Generation of a 400 GPa pressure in water using converging strong shock waves

Results related to the generation of an extreme state of water with pressure up to (4.3 ± 0.2)·1011 Pa, density up to 4.2 ± 0.1 g/cm3, and temperature up to 2.2 ± 0.1 eV in the vicinity of the implosion axis of a converging strong shock wave are reported. The shock wave was produced by the underwater electrical explosion of a cylindrical Cu wire array. A ∼8 kJ pulse generator with a current amplitude ≤550 kA and rise time of 350 ns was used to explode arrays having varying lengths, radii, and number of wires. Hydrodynamic numerical simulations coupled to the experimental data of the shock wave propagation in water, rate of energy deposition into the array, and light emission from the compressed water in the vicinity of the implosion axis were used to determine the pressure, density, and temperature profiles during the implosion. Results of a comparison between these parameters obtained with the SESAME and quantum molecular dynamics data bases of equation of state for water are reported as well. Also, the dependences of the maximal pressure in the vicinity of the implosion axes on the array radius and the deposited energy density per unit length are reported.