Extended particle absorber for efficient modeling of intense laser-solid interactions

TL;DR

This paper introduces an extended particle absorber boundary condition for particle-in-cell simulations, significantly reducing computational costs while maintaining accuracy in modeling intense laser-solid interactions.

Contribution

It presents a novel extended particle boundary condition that improves efficiency and accuracy in laser-plasma interaction simulations by reducing particle count requirements.

Findings

Achieves accurate simulation results with only 20% of particles.

Effectively models long-pulse laser interactions in overdense plasmas.

Reduces computational expense in large-scale plasma simulations.

Abstract

An extended thermal particle boundary condition is devised to more efficiently and accurately model laser-plasma interactions in overdense plasmas. Particle-in-cell simulations of such interactions require many particles per cell, and a large region of background plasma is often necessary to correctly mimic a semi-infinite plasma and avoid electron refluxing from a truncated plasma. For long-pulse lasers of many picoseconds, such constraints can become prohibitively expensive. Here, an extended particle boundary condition (absorber) is designed that instantaneously stops and re-emits energetic particles streaming toward the simulation boundary over a defined region, allowing sufficient time and space for a suitably cool return current to develop in the background plasma. Tunable parameters of the absorber are explained, and simulations using the absorber with a 3-ps laser are shown to accurately reproduce those of a causally separated boundary while requiring only 20% the number of particles.