Publications
Benchmarking 3D-MHD simulations of electrothermal instability growth by studying z-pinches with engineered defects
The electrothermal instability (ETI) is driven by Joule heating and arises from the dependence of resistivity on temperature. ETI may drive azimuthally correlated surface density variations which seed magneto Rayleigh-Taylor (MRT) instability growth. Liner implosion studies suggest that dielectric surface coatings reduce the amplitude of ETI driven perturbations. Furthermore, previous fundamental physics studies suggest that non-metallic inclusions within the metal can seed ETI growth. In this project, we aimed to (1) determine how dielectric coatings modify ETI growth by varying the coating thickness and the surface structure of the underlying metal, and (2) study overheating from engineered defects--designed lattices of micron-scale pits. Engineered pits divert current density and drive local overheating in a way that can be compared with 3D- MHD simulations. All experiments were executed on the Sandia Mykonos Facility. Facility and diagnostic investments enabled high quality data to be gathered in support of project deliverables. ACKNOWLEDGEMENTS Supported in part by the LDRD Program at Sandia National Laboratories (Projects 178661/200269). Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under Contract No. DE-NA-0003525.