Imaging velocity interferometer system for any reflector (VISAR) diagnostics for high energy density sciences

Abstract

Two variants of optical imaging velocimetry, specifically the one-dimensional streaked line-imaging and the two-dimensional time-resolved area-imaging versions of the Velocity Interferometer System for Any Reflector (VISAR), have become important diagnostics in high energy density sciences, including inertial confinement fusion and dynamic compression of condensed matter. Here, we give a brief review of the historical development of these techniques, then describe the current implementations at major high energy density (HED) facilities worldwide, including the OMEGA Laser Facility and the National Ignition Facility. We illustrate the versatility and power of these techniques by reviewing diverse applications of imaging VISARs for gas-gun and laser-driven dynamic compression experiments for materials science, shock physics, condensed matter physics, chemical physics, plasma physics, planetary science and astronomy, as well as a broad range of HED experiments and laser-driven inertial confinement fusion research.

B1-B2 transition in shock-compressed MgO

“…XRD ( 21 ) was used to measure the crystal structure and density of MgO. Peak stress of the MgO was constrained using Doppler velocimetry [VISAR, ( 22 )], which monitored the shock-front velocity and reflectivity in a quartz window.…”

Technology and times scales in Photonic Doppler Velocimetry (PDV)

“…Line [41] and area [42] imaging are a domain where VISAR retains some advantage over PDV. Rather than using discrete detectors, these diagnostics image a sample line onto a streak camera or a sample area onto a framing camera, providing spatially-resolved velocity measurements.…”