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 obj ective is to study the effect of external B- field in thermally insulating the hot plasma and investigating line-radiation in multi -ke V, non-equilibrium plasmas for applications in ICF hohlraums and targets, high-photon-energy x-ray sources for radiography, as well as in the MagLIF scheme. The near term goal is to use spectroscopy 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 ne/nc ~ 0.2 and Te~ 1 keV with 4.5% of Ti by atomic fraction in SiO 2 foam target. Spatially resolved, time-integrated spectral simulations using accurate atomic and radiation transport models will provide synthetic Ti K - and L-shell spectra with which to compare and analyze the available data. We present synthetic Ti spectra employing a recently developed non-LTE collisional-radiative spectroscopic model with detailed multi-frequency radiation transport scheme. This approach was successfully used to replicate observed xray line spectra and diagnose plasma conditions from various wire arrays and gas puff implosions on the Z machine at Sandia National Laboratories.