Shock compression of liquid argon, nitrogen, and oxygen to 90 GPa (900 kbar)

Abstract

Dynamic equation‐of‐state data for liquid Ar, N₂, and O₂ were measured in the shock pressure range 21–91 GPa (210–910 kbar) by means of a two‐stage light‐gas gun. The liquids were shocked from initial states near their saturation curves at 0.1 MPa (1 bar) and 80 K. The cryogenic target system is described. The initial liquid densities were obtained by measuring the temperature and pressure of the specimens and calculating the densities from published equations of state. Shock velocities were measured to 0.5–1.1% accuracy with an electronic detection system with subnanosecond time resolution. Impactor velocities in the range 4–7 km/s were measured to 0.1% accuracy with a flash radiographic technique. Mass velocities were obtained by the method of shock impedance matching. The data are discussed in terms of the statistical–mechanical theories of Ross and Ree.