Optical investigation z-pinch wire array dynamics and X-ray/foil interactions

Summary form only given, as follows. The experimental results of the investigation of the radial dynamics of wire array z-pinches and the interaction of the pinch radiation with foil targets using streaked optical imaging with a laser backlighter and plasma self emission are presented. Experiments were performed on the Z accelerator at Sandia National Laboratories. A long pulse laser 532 nm wavelength, 1 kW power and /spl sim/10 /spl mu/s pulse duration was used to backlight the targets. We observe the timing of the initiation of wire ablation, acceleration of the wire array, vaporization of the current return can and line-of-sight closure. After surface breakdown, the wires ablate for a duration of 100 ns up to the maximum current. During this time, the wire array remains at its initial position. After a fast acceleration, the edge of the plasma shell moves with a velocity of 300-400 km/s, stagnating with a final velocity of /spl sim/800 km/s according to the X-ray self-emission streak. At nearly half of the maximum current, a plasma is created from the internal side of the can which expands with velocity /spl sim/10 km/s. After the peak X-ray radiation, the plasma from the can accelerates to a velocity of /spl sim/120 km/s. Experimental results are compared with 1D SCREAMER and ablative model codes. The interaction of X-ray radiation with a foil target placed outside the can was investigated by measuring the front and rear expansion velocity vs. the foil thickness and material. The X-ray power flux on the front side of the target was /spl sim/10/sup 14/ W/cm/sup 2/. The explosion of the foil demonstrates a slow expansion velocity during wire run-in, before the main X-ray burst and almost 10 times faster thereafter. The results of foil experiments have been simulated using a BUCKY 1D code.