A fast ignition isochoric direct drive compression design with a 527 nm wavelength

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.