Particle swarm optimization of 1D isochoric compression designs for fast ignition

A method to study isochoric compression to mass densities relevant for direct-drive fast ignition schemes is presented. The method is based on the combination of one-dimensional radiation-hydrodynamic simulations using the code MULTI-IFE [Ramis and Meyer-ter Vehn, Comput. Phys. Commun. 203, 226 (2016)] and a particle swarm optimization technique [Kennedy and Eberhart, in Proceedings of ICNN'95 - International Conference on Neural Networks (IEEE, Perth, WA, Australia, 1995), Vol. 4, pp. 1942–1948]. The compression of the fuel is optimized through variations of the incident temporal laser power profiles. Uniform mass density profiles are achieved by using appropriate objective functions that allow comparisons between the fuel assemblies obtained from simulations. Several objective functions were created and evaluated on their merits to yield isochoric compression assembly. Ultimately, such a profile is presented in conjunction with the technique to achieve it. A useful objective function is calculating the deviation of the simulated mass density profile from the ideal uniform mass density profile over a volume of the compressed target up to the radial position of the outgoing shock wave.