Laboratory Generated Photoionization Fronts Relevant to Cosmology

Photoionization Fronts (commonly referred to as Ionization Fronts or PI fronts) are a type of radiation-driven heat front that dictate important physics in reionization era of the early universe. The first galaxies of the reionization era merged to form minihalos. Subsequently, these minihalos emitted ionizing radiation to the surrounding gas clouds, which generated PI fronts. The propagation and attenuation of a PI front within a gas cloud is an active area of study in early universe cosmology. In the laboratory setting, the Z Astrophysical Plasma Properties (ZAPP) platform on Sandia’s Z-Machine facility can generate an intense radiation source to drive a PI front through a 0.75atm nitrogen gas cell. To initially characterize the PI fronts, the speed and electron temperature of the PI front will be measured using photon-doppler velocimetry and streaked visible spectroscopy respectively. This work presents an initial experimental design accompanied by HELIOS radiation-hydrodynamic simulations, and PrismSPECT atomic kinetics calculations to better understand upcoming ZAPP experiments on Sandia’s Z-Machine.