Efficient modeling of ion-motion in LWFA using electromagnetic Particle-in-Cell code with mesh refinement

Understanding of the physics associated with Ion motion in LWFA is crucial for building future linear colliders based on plasma based acceleration. For the parameters required for these applications, ions move significantly, particularly in the vicinity of the injected electron beam. Accurate modeling of the physics of interest is highly challenging due to large disparity in the transverse length scales, which requires a large number of grid cells in the transverse direction to resolve small-scale features of interest. Previous works have employed quasi-static Particle-in-cell codes with mesh refinement in the witness beam region for simulations of ion motion in plasma based accelerators. In this work, we present the progress and challenges in simulations of ion motion in laser-driven plasma accelerators using the electromagnetic PIC code WarpX, with mesh refinement features in full 3D cartesian geometry. We further investigate the accuracy and performance of the code with comparisons of results with and without mesh refinement.