Scaling of pulsed power produced convergent shockwaves in dielectrics – kA to multi-MA

The pulsed power driven explosion of cylindrical arrays of wires in water has been used for the past decade to produce high speed, convergent shockwaves. On axis, the pressures that these shockwaves are expected to produce, in the multi-Mbar regime, should result in warm dense matter conditions being created, even with relatively small pulsed power drivers.



Previously most experimental research has utilised currents from ~100-500kA, but this has recently expanded to include 2.5MA drives at one extreme, and as low as 30kA at the other. Coupled with either high resolution laser backlighting or the incredible multi-frame radiography capabilities of a 3^rd generation synchrotron, we are now able to explore how the wire explosion technique scales with current, risetime and insulator material. Furthermore, new experiments have enabled the first imaging (by radiography) of the shockwaves created in spherical implosion geometries.



Now investigations are being extended to the M3 generator at First Light Fusion. Here a peak current of ~8MA with a risetime of 2us enables extremely large arrays of wires or foils, 40mm diameter x 100mm long, to be fielded and instead of water solid plastic or silicone insulation is employed. Initial measurements of shock wave dynamics will compared to simulation, and methods to focus the shockwaves into external targets discussed.