We have designed and produced hot, millimeter-scale, high-Z plasmas of interest for National Ignition Facility hohlraum target design. Using a high-Z gas fill produces electron temperatures in the 3.5–6-keV range, the highest temperatures measured to date for high-density ${(10\mathrm{}}^{21}e/{\mathrm{cm}}^3)$ laser-heated plasmas, and much higher than the 3 keV found for low-Z (neopentane) fills. These measurements are in good agreement with the target design calculations, and the L-shell spectroscopic approach used to estimate the electron temperature has certain advantages over traditional K-shell approaches.

• Received 17 August 1998

DOI:https://doi.org/10.1103/PhysRevE.59.6053