  Collisional plasma shocks generated from supersonic flows are an important
feature in many astrophysical and laboratory high-energy-density plasmas.
Compared to single-ion-species plasma shocks, plasma shock fronts with multiple
ion species contain additional structure, including interspecies ion separation
driven by gradients in species concentration, temperature, pressure, and
electric potential. We present time-resolved density and temperature
measurements of two ion species in collisional plasma shocks produced by
head-on merging of supersonic plasma jets, allowing determination of the ion
diffusion coefficients. Our results provide the first experimental validation
of the fundamental inter-ion-species transport theory. The temperature
separation, a higher-order effect reported here, is valuable for advancements
in modeling HED and ICF experiments.
