Ionization states of carbon ions from shock compressed CH foams measured with X-ray Thomson scattering at the National Ignition Facility

Accurate equation of state (EOS) measurements in the warm dense matter (WDM) regime are extremely difficult to achieve due to the small volumes and short lifetimes of the systems typically created in laboratory experiments. Temperatures and ionization states are particularly challenging quantities to measure accurately in the WDM regime, yet they significantly affect the properties of matter at extreme conditions. High precision temperature measurements at these conditions are needed to improve EOS models used in inertial confinement fusion simulations and the modeling of planetary interiors. Here we will present the recently developed the Colliding Planar Shocks (CPS) platform on the NIF with the goal of creating large volumes of highly compressed matter with minimal spatial gradients to make high precision measurements of materials under extreme conditions. State variables such as the electron temperatures, electron densities, and ionization states can be extracted using simultaneous X-ray Thomson scattering (XRTS) and X-ray radiography. Initial experiments using the CPS platform have recently demonstrated the ability to compress solid CH and CH foams 3–8 times solid densities, as well as reach electron temperatures between 10-50 eV, and material pressures of 10–100 Mbar.