The role of a detailed configuration accounting (DCA) atomic physics package in explaining the energy balance in ignition-scale hohlraums

Analysis of the National Ignition Facility ignition hohlraum energetics experiments

“…In particular the inclusion of dielectric recombination allows the re-population of active levels which enables more efficient radiation. The second improvement increases the flux limiter to f = 0.15 that better matches the temperature distribution of more sophisticated non-local electron transport models (see ref [12] for a comparison of the non-local electron transport model to various flux-limiters).…”

“…We have recently developed a new model for hohlraums called the high flux (HF) model that incorporates two physics improvements [11,12]. The first improvement is to the atomic physics model of the hohlraum wall.…”

“…The ratio between the energy stored in the corona to the wall loss thus scales as ratio of the hohlraum volume to the area which is proportional to the hohlraum scale size. A more emissive atomic physics model reduces the energy stored in the coronal plasma, which is more significant at NIF scale where up to 40% of the energy is stored in the corona as opposed to 20% at OMEGA scale [12,13]. With the advent of faster computers it has become possible to routinely run NLTE atomic physics models based on the detailed configuration accounting (DCA) approach [15] that include many thousands of levels compared to the tens of levels used in average atom models such as XSN.…”

Towards an integrated model of the NIC layered implosions

“…The 2-D integrated (hohlraum + capsule) simulations described in this paper use the "high-flux model"-electron thermal conduction with a flux-limiter f = 0.15 and the DCA non-LTE atomic physics model [6]. The hohlraum wall opacity is obtained from LTE tables (calculated offline using separate codes) for temperatures below 300 eV.…”

Some recent studies on hohlraum physics

“…Hohlraum plays a key role in the study of indirect drive inertial fusion [1,2], and worldwide IFE (Inertial Fusion Energy) scientists have been paying many efforts in the study of hohlraum physics [3,4]. Here, we will present some of our recent studies on hohlraum energetic and hohlraum design, including studies on recent hohlraum physics experiments on SGIII prototype [5], Au + U + Au sandwich hohlraum for ignition target [6], and method of giving an initial design of hohlraum and driving laser to generate a required radiation for 2-D optimizations [7].…”