Effects of Pre-Ionization on Current Distribution in a Gas-Puff Z-Pinch

The Z-machine at Sandia National Laboratories is instrumental in plasma physics research across a range of applications. University-scale gas-puff z-pinch experiments at lower currents (~1-MA), can inform the higher-current (~20-MA) experiments conducted on the Z-machine. A gas-puff z-pinch puffs gas into the anode-cathode gap, which is then pulsed with a high voltage. The gas is ionized, accelerated, and compressed as the current flows across the electrodes, allowing for study of pinch phenomena including fusion reactions. The initial ionization or pre-ionization condition of the gas-puff prior to compression is poorly understood¹. The effects of pre-ionization on the current distribution through the gas-puff as the implosion progresses is also an open question. Quantifying how the pre-ionization and current distribution affect x-ray and fusion production, which are largely the result of micro-pinch instabilities, is crucial to understanding z-pinch physics. We report on the development of, and initial results from, the gas-puff experiment for the 1-MA, 100-ns MAIZE Linear Transformer Driver.

1. J. Giuliani, “A Review of the Gas-Puff Z-Pinch as an X-Ray and Neutron Source”, IEEE Trans. Plasma Sci. 43, 2385 (2015).