Wire fixturing in high wire-number z pinches critical for high radiation power and reproducibility

The quality of high wire-number z-pinch implosions on Z using a dynamic hohlraum (DH) configuration [Sanford, et al., Phys. Plasmas 9, 3573 (2002)] is significantly affected by the method of holding the wires. The three arrangements discussed here have led to differences in radial and axial x-ray powers of factors of 1.6±0.2 and 1.5±0.2, respectively. An increase in power is accompanied by reductions in rise time and pulse width, and improvements in shot-to-shot reproducibility. Higher powers are produced by fixtures that enable the wires to be maintained taut, which also produce superior current contacts at the electrodes (and in particular at the cathode) prior to implosion. The increased axial power, and decreased variation in power and pulse shape, correlate with decreased wire-plasma material observed at the axial radiation exit holes of the DH.