optimal time step found in previous studies. The WT scheme is efficient for improving the quality and flexibility of relativistic PIC simulations.

中文翻译：

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相对论单元格模拟中抑制数值Cherenkov不稳定性的时间步相关力插值方案

针对相对论的单元格粒子（PIC）仿真，本文提出了具有时间步长依赖性的分段多项式力插值方法WT方案。对于库仑条件所允许的任意时间步长，WT方案去除了最低阶的数值Cherenkov不稳定性（NCI）增长率。虽然仍然存在来自高次共振的NCI，但数值测试表明，对于较小的时间步长，数值不稳定性的增长要比以前研究中使用的最佳时间步长慢得多。WT方案对于提高相对论PIC仿真的质量和灵活性非常有效。