Laser-based imaging of wire array z-pinches and X pinches on the COBRA pulsed power generator*

Initial laser-based imaging experiments of wire array z-pinches and X pinches on the 1 MA COBRA pulsed power generator are presented. The imaging system makes use of a frequency-doubled 532 nm green beam from a Nd:YAG laser source. This source also supplies the frequency-quadrupled 266 nm UV beam that is used to trigger the final output switches of the COBRA generator and initiate a current pulse. Thus, the desired timing of the imaging beam relative to the start of a current pulse is achieved by adjusting the optical path length of the imaging beam. Once the imaging beam has passed through the pinch region, the light is collected on a high resolution CCD camera that is linked to a PC for fast image processing. The laser-based images produced, along with images and measurements from other supporting diagnostics, are presented.