[PEM17-P01] Mitigation of the numerical Cherenkov instability by using the Cole-Karkkainen field solver for PIC simulations
Keywords:numerical Cherenkov instability, relativistic shock, PIC simulation
We have developed a technique to mitigate the NCI for relativistic shock simulations by adopting a specific CFL number with a special combination of the PIC algorithms (Vay & Godfrey, 2013; Xu et al., 2013; Ikeya & Matsumoto, 2015). We have confirmed this novel properties of mitigating the NCI for highly relativistic cases (the Lorentz factor gamma > 10, Iwamoto et al., 2017), but for mildly relativistic cases (gamma < 5). In this presentation, we present another implementation of the technique using Cole-Karkkainen electromagnetic field solver (Cole, 2002; Karkkainen et al., 2006; Vay et al., 2011). We derived a dispersion relation of an implicit C-K solver and confirmed the implementation into our 2D PIC code. We found that the implicit C-K solver has novel properties of mitigating the NCI not only for ultra relativistic cases, but also for mildly relativistic cases (gamma=2). We present detailed properties of this scheme along with an application to relativistic shock simulations.