Diagnostics of electron temperature time evolution in radiation ablated low- Z materials

Abstract In indirect-drive inertial confinement fusion research, precise diagnostics of ablator electron temperature evolution are essential for understanding radiative ablation behavior. Using silicon-traced CH samples with point-projection backlighting, we measured time-resolved backlight spectra and silicon plasma absorption spectra at different times, deriving transmission spectra. Radiation temperature on sample was determined via the 3D view-factor code IRAD3D, while radiation-hydrodynamic simulations provided the evolution of electron temperature and density in the silicon plasma. By comparing experimentally measured transmission spectra with theoretically calculated spectra at varying electron temperatures, we inferred the electron temperature of the silicon plasma. Results reveal a rise-then-fall electron temperature trend in the silicon layer, with agreement between experiment and simulation during the temperature decline phase but discrepancies in the rise phase due to ionization-state complexities. This work elucidates electron temperature evolution and transport mechanisms during radiative heat wave propagation in low- Z materials.