A Dual Laser-Beam Configuration Compatible with Both Symmetric Direct Drive and Spherical Hohlraums

This work continues to investigate the feasibility of laser-beam configurations that would make possible both spherical direct drive and spherical indirect drive on the same ignition-scale laser system, exploring, in particular, the port arrangement proposed in Ref. [1]. This geometry permits the use of octahedral hohlraums (with six laser entrance holes based on the faces of a cube), proposed by Lan et al.,[2] which offer excellent uniformity without the need for different pulse shapes in different beams. The trade-off between uniformity and radiation temperature is examined in designs with different case-to-capsule ratios. For direct drive, the beams require a small amount of repointing (much less than is typical for direct-drive designs on the National Ignition Facility). The sensitivity of uniformity to the laser pointing and spatial profile is investigated. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0003856.

 

[1] R. S. Craxton et al., Bull. Am. Phys. Soc. 64, GO09.00001 (2020).

[2] K. Lan et al., Phys. Plasmas 21, 010704 (2014).