Radiative shocks in strongly coupled plasmas on the Omega-60 laser*

Compact objects exist in some of the most extreme conditions of temperature and density in the universe. Neutron stars, an example of a compact object, are quite difficult to observe due to their small size and birth within clouds of gas after supernova explosions. Neutron star envelopes exist as a strongly coupled plasma of predominantly iron. These extreme conditions stress models of radiation hydrodynamics and radiation transport because it breaks the assumptions of weakly coupled plasma theory. The work presented here shows simulation and preliminary results from experiments at the Omega-60 laser at the Laboratory for Laser Energetics to study radiative shocks in strongly coupled plasmas at temperature and density conditions relevant to neutron star envelopes. These experiments use a capsule implosion with a 7 μm plastic layer and a layer of mid-Z metal on the interior surface. The capsule mass is constant through varying the metal layer thicknesses for different materials and different metals have different nuclear charges, which vary the ion coupling parameter as Z². Filtered x-ray framing camera measurements observe the K-shell emission of the metal layer and track the velocity of the inflowing plasma and rebounding shock. X-ray spectroscopy measurements provide information on the ionization states present and the effects of radiation transport in the system.