Laser propagation in simulations of low fill density hohlraums

We present analysis of laser propagation in simulations of low fill density hohlraums on the National Ignition Facility (NIF). Simulations using the radiation hydrodynamic code \textsc{hydra} are compared in 2D and 3D. The absorption of laser rays in different materials and spatial locations is extracted from the simulations to identify where and when the inner cone laser beams undergo significant absorption. Inner cone laser beams can be absorbed in the outer cone ``gold bubble'' or in the region where the ablator and hohlraum material interact. The simulations provide guidance on which hohlraum mitigation methods will be most effective at improving inner beam propagation.