The impact of ablator-fuel mixing in ignition-class ICF implosions on NIF

ICF implosion experiments on NIF that attempted to repeat the 1.3 MJ experiment from August 2021 have underperformed and sometimes observed increased levels of ablator material mixing with the DT. Capsules are hydrodynamically unstable at many interfaces (hot-spot/fuel, fuel/ablator, undoped/doped-ablator, and ablation front), and these can degrade the implosion in different ways. Through 1D and 2D radiation-hydrodynamics models, we show how these different sources of mixing can degrade performance and their expected experimental signatures. In comparison with the data, this allows us to identify the origin of this mix, which can help focus mitigation efforts. We also discuss how this design can be made more robust to these different instability types.