Investigation of the performance of mid-Z Hohlraum wall liners for producing x-ray drive

M-band transitions (n = 4 → 3) in gold are responsible for a population of x-rays with energy >1.8 keV in indirect drive inertial fusion. These x-rays can preheat the fuel, cause the ablator–fuel interface to become unstable to Rayleigh–Taylor instabilities, and introduce radiation nonuniformity to the x-ray drive. This work investigates the performance of mid-Z lined Hohlraums for producing an efficient drive spectrum absent of M-band x-rays using the two-dimensional Lagrangian radiation hydrodynamics code h2d. The removal of the M-band transitions is observed in the Cu-lined Hohlraum reducing the total x-ray energy above 1.8 keV to 58% that of the un-lined Hohlraum. Total radiation energy in the Cu-lined Hohlraum is 93% that of the energy in the pure Au Hohlraum for a 1 ns pulse. However, the soft x-ray drive energy (below 1.8 keV) for the lined Hohlraum is 98% that of the pure Au Hohlraum.