A new field solver for modeling of relativistic particle-laser interactions using the particle-in-cell algorithm

A customized finite-difference field solver for the particle-in-cell (PIC) A algorithm that provides higher fidelity for wave-particle interactions in intense electromagnetic waves is presented. In many problems of interest, particles with relativistic energies interact with intense electromagnetic fields that have phase velocities near the speed of light. Numerical errors can arise due to (1) dispersion errors in the phase velocity of the wave, (2) the staggering in time between the electric and magnetic fields and between particle velocity and position and (3) errors in the time derivative in the momentum advance. Errors of the first two kinds are analyzed in detail. It is shown that by using field solvers with different k-space operators in Faraday's and Ampere's law, the dispersion errors and magnetic field time-staggering errors in the particle pusher can be simultaneously removed for electromagnetic waves moving primarily in a specific direction. The new algorithm was implemented into OSIRIS by using customized higher-order finite-difference operators. Schemes using the proposed solver in combination with different particle pushers are compared through PIC simulation. It is shown that the use of the new algorithm, together with an analytic particle pusher (assuming constant fields over a time step), can lead to accurate modeling of the motion of a single electron in an intense laser field with normalized vector potentials, eA/mc(2), exceeding 10(4) for typical cell sizes and time steps. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

A customized finite-difference field solver for the particle-in-cell (PIC) A algorithm is introduced to improve the fidelity of wave-particle interactions in intense electromagnetic waves. By analyzing and addressing dispersion errors and time-staggering errors, the new algorithm allows for more accurate modeling of particle motion in electromagnetic fields. This algorithm, implemented with higher-order finite-difference operators, shows promising results in simulations compared to traditional methods.