Optimizing doping parameters of target to enhance direct-drive implosion

TL;DR

This paper presents an optimization procedure using particle swarm optimization to determine doping parameters in target materials, enhancing direct-drive implosion performance while reducing hydrodynamic instability risks in inertial confinement fusion.

Contribution

The study introduces a novel optimization framework combining 1D simulations and high-dimensional evaluations for doping parameters in inertial confinement fusion targets.

Findings

Doping with Si or Cl mitigates instability during acceleration.

The optimization maintains peak areal density with minimal degradation.

Results from 1D and 2D simulations are consistent, validating the method.

Abstract

Direct-drive is an important approach to achieving the ignition of inertial confinement fusion. To enhance implosion performance while keeping the risk of hydrodynamic instability at a low level, we have designed a procedure to optimize the parameters of the target doped with mid- or high-$Z$ atoms. In the procedure, a one-dimensional implosion can be automatically simulated, while its implosion performance and high-dimensional instability are integrally evaluated at the same time. To find the optimal doping parameters, the procedure is performed in the framework of global optimization algorithm, where we have used the particle swarm optimization in the current work. In the optimization, the opacity of mixture materials is quickly obtained by using an interpolation method, showing only a slight difference from the data of TOPS, which is an online doping program of Los Alamos National Laboratory. To test the procedure, optimization has been carried out for the CH ablator in the double cone ignition scheme [Phil. Trans. R. Soc. A. 378.2184 (2020)] by doping with Si and Cl. Both one- and two-dimensional simulations show that doping with either Si or Cl can efficiently mitigate the instability during the acceleration phase and does not result in significant degradation of the peak areal density. The results from one- and two-dimensional simulations qualitatively match with each other, demonstrating the validity of our optimization procedure.