Numerical Cherenkov radiation is a well-known problem of FDTD PIC codes caused by numerical dispersion errors creating spurious radiation around accelerated particles. It is usually dealt with by complex numerical schemes and low-pass filters. In this study we look at a simple way to circumvent this problem for wakefield accelerators simulations by only modifying the field interpolation algorithm. Taking advantage of the highly directional nature of the numerical Cherenkov radiation, we make sure that the resultant force created by the spurious radiation is as close to zero as possible for the accelerated electrons, negating its effects on the accelerated bunch without actually suppressing the numerical radiation. Applying the above to laser wakefield acceleration simulations, we observe both a reduction and a stabilization of the beam normalized emittance during the acceleration process as well as an improved regularity of the oscillating electrons trajectories which might help to further understand radiation processes such as betatron.

Cherenkov数值辐射是FDTD PIC代码的一个众所周知的问题，它是由数值色散误差在加速粒子周围产生寄生辐射引起的。通常通过复杂的数值方案和低通滤波器来处理。在这项研究中，我们研究了一种仅通过修改场插值算法来规避尾流加速器仿真问题的简单方法。利用数字Cherenkov辐射的高度方向性，我们可以确保由杂散辐射产生的合力对于加速电子尽可能接近于零，从而消除了其对加速束的影响，而没有实际抑制数字辐射。将以上内容应用于激光尾波加速模拟，