Impact of first-principles properties of deuterium–tritium on inertial confinement fusion target designs

Abstract

A comprehensive knowledge of the properties of high-energy-density plasmas is crucial to understanding and designing low-adiabat, inertial confinement fusion (ICF) implosions through hydrodynamic simulations. Warm-dense-matter (WDM) conditions are routinely accessed by low-adiabat ICF implosions, in which strong coupling and electron degeneracy often play an important role in determining the properties of warm dense plasmas. The WDM properties of deuterium–tritium (DT) mixtures and ablator materials, such as the equation of state, thermal conductivity, opacity, and stopping power, were usually estimated by models in hydro-codes used for ICF simulations. In these models, many-body and quantum effects were only approximately taken into account in the WMD regime. Moreover, the self-consistency among these models was often missing. To examine the accuracy of these models, we have systematically calculated the static, transport, and optical properties of warm dense DT plasmas, using first-principles (FP) methods over a wide range of densities and temperatures that cover the ICF “path” to ignition. These FP methods include the path-integral Monte Carlo (PIMC) and quantum-molecular dynamics (QMD) simulations, which treat electrons with many-body quantum theory. The first-principles equation-of-state table, thermal conductivities (κQMD), and first principles opacity table of DT have been self-consistently derived from the combined PIMC and QMD calculations. They have been compared with the typical models, and their effects to ICF simulations have been separately examined in previous publications. In this paper, we focus on their combined effects to ICF implosions through hydro-simulations using these FP-based properties of DT in comparison with the usual model simulations. We found that the predictions of ICF neutron yield could change by up to a factor of ∼2.5; the lower the adiabat of DT capsules, the more variations in hydro-simulations. The FP-based properties of DT are essential for designing ICF ignition targets. Future work on first-principles studies of ICF ablator materials is also discussed.

Fully consistent density functional theory determination of the insulator-metal transition boundary in warm dense hydrogen

“…An essential prerequisite for quantitative modeling of all such planetary phenomena is an accurate equation of state (EOS) that includes the IMT correctly [4]. Furthermore, and independently of planetary physics, an accurate EOS for H and its isotopes also is essential for progress in inertial confinement fusion and high-energy-density physics research [5].…”

Deep energy-pressure regression for a thermodynamically consistent EOS model

“…Modeling the EOS table is an important task in high-density-energy computational physics. Having a reliable EOS table that covers a wide range is often difficult because of the shortcomings of various computational models [11,12] and the discrepancies among these methods in the overlapping range [7][8][9]. iFPEOS provides a more accurate model that covers a wide range of density and temperature values [7].…”

“…Recently, an improved version of the first-principles EOS table (iFPEOS) for deuterium is published [7], which is an update on FPEOS [8,9] based improved theoretical methods such as ab initio molecular dynamics (AIMD). These methods are driven by density functional theory (DFT), where advanced meta-generalized gradient approximation (meta-GGA) exchange-correlation (XC) free energy density functional TSCANL [10], a high-accuracy non-interacting orbital-free free energy density functional LKTFγTF (see details in [7]) is used.…”

A Kinetic Model for Electron-Ion Transport in Warm Dense Matter

“…The microscopic physics of WDM is subject to a multitude of physical effects, including electron degeneracy, partial ionization, large-angle scattering, diffraction, and moderate Coulomb coupling leading to correlations. Such conditions are present in experiments involving extreme compression of materials [1][2][3], in astrophysics [4,5], and along the compression path in inertial confinement fusion (ICF) experiments [6]. As a result of the demanding conditions for theoretical modeling, the description of WDM has been highly reliant on computational techniques.…”