Measurements of the mass distribution and instability growth for wire-array Z-pinch implosions driven by 14-20 MA

The mass distribution and axial instability growth of wire-array Z-pinch implosions driven by 14-20 MA has been studied using high-resolution, monochromatic x-ray backlighting diagnostics. A delayed implosion is consistently observed in which persistent, dense wire cores continuously ablate plasma until they dissipate and the main implosion begins. In arrays with small interwire gaps, azimuthally correlated axial instabilities appear during the wire ablation stage and subsequently seed the early growth of magneto-Rayleigh-Taylor instabilities. The instabilities create a distributed implosion front with trailing mass that may limit the peak radiation power. (c) 2005 American Institute of Physics.