A Subgrid Algorithm for the Efficient Modeling of Plasma-Based Accelerators with Ion Motion Using Quasi-Static Particle-in-Cell Codes

Ion motion has a strong impact on the quality preservation of electron beams in plasma-based colliders. While being crucial for the advance of plasma-based accelerators, the modeling of the physics of interest is highly challenging due to the large disparity of the relevant transverse length scales. To correctly model plasma-based collider schemes with ion motion, a high transverse resolution must be employed in particle-in-cell simulations, which, conventionally, entails significant computational costs. By introducing a refined subgrid in the witness beam region in a quasi-static particle-in-cell code, significant computational savings can be achieved. This numerical approach allows for the accurate modeling of plasma-based colliders with ion motion in the blowout regime while allowing for an orders of maznitude computational speedup.