A preliminary assessment of the sensitivity of uniaxially-driven fusion targets to flux-limited thermal conduction modeling

TL;DR

This study investigates how different models of flux-limited thermal conduction affect the performance predictions of uniaxially-driven fusion targets, highlighting the importance of ionic heat flow modeling and uncertainties in plasma microphysics.

Contribution

It provides a preliminary assessment of the impact of conduction modeling choices on fusion target performance, emphasizing ionic transport and microphysics uncertainties.

Findings

Ionic heat flow modeling significantly influences target performance predictions.

Electronic conduction is consistently well-described by local diffusion models.

Simulations did not replicate previously reported neutron yields, indicating the need for further research.

Abstract

The role of flux-limited thermal conduction on the fusion performance of the uniaxially-driven targets studied by Derentowicz et al.; Jour. Tech. Phys. 18, 465 (1977) and Jour. Tech. Phys. 25, 135 (1977), is explored as part of a wider effort to understand and quantify uncertainties in ICF systems sharing similarities with First Light Fusion's projectile-driven concept. We examine the role of uncertainties in plasma microphysics and different choices for the numerical implementation of the conduction operator on simple metrics encapsulating the target performance. The results indicate that choices which affect the description of ionic heat flow between the heated fusion fuel and the gold anvil used to contain it are the most important. The electronic contribution is found to be robustly described by local diffusion. The sensitivities found suggest a prevalent role for quasi-nonlocal ionic transport, especially in the treatment of conduction across material interfaces with strong gradients in temperature and conductivity. We note that none of the simulations produce neutron yields which substantiate those reported by Derentowicz et al. Jour. Tech. Phys. 25, 135 (1977), leaving open future studies aimed at more fully understanding this class of ICF systems.