High ρR Mo-doped Be heavy ablator for high yield: Experimental design and implosion physics

Beryllium ablators with inner layer doped with increasing Mo concentration towards the center can increase ρR and the burn fraction. The mass of this type of “heavy ablator” is >30% than conventional ablators with same radius. Implosion simulations of heavy ablators with acceptable RTI and high yield were reported.¹ Based on this, implosion experiments with capsule radius of 1175 µm using 1.7 MJ of laser energy is designed. The ratio of the high-mode 2D simulated yield to the 1D simulated yield using the heavy ablator is lower than that of the HDC N210207 shot that gives record neutron yield close to 6e16 using 1.93 MJ of laser energy. However, the simulated 2D yield of the heavy ablator design is still higher than either the N210207 simulated or measured yield. The 2D/1D yield ratio for the heavy ablator is lower because high-ρR implosions in general have a steeper ignition cliff. The implosion moves away from the cliff if the laser energy is increased to 1.87 MJ, which boosts the 2D simulated yield to multi-MJ range.