A 1D simulation design study for fast ignition implosions using the second harmonic of a Nd:glass laser (527 nm) is presented. Designs are obtained by combining particle swarm optimization Kennedy and Eberhart, Proceedings of International Conference on Neural Networks (ICNN'95), Perth, WA, Australia (IEEE, 1995), Vol. 4, pp. 1942–1948 with radiation hydrodynamic simulations using the code MULTI-IFE Ramis and Meyer-ter-Vehn, Comput. Phys. Commun. 203, 226 (2016). Considerations of limits like the maximum laser intensity, the laser power contrast, and the central gas density are incorporated into the design iterations. A subset of the simulation results is verified with the code DUED Atzeni et al., Comput. Phys. Commun. 169, 153 (2005). The obtained design features a low absorption of the incident laser because outer parts of the beam are being refracted around the imploding shell which lowers the absorption. A single stage of laser beam zooming substantially increases the absorption while decreasing the laser power contrast, the compression energy, and the incident intensity. A comparison to compression designs in literature is drawn, which reveals the efficiency of the described approach.
Brönner et al. (Fri,) studied this question.