The Temperature of Fe at 3 Mbar

We report on progress toward converting the measured surface temperature (T) of Fe at ~3 Mbar (near melt, on the Hugoniot) into a bulk temperature measurement as part of an effort to obtain a complete equation of state for Fe. Fe was directly coated on a LiF tamping window and shock compressed using a two-stage light gas gun. Radiance and reflectance were simultaneously measured from ~350-750 nm using four streak spectrometers. T was determined through comparison of reflected and emitted light, allowing us to calculate emissivity as a function of wavelength to correct graybody emission. We will also present results from 2D hydro simulations including heat transport, release wave propagation, and sensitivity to Fe/LiF material properties.