Spectroscopic characterization of ultrashort laser driven targets incorporating both Boltzmann and particle-in-cell models

Abstract

A model that solves simultaneously both the electron and atomic kinetics was used to generate synthetic X-ray spectra to characterize high intensity ultrashort-laser-driven target experiments. A particle-in-cell simulation was used to model the laser interaction for both cluster and foil targets and provided the initial electron energy distribution function (EEDF) for a Boltzmann solver. Previously reported success in the spectroscopic characterization of an irradiated Ar cluster target has motivated the authors to apply this technique in a feasibility study to assess the possibility of recording time resolved spectra of a 10 micron Ti foil target irradiated by a 500 fs, I= 1.0 × 1018W/cm2 short-pulse laser. Though this model suggests that both Ar cluster and Ti foil plasmas are held in a highly non-equilibrium state for both the EEDF and the ion level populations for several picoseconds, the spectral line features of the foil experiment was shown to evolve too quickly to be seen by current ultrafast time resolved spectrometers.