Temperature measurement of Warm Dense Matter using Streaked Optical Pyrometry

The study of Warm Dense Matter (WDM) is of great interest for both inertial confinement fusion and fundamental science. WDM is a type of plasma that exists in a temperature range from 10-100 eV and has a density around the same magnitude or higher than the solid state. A common challenge to all plasma experiments is being able to accurately measure these physical conditions, however, is of the utmost importance for benchmarking hydrodynamic simulations. Here we report on a WDM target characterization using Streaked Optical Pyrometry (SOP). The experiment was performed at the ALEPH laser facility, where WDM conditions were generated by irradiating a thin 1 μm carbon foil with a heater laser of 500 fs pulse duration and 1 J of energy, yielding 5x1015 W/cm2 on target.

A streak optical pyrometer was used to infer the WDM temperature at the critical density by converting a measurable intensity of light, with appropriate temporal, spatial and spectral resolution, to an equivalent blackbody temperature at a given wavelength. Using a 532 nm interferometric filter, we were able to obtain temporally resolved measurements of the WDM temperature at the corresponding critical density. The experimental measurements are then compared with 1D MULTI-fs and RALEF-2D hydrodynamic simulations.