Simultaneous Constraint of Pressure, Temperature, and Density in a Gigabar Plasma*

Laser-driven implosion experiments leverage convergent geometry to assemble matter to some of the most extreme conditions accessible in the laboratory. For this reason, implosions offer a compelling platform to further our understanding of materials at pressures relevant to stellar interiors, fusion plasmas, and the conditions of the early universe. In this work, we present the results of shock-dominated implosions of 3-µm-thick SiO₂ shells on the OMEGA-60 laser system at the Laboratory for Laser Energetics. In these experiments, a laser-driven, converging shock rebounds off the center of the target and interacts with the surrounding SiO₂, forming an expanding shell of hot, strongly-emitting plasma. Through detailed measurement and integrated analysis of the emitted radiation, we are able to simultaneously constrain the pressure, temperature, and density of the shocked SiO₂ at pressures exceeding 1 Gbar. The results are compared to equation of state models for SiO₂ at these conditions.