Sensitivity of magnetohydrodynamic simulations of Joule-heated conductors to the vaporization curve in equations of state

Magnetohydrodynamic (MHD) simulations of electrically exploded aluminum and copper rods demonstrate a technique to validate equations of state (EOS) for rapidly Joule-heated conductors. The balance of internal and magnetic forces at the conductor-insulator interface drives the metal there along the vaporization phase boundary. Variations between critical points and vaporization curves in existing models predict differing densities and temperatures in MHD simulations for these models. Here, the inclusion of Maxwell constructs in the liquid-vapor biphase region of the EOS caused the rod surface to vaporize earlier in time than unmodified tables with van der Waals loops. Velocimetry of recent experiments is used to validate the location of the vaporization curve in existing EOS models and differentiate between the vapor dome treatments. Dielectric coatings applied to the metal surface restricted the conductor’s expansion and diverted the metal into the warm dense matter regime.. Authors: Kreher, Seth E. [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States); Univ. of Nevada, Reno, NV (United States); University of Nevada, Reno] (ORCID:0000000187094887); Rousculp, Christopher L. [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)] (ORCID:0000000190723429); Bauer, Bruno S. [Univ. of Nevada, Reno, NV (United States)] (ORCID:0000000291358803); Hutchinson, Trevor M. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)] (ORCID:0000000318823702); Klemmer, Aidan W. [Univ. of Nevada, Reno, NV (United States)] (ORCID:0000000303804138). DOE Contract: 89233218CNA000001; AC52-07NA27344; NA0003870; NA0004136. Subjects: 36 MATERIALS SCIENCE; 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; EOS; MHD; Z-pinches; aluminum; copper; equations of state; high-energy-density plasmas; magnetohydrodynamics; phase space dynamics; plasma sheaths & surfaces; plasma thermodynamics; pulsed power; pulsed-power accelerators; reflectivity; simulations; warm-dense matter