An Experiment to Observe Photoionization Fronts in the Laboratory

An experiment at the Omega-60 laser investigates radiation front propagation in a regime where the radiation transport is non-diffusive yet the initial target is many mean free paths in extent. The atomic physics at the front is such that photoionization is the dominant heating mechanism there. This type of front is relevant to star-forming regions and the age of reionization of the universe. In the experiment, a thin Au foil irradiated with a laser energy flux of ~10^14 W/cm^2, creates soft x-rays source that are incident on a N gas cell. The N is doped 1% Ar to enable absorption spectroscopy measurements. We will show preliminary results from upcoming experiments.