Flow Visualization in High-Energy-Density Laboratory Plasmas

Flow visualization is often beneficial for enhancing the design of high-energy-density (HED) systems. Yet despite substantial advancements in HED science in recent years, the measurement of complex hydrodynamic flows at fine phenomenological scales, particularly above 1 Mbar (10¹¹ Pa), remains challenging. Progress in this area has not been limited by the ability to create the necessary high-pressure conditions, but by the limitations in spatial and temporal resolutions of contemporary x-ray imaging techniques. This talk introduces a diffractive x-ray imaging system designed to work in HED environments, utilizing multiple frames and integrating a Fresnel zone plate with a gated hybrid complementary metal-oxide semiconductor sensor. The purpose of this development is to enhance the exploration of advanced radiation-hydrodynamic phenomena, offering new possibilities to investigate the fundamental principles underlying multidimensional radiation-hydrodynamic simulations. Our measurements, with micron-scale resolution, demonstrate remarkable clarity in a wide range of material responses observed in high-Mach-number flows generated by the University of Rochester’s OMEGA laser. These include unstable interface dynamics, intense vorticity structures, microjetting events, and the exhausting of plasma from shock-driven cylindrical cavities in solid materials. A detailed overview of this approach to flow visualization will be presented, along with its utilization for the enhanced visualization of blast-induced instabilities and plasma jet formation in the context of empirical data, theoretical frameworks, and computational simulations. The significance of this research for an improved visualization of fine-scale flow features, such as those found in HED physics, inertial confinement fusion, and laboratory astrophysics research, will be emphasized.