Gridless quasistatic model for efficient simulation of plasma-based accelerators

The accurate modeling of plasma-based accelerators relies on costly numerical simulations due to the complexity of laser-plasma and beam-plasma interactions. Several strategies can highly reduce the computational cost compared to 3D first-principles particle-in-cell simulations, such as exploiting the near axial symmetry and quasistatic nature of plasma wakefields in many practical cases. Here, we propose a quasistatic algorithm that enables the modeling of axially symmetric plasma wakes without the need of a numerical grid. The gridless approach allows extremely fine features to be resolved without a dramatic increase in computational cost. This is critical, e.g., for the design of future plasma-based colliders with nanometer emittance beams. The proposed model has been implemented in the Wake-T code, where it is coupled to a laser envelope solver and a particle beam pusher to enable the efficient simulation of laser- and beam-driven plasma accelerators.