An Alternative Approach to Incorporating Laser Pulses in Particle-in-Cell Simulations

Numerical modeling of electromagnetic waves is a critical component of particle-in-cell simulation of laser–plasma interactions. Traditionally, laser pulses have been either launched from simulated antennas or initialized in their entirety in the computational domain. Relying on the electromagnetic field update to advance the laser pulse, however, imposes high computational expense in situations where the computational domain must cover many Rayleigh ranges. As an alternative, we demonstrate that laser pulses can be incorporated directly into the particle push provided that numerical dispersion is accounted for both in terms of the phase velocity and the ratio between the electric and magnetic fields. This approach can reduce the size of the computational domain and eliminate the need for multiboundary antennas, facilitating, for example, the modeling of flying-focus pulses.