Using pulsed power for hydrodynamic code validation

As part of ongoing hydrodynamic code validation efforts, a series of Near Term Liner Experiments (NTLX) was designed for the Shiva Star capacitor bank at the Air Force Research Laboratory (AFRL). A cylindrical aluminum liner that is magnetically imploded onto a central target by self-induced radial Lorentz forces drove the experiments. The behavior of the target was simulated using the adaptive mesh refinement (AMR) Eulerian hydrodynamics code RAGE in 2- and 3-D. One-dimensional simulations of the liner driver utilizing the RAVEN MHD code were used to predict the liner density and temperature profiles as well as the velocity at impact time. At liner/target impact, a convergent shock is generated that drives subsequent hydrodynamics experiments. In concentric targets, cylindrically symmetric shocks will converge on axis. This characterizes the symmetry of the liner driver. By shifting the target center away from the liner symmetry axis, material dependencies in the shock propagation velocity generate off-center shock convergence. Both codes show excellent agreement over the majority of the shock and interface trajectories. However, a small but significant discrepancy between codes does occur during the last few millimeters of run in when convergence effects are greatest. Comparisons with experimental data show similar shock velocities being measured. However, the simulated shock arrives at a given trajectory location nearly 100 ns earlier than experimentally measured.