Experimental studies of material strength of metals with artificially implanted helium bubbles in the high energy density regime*

Plasma-driven ramp compression is a powerful means of studying materials at high-pressure conditions without melting. Understanding plastic deformation dynamics of materials under extreme conditions is of high interest to a number of fields, including meteor impact dynamics and advanced inertial confinement fusion. We infer the strength of samples at pressures up to 8 Mbar, strain rates of ~10⁷ s^-1, and high strains > 30% by measuring the growth of Rayleigh-Taylor instabilities (RTI) under ramped compression. We are now studying the dynamic response of materials that are aged by the radioactive alpha decay process. We fabricated lead samples that were artificially implanted with helium bubbles to mimic the effects of alpha decay. We conducted side-by-side comparisons of pure versus helium-doped lead samples using the NIF laser facility. Initial results from these experiments will be presented.