FLAIM: A reduced volume ignition model for the compression and thermonuclear burn of spherical fuel capsules

TL;DR

FLAIM is a modular, reduced-volume ignition model for spherical fuel capsules that balances computational efficiency with physical accuracy, enabling detailed analysis of implosion and burn processes in inertial confinement fusion.

Contribution

The paper introduces FLAIM, a new reduced model with a 1D hydrodynamics approach that improves accuracy over simple models while maintaining efficiency.

Findings

FLAIM closely matches 1D rad-hydro simulations across various parameters.

Accurate hydrodynamics treatment is crucial for modeling ignition.

Residual discrepancies are mainly due to heat losses.

Abstract

We present the "First Light Advanced Ignition Model" (FLAIM), a reduced model for the implosion, adiabatic compression, volume ignition and thermonuclear burn of a spherical DT fuel capsule utilising a high-Z metal pusher. FLAIM is characterised by a highly modular structure, which makes it an appropriate tool for optimisations, sensitivity analyses and parameter scans. One of the key features of the code is the 1D description of the hydrodynamic operator, which has a minor impact on the computational efficiency, but allows us to gain a major advantage in terms of physical accuracy. We demonstrate that a more accurate treatment of the hydrodynamics plays a primary role in closing most of the gap between a simple model and a general 1D rad-hydro code, and that only a residual part of the discrepancy is attributable to the heat losses. We present a detailed quantitative comparison between FLAIM and 1D rad-hydro simulations, showing good agreement over a large parameter space in terms of temporal profiles of key physical quantities, ignition maps and typical burn metrics.