The role of electron heat conductivity and radiation transport in 1D simulations of wire explosions in Zebra experiments

Experiments at the Zebra facility at the University of Nevada, Reno, have been conducted to study the behavior of thick metal wires at ultrahigh magnetic fields. Currents of about 1 MA with 100 ns rise time were passed through 0.5 mm to 2 mm diameter aluminum wires. A number of diagnostic techniques used in the experiments provided data on radial expansion of wires and radiation of dense plasma formed on their surface by electrical explosion. The experiments have demonstrated that wires remain rather uniform lengthwise and can therefore be simulated numerically using 1D simulations. This paper considers the influence of radiation and heat conductivity on plasma formation processes. The simulations have shown that both processes - electron heat conductivity and radiation transport - should absolutely necessarily be taken into account for adequate description of plasma formation and wire dynamics in the experiments. Along with this, processes of electron heat conductivity magnetizing in the low-density plasma region have a minor effect on plasma formation processes and profiles of different quantities, and can therefore be ignored. It is also shown that variation of radiation transport factors by an order of magnitude weakly affects simulation results; and one can therefore expect that 1D simulations can adequately describe the experiments despite the existing uncertainty in transport factors.