High temperature of laser-compressed shells measured with Kr³⁴⁺ and Kr³⁵⁺ x-ray lines

High electron temperatures (3–4 keV) have been achieved by imploding shells filled with a deuterium-krypton mixture on the OMEGA laser system, in agreement with hydrodynamic simulations. The temperature was deduced from the high-energy continuum slope in the range 8–20 keV, and from the intensity ratio of Kr³⁵⁺ to Kr³⁴⁺ x-ray lines. These results show the feasibility of obtaining higher temperatures than previously achieved in laser implosions and studying them using spectroscopy of sub-Å x-ray lines and continuum. © 1996 The American Physical Society.