Initial Experimental Results of indirectly-driven ICF implosions in the I-Raum*

A new advanced hohlraum concept, the I-Raum [1], has been experimentally tested on the NIF.  Initial results show enhanced inner beam propagation compared to a typical cylindrical hohlraum.  This enhanced propagation is achieved by recessing the location where the outer beam cones hit the hohlraum wall.  This target modification delays when the Au wall material, driven by the outer beam cones, obstructs the inner beam and reduces propagation.  X-ray images of the Au wall motion and measurements of the shape of the imploded capsule show improvements over the standard cylinder geometry.  Detailed hohlraum simulations are presented in a companion talk by Robey et al.

[1] H. F. Robey et al., “The I-Raum: A new shaped hohlraum for improved inner beam propagation in indirectly-driven ICF implosions on the National Ignition Facility”, Phys Plasmas 25, 012711 (2018).