Experimental and simulation studies on radiative properties of uranium planar target coated with an ultrathin aluminum layer

Abstract

An ultrathin aluminum (Al) layer is proposed to be coated on the surface of the uranium (U) planar target for preventing the oxidization of U and optimizing the hard x-ray spectrum. Comparative experiments using several planar targets with different materials are implemented on the Shenguang-III prototype laser facility to study their radiative properties. Under the laser intensity of W cm−2, we observe that the U target coated with 30 nm thick Al produces almost the same peak intensity of the total x-ray flux and decreases the hard x-ray fraction by 38.5% compared to the U target coated with 100 nm thick gold. Simulations using XRL2D (2D radiation hydrodynamic code) interpret the measured results and indicate that the radiative property of Al-coated U approaches that of pure U, which theoretically has a high laser to x-ray conversion efficiency and a quasi-Planckian spectrum. Based on our analysis, Al-coated U is a promising material of the ignition hohlraum and should have many applications in high energy density physics.

Experimental and simulation studies on gold bubble movement in gas-filled hohlraums

“…The simulation depends on the atomic model and the modelings of multiple physical processes, including electron thermal conduction, x-ray emission and radiation transport, nonlocal thermodynamic equilibrium kinetics, and hydrodynamic mixing at the interface, etc. In our previous research [17][18][19], we applied the classical average atom (AA) model in the code but acquired some inaccurate results. For example, the simulated bubble size and the electron temperature (T e ) within the bubble are obviously overestimated compared to the experimental results.…”

Influence of laser-induced Au-plasma plume collision on the efficiency of x-ray radiations and the energy-transport process relevant to ICF

“…However, it is quite different in ICF physics that strong colliding processes occur more frequently. Especially, for the indirect-drive configuration where multi-laser beams are used to injected into a high-Z material hohlraum (gold or uranium) to provide an x-ray radiation source [37,39], plasma plumes from different focal spots of lasers will expand and collide with each other. There has been some previous work showing that bright x-ray radiations were produced during the plume colliding [37] It reveals that the local plasma evolution is complex and inhomogeneous in space.…”

Optimization of tungsten-doped high density carbon target in inertial confinement fusion

“…In recent years, depleted uranium (DU) hohlraum has been proposed to improve the hohlraum performance [8,9]. DU can enhance the total x-ray flux and reduce the preheat effect vs Au [10][11][12]. These two advantages have been proved in experiments, so DU may be a good choice.…”