A PIC-Fluid Hybrid Algorithm for Multiscale Simulations of Laser-Plasma Interactions

A recently introduced algorithm for performing integrated kinetic simulations of the fast ignition approach to laser fusion is reviewed. The integrated algorithm uses a conventional fully electromagnetic relativistic particle-in-cell algorithm in vacuum and plasma up to a density well above cutoff for the incident laser, above which density the plasma is sufficiently collisional so that light waves and electron plasma waves are unimportant and a simplified physics model is justified that leads to improved computational efficiencies. Integrated comprehensive kinetic simulation of fast ignition is rendered more practical with this two-region algorithm. Professor C. K. Birdsall was a pioneer in computational plasma physics and enthusiastically championed the expansion of its use for discovery science and to simulate plasma phenomena in a wall-to-wall manner.