Experimental and Numerical Investigation of Shock-Wave Generation in Water by Electrical Wire Explosions*

Electrical wire explosions (EWEs) are performed in water using a 26-kilovolt pulsed power generator (PPG) to generate extreme fluid conditions. Kiloamp currents are discharged through a thin copper wire, causing it to rapidly transition from a solid into an expanding plasma which produces a cylindrical shock wave. Using voltage-current time traces and high-speed imaging, the system's performance is characterized by conducting EWEs with different μm-diameter wires and initial energies. Calculation of the transferred electrical energy and initial mechanical energy of the shock waves indicates gigawatt-level power delivery, shock pressures in the hundreds of MPa, and Mach numbers up to 1.8. The experimental results are compared to numerical simulations which couple a 0-D magnetohydrodynamic model for the wire expansion, a 1-D Euler model for the shock wave propagation, and an RLC circuit model for the PPG. These simulations implement SESAME tables to evaluate the equations of state for copper and water. The comparison between experiments and simulations provides insight into the simulations' ability to capture the multiscale physics of shock generation through EWEs.