LULI2000 - Ionization competition effects on K-shell emission spectra of mixture plasmas (B. Loupias)
Heating of thin foil targets by a high power laser at intensities of 1017 -1019W/cm2 has been studied as a method for producing high temperature, high density samples to investigate X-ray opacity and equation of state . The mechanisms governing the propagation of the laser-accelerated electrons and their energy deposition into dense materials have been extensively investigated over the past years, mainly in the framework of the Fast Ignition approach to Inertial Confinement Fusion (ICF) . Previous campaign in PICO2000 allowed us to determine the temperature range accessible in buried targets. Al and Ti K shell spectra interpretation leads to around 1keV temperature at solid density. In addition to these measurements, time resolved spectra are consistent with such temperature as it is the key parameter to fit emission time duration. Our results showed that a complex atomic physics is required to reproduce the experimental data (accurate impact broadening, detailed description of the atomic states subjected to external ionic distribution of micro-electric field in the plasmas, accurate plasma screening and ionization potential depression). In such condition it is thus interesting to investigate mixing conditions between high and low Z element in which high Z element will dominate radiative properties and low Z element will be strongly impacted. These studies are in particular interest for ICF problematic corresponding to hot spot conditions and dealing with doped ablator mixing in D-T fuel.