Hohlraum $T_{\mathrm{e}}$ Inferred from Au L-Shell Emission

Laser-ablation plasmas created at the inner wall of the hohlraum (Au bubble) and at the laser entrance hole (LEH) radiate L-shell emission from Ne-like to Co-like charge states of Au. A 1-D spatially resolved and time-integrated spectrum in the 6- to 16-keV range with $E$/d$E = $ 100 to 300 is recorded along the axis of the hohlraum. The Au L-shell spectral line shapes of the $2p_{3/2} - 3s$, $2p_{3/2} - 3d_{5/2}$, and $2p_{1/2} - 3d_{3/2}$ transitions are analyzed using an atomic physics code to infer the $T_{\mathrm{e}}$ of the radiating plasma. Preliminary results indicate the Au LEH plasma of a near-vacuum hohlraum has an inferred $T_{\mathrm{e}}$ of 5 to 6 keV, while a gas-filled hohlraum has a significantly lower $T_{\mathrm{e}}$. A comparison of the Au L-shell spectra and the $T_{\mathrm{e}}$ sensitivity will be presented, along with the plan to measure the L-shell emission from the Au bubble. This material is based upon work supported by the Department Of Energy National Nuclear Security Administration under Award Number DE-NA0001944. Part of this work was performed under the auspices of the U.S. Department of Energy by LLNL under Contract DE-AC52-07NA27344.