Thesis (Ph. D.)--University of Rochester. Department of Physics and Astronomy, 2017.
The behavior of carbon at terapascal pressures (10’s of millions of atmospheres) is
important to modeling ice giant planets and white dwarf stars and to designing inertial confinement
fusion (ICF) experiments, where diamond is used to contain and compress the
hydrogen fuel. The high-pressure shock and release responses of diamond are of particular
interest to the initial stages of an ICF implosion. Measurements of these behaviors provide
rigorous constraints on important paths through carbon’s equation of state. This work
presents experimental Hugoniot and release data for both single-crystal diamond (SCD) and
nanocrystalline diamond (NCD), which is comprised of nanometer-scale diamond grains
and is 5% less dense than SCD. We find that the NCD used in ICF experiments has a
stiffer Hugoniot than SCD that can be attributed to porosity. A Gr¨uneisen parameter of 1
for high-pressure fluid carbon was derived from the NCD and SCD Hugoniots and is used
in Mie-Gr¨uneisen models to accurately describe the NCD and SCD release data.
