Accurate Hugoniots and sound velocities of bismuth under shock compression in the 38-100 GPa range

Dynamic compression experiments of bismuth (Bi) in a shock pressure range of 38-100 GPa were conducted using an explosive drive. The time-resolved particle velocity profiles at the Bi/LiF (lithium fluoride) interface and the impact velocities were recorded with a displacement interferometer system for any reflector (DISAR). Shock velocities of Bi were measured based on the shorted-pin technique. Sound velocities of Bi were obtained from the peak state time duration measurements with the overtake method. Uncertainties in the measured Hugoniots and sound velocities were analyzed carefully. The new Hugoniot relation, Us = (1.666 ± 0.057) km/s + (1.596 ± 0.037)Up (1.13 km/s ≤Up≤2.05 km/s), was determined by fitting the measured shock velocity and particle velocity to a line. The relation between the Grüneisen coefficient and the density, γρ=const., is found to be a good approximation to describe the sound velocities of Bi above the shock-induced melting pressure, by carefully analysis of the sound velocity data.