Roberto C. Mancini

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The time-dependent gradient structure of a laser-compressed, high-energy-density plasma has been determined using a method based on the simultaneous analysis of time-resolved x-ray monochromatic images and x-ray line spectra from Ar-doped D2 implosion cores. The analysis self-consistently determines the temperature and density gradients that yield the best(More)
Mixing of plastic ablator material, doped with Cu and Ge dopants, deep into the hot spot of ignition-scale inertial confinement fusion implosions by hydrodynamic instabilities is diagnosed with x-ray spectroscopy on the National Ignition Facility. The amount of hot-spot mix mass is determined from the absolute brightness of the emergent Cu and Ge K-shell(More)
Modeling the Stark broadening of spectral lines in plasmas is a complex problem. The problem has a long history, since it plays a crucial role in the interpretation of the observed spectral lines in laboratories and astrophysical plasmas. One difficulty is the characterization of the emitter's environment. Although several models have been proposed over the(More)
Nearly a century ago it was recognized that radiation absorption by stellar matter controls the internal temperature profiles within stars. Laboratory opacity measurements, however, have never been performed at stellar interior conditions, introducing uncertainties in stellar models. A particular problem arose when refined photosphere spectral analysis led(More)
We use a parallel multi-objective genetic algorithm to drive a search and reconstruction spectroscopic analysis of plasma gradients in inertial confinement fusion (ICF) implosion cores. In previous work, we had shown that our serial multi-objective Genetic Algorithm was a good method to solve two-criteria X-ray spectroscopy diagnostics problems. However,(More)
The fuel layer density of an imploding laser-driven spherical shell is inferred from framed x-ray radiographs. The density distribution is determined by using Abel inversion to compute the radial distribution of the opacity kappa from the observed optical depth tau. With the additional assumption of the mass of the remaining fuel, the absolute density(More)
We present a modeling study of x-ray line polarization in plasmas driven by high-intensity, ultrashort duration pulsed lasers. Electron kinetics simulations of these transient and nonequilibrium plasmas predict non-Maxwellian and anisotropic electron distribution functions. Under these conditions, the magnetic sublevels within fine structure levels can be(More)
Hot dense capsule implosions driven by Z-pinch x rays have been measured using a approximately 220 eV dynamic Hohlraum to implode 1.7-2.1 mm diameter gas-filled CH capsules. The capsules absorbed up to approximately 20 kJ of x rays. Argon tracer atom spectra were used to measure the T(e) approximately 1 keV electron temperature and the n(e) approximately(More)
Measurements of iron-plasma transmission at 156+/-6 eV electron temperature and 6.9+/-1.7 x 10(21) cm(-3) electron density are reported over the 800-1800 eV photon energy range. The temperature is more than twice that in prior experiments, permitting the first direct experimental tests of absorption features critical for understanding solar interior(More)