2D Magnetohydrodynamic Simulations of the Electrothermal Instability in Metallic Liners

The Lawrence Livermore National Laboratory (LLNL) code Ares is used to study the electrothermal instability (ETI) - a resistive magnetohydrodynamic (MHD) instability that occurs due to a material’s resistivity being temperature- and density-dependent. The ETI often seeds other MHD instabilities like the magneto-Rayleigh-Taylor instability and commonly occurs in pulsed power applications. Using one-dimensional (1D) and two-dimensional (2D) axisymmetric resistive MHD simulations, the Virginia Tech team is modeling University of Nevada Reno and University of New Mexico experiments that pulse 0.8MA currents through 0.8mm diameter metallic rods in 100ns time-scales using the MYKONOS-V driver at Sandia National Laboratory. Lagrangian 1D simulations show liner melt times and velocity profiles of the outer surface of the liner that are similar to experimental values measured by collaborators. 2D simulations seeded with an initial surface perturbation show that mode growth occurs when a dielectric coating is present, but outward expansion slows as dielectric thickness increases.

This work was approved for release by Lawrence Livermore National Laboratory under release number LLNL-ABS-824315.