Effect of surface roughness on phase transition timing in pulsed-power–driven exploding conductors

What is it about?

This study analyzes phase transitions in electrical conductor explosions using resistive magnetohydrodynamic simulations to show that micrometer-scale surface roughness can lead to the electrothermal instability (ETI), a feedback effect that concentrates resistive heating and leads to early melting and ablation. This study shows 1D simulations are adequate to model conductors with sub-micrometer-scale surface roughness in this high-energy-density regime; however, 2D or 3D simulations are required to capture the full range of physics for accurately describing phase transitions in conductors with micrometer-scale or larger surface roughness.

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Photo by Hal Gatewood on Unsplash

Photo by Hal Gatewood on Unsplash

Why is it important?

An understanding of material phase transitions in megaampere pulsed-power–driven exploding conductors is important for predicting the growth of hydrodynamic instabilities, which are the principal cause of yield degradation for pulsed-power–driven magneto-inertial fusion (MIF) concepts, such as magnetized liner inertial fusion (MagLIF). A better understanding of how surface roughness evolves into these hydrodynamic instabilities would allow for better predictions of fuel-liner mixing and temperature distributions in MIF.