Spectroscopic Diagnostics Using Line-Radiation in Laser Driven Non-equilibrium Plasmas in a Ti-doped Silica Aerogel Foam Target

Experiments were performed at the Jupiter Laser Facility at LLNL, where x-ray spectroscopic measurements among other data were acquired from sub-critical-density, Ti-doped silica aerogel foams driven by a 2ω laser at ~ 5x10¹⁴ W/cm². The main objective is to study the effect of external B-field in thermally insulating the hot plasma and investigating line-radiation in multi-keV, non-equilibrium plasmas. The near term goal is to infer a time-integrated temperature at several positions along the laser propagation axis for several B-field cases and observe any sensitivity to density for estimated plasma conditions of n_e/n_c ~ 0.2 and T_e ~ 1 keV with 4.5% of Ti by atomic fraction in SiO₂ foam target. We present time-integrated synthetic Ti spectra employing a recently developed non-LTE collisional-radiative spectroscopic model with detailed multi-frequency radiation transport scheme to diagnose the spectroscopic data. This approach was successfully used to replicate observed x-ray line spectra and diagnose plasma conditions from various wire-array and gas puff implosions on the Z machine at Sandia National Laboratories.