Hybrid Kinetic Method for Laser-Plasma Interaction in the Presence of Strong Spatial Gradients

We propose to develop an advanced software tool to study the interaction of intense laser beam with plasma, which is either pre-formed or produced during the interaction process. Such interaction is characterized by large spatial gradients due to plasmaexpansion from near-solid density to rarefied plasma, self-induced electromagnetic fields with scales varying from skin depth to Debye length and beyond, and extremely non-equilibrated distribution of charged particles.Typicaly used PIC method has several shortcomings: statistical noise, poor compatibility with adaptive grid and collisions handling, inability to capture sharp gradients and energetic tails of particle populations. Time averaging is used to mitigate theseproblems, but this approach is non-applicable for the strongly non-equilibrated transient processes. Kinetic Vlasov and Fokker-Planck methods utilize grid-based approaches. Unfortunately they suffer from large numerical diffusion, and have enormousrequirements on the directly accessible memory to store distribution functions. Several orders of spatial/temporal differences in plasma temperature and density make adaptive capability a natural requirement.This project is to develop a relativistic electromagnetic PIC-Vlasov Hybrid method combined with the Adaptive Mesh method to guarantee automatic resolution of the propagating laser front and the expanding plume. Parallel computer code efficiency will bedemonstrated using the Delta Search Labs supercomputer facility. The developed software could be directly applied to many important areas. It could be used to investigate, interpret and optimize operation of various processes, schemes and devices, which use intensive laser-plasma interaction. The applications includelaser micro- and macro-propulsion thrusters, inertial fusion devices, X-ray and UV-radiation sources, accelerators of charged particles, medical tomographs and radiology machines, isotope and high-harmonics generators. The proposed software can also beused as part of a larger code, complementing non-kinetic techniques.