High-Z elements, such as silicon (Si), are usually doped in the outer ablator in direct-drive inertial confinement fusion (ICF) to smooth the laser non-uniformity^[1]. However, their specific effects on the implosion performance are not well understood. In this article, the direct-drive implosions of targets with varying Si doping ratios (0%, 6.25%, 12.5%) are studied through 2D radiation hydrodynamic simulations, in which the non-local electron transport is considered^[2-3]. As the doping ratio increases, the inward electron heat flux is reduced, while the radiation temperature is enhanced. This leads to a 4.5% and 35.2% increase in fuel temperature for the two doped targets. Besides, the maximum perturbation amplitude is also decreased by 26.1% and 47.7%.
Consequently, the hot spot pressure rises by 16.7% and 44.2%, and the areal density increases by 23.5% and 29.7%, respectively. These findings indicate that high-Z dopant can improve implosion performance through significant suppression of hydrodynamic instability, with the trade-off of enhanced preheating. Therefore, appropriately increasing the doping concentration may improve implosion performance. Above findings advance the understanding of high-Z dopant effects in direct-drive implosions and offer valuable insights for the design of ICF targets.

Inertial confinement fusion,,Direct-drive implosion,electron non-local transport,high-Z dopant