Magnetic compression and solid-liquid phase transition of current-carrying conductors measured by photon Doppler velocimetry.

Metal conductors pulsed with intense electrical current are of fundamental importance to physics and engineering, yet their motion, equation-of-state (EOS), and electrical conductivity during the solid-liquid phase transition are not fully understood. Photon Doppler velocimetry (PDV) measurements of electrically thick aluminum, copper, and nickel conductors pulsed by intense current reveal that the reflective surface undergoes distinct changes in acceleration throughout the current rise. Metal surfaces were measured with sufficient resolution to capture radial magnetic compression and changes in radial acceleration that, in a model-assisted framework, diagnose the duration of the solid-liquid phase transition. Parylene-N-coated copper and nickel loads exhibited different compression dynamics. These experimental measurements serve as a benchmark, guiding the selection of EOS and conductivity tables for improved modeling and simulation accuracy.