Physics of one-dimensional capsule designs for the National Ignition Facility

This article describes a suite of 250, 280, and 350 eV copper-doped Be [Be(Cu)] capsule designs for the National Ignition Facility [Paisner et al., Laser Focus World 30, 75 (1994)] and compare these to previous Be(Cu) and bromine-doped CH plastic [CH(Br)] capsule designs for 300 and 330 eV drives. These capsule designs are constrained to have the same deuterium-tritium (DT) fuel mass as the 300 and 330 eV designs so that differences in yield are due to differences in capsule compression before ignition. The one-dimensional (1-D) calculations show that the fuel ρr reaches a maximum value when about 20–30 μm of ablator material is left behind, and this amount of ablator material provides the best trade-off between maximizing the fuel ρr, the implosion velocity, and the calculated clean yield. The results of this paper add optimized 1-D capsule designs that operate at drive temperatures of 250, 280, and 350 eV and they complement the established 300 eV CH(Br) ablator and the 330 eV Be(Cu) ablator designs.