Mixing of plastic ablator material, doped with Cu and Ge dopants, deep into the hot spot of ignition-scale inertial confinement fusion implosions by hydrodynamic instabilities is diagnosed with x-ray spectroscopy on the National Ignition Facility. The amount of hot-spot mix mass is determined from the absolute brightness of the emergent Cu and Ge $K$-shell emission. The Cu and Ge dopants placed at different radial locations in the plastic ablator show the ablation-front hydrodynamic instability is primarily responsible for hot-spot mix. Low neutron yields and hot-spot mix mass between $34(-13,+50)\mathrm{ng}$ and $4000(-2970,+17160)\mathrm{ng}$ are observed.

• Received 23 November 2011

DOI:https://doi.org/10.1103/PhysRevLett.111.045001