Explosive electrical wire failures behave differently depending on the voltage applied

Studying the electrical explosion of wires (EEW) has wide-ranging applications from fusion to X-ray generation. The process occurs on a spectrum of time and length scales, depending on the energy applied to the system. Using high-speed imaging, Sechrest et al. imaged the breakup of electrical wires during explosion and found three distinct regions of behavior.

For low deposited energies, the group observed a fluid instability of the liquid metal column. On the other hand, at much higher energies, the wire transitions into a rapidly expanding cloud of small liquid droplets and vapor. In between these two extremes, the wire initially remains unchanged before being violently torn apart by bubble-like instabilities, causing it to quickly expand and disintegrate.

“The evolution of these instabilities is intricate and quite beautiful,” said author Yancey Sechrest.

Videos of these explosive wire failures were taken at 300,000 frames per second, allowing for the observation of the multiscale dynamics. To understand all three energy deposition regions, the authors varied the applied voltage.

They view this as a steppingstone to studying EEWs with more advanced imaging techniques, allowing for their use in predictive science and for manufacturing light sources, detonators, nanoparticles and nanopowders.

“EEW is a fascinating subject for high-speed imaging and predictive science, because it is a deceptively simple experiment that generates a fast stochastic process involving almost all phases of matter,” Sechrest said. “We believe that studying events like EEW with various high-speed imaging modalities is one path to better understanding the behavior of materials under extreme conditions, such as the cores of planets or even stars and other astrophysical explosions.”

Source: “High-speed imaging of transition from fluid breakup to phase explosion in electric explosion of tungsten wires in air,” by Y. Sechrest, C. Campbell, X. Tang, D. Staack, and Z. Wang, Applied Physics Letters (2020). The article can be accessed at https://doi.org/10.1063/5.0019211 .