Development and Implementation of a Numerical Ray-tracing Laser Energy-Deposition Model for the PSC particle-in-cell (PIC) code

PSC, a particle-in-cell (PIC) code, is being used to directly simulate experiments involving high-energy-density (HED) plasma plumes. HED plasma plumes are formed in the laboratory by ablating solid-density targets with high-intensity lasers. Such laboratory experiments and their simulations are used for fundamental plasma studies. Currently, PSC uses an ad hoc plasma heating operator to represent the amount of energy a laboratory laser deposits as it propagates through a plasma. The ad hoc heating operator is derived from the plasma density profile found in DRACO, an independent radiation hydrodynamic simulation with a well-developed laser energy absorption model (W. Fox, et al, Phys. Plasmas 2018). To expand the scope of experiments that PSC can run and remove its dependency on DRACO, a new numerically calculated ray-tracing laser energy-deposition model was developed for PIC codes and implemented into PSC using existing theory on optical absorption by a plasma. The energy deposited per cell from the new model was benchmarked against and was found to be in excellent agreement with DRACO and analytical solutions for both shallow and highly oblique laser incidence angles. Additionally, energy is well-conserved by the new heating operator for large temporal domains.