X-ray spectral measurements and collisional-radiative modeling of hot, gold plasmas at the omega laser

M-Band and L-Band Gold spectra between 3 and 5 keV and 8 and 13 keV, respectively, have been recorded by a photometrically calibrated crystal spectrometer. The spectra were emitted from the plasma in the laser deposition region of a ‘hot hohlraum’. This is a reduced-scale hohlraum heated with ≈9 kJ of 351 nm light in a 1 ns square pulse at the OMEGA laser. The space- and time-integrated spectra included L-Band line emission from Co-like to Ne-like gold. The three L-Band line features were identified to be the 3s → 2p, 3d5/2 → 2p3/2 and 3d3/2 → 2p1/2 transitions at ≈9 keV, ≈10 keV and ≈13 keV, respectively. M-Band 5f → 3d, 4d → 3p, and 4p → 3s transition features from Fe-like to P-like gold were also recorded between 3 and 5 keV. Modeling from the radiation–hydrodynamics code LASNEX, the collisional-radiative codes FLYCHK and SCRAM, and the atomic structure code FAC were used to model the plasma and generate simulated spectra for comparison with the recorded spectra. Through these comparisons, we have determined the average electron temperature of the emitting plasma to be between 6.0 and 6.5 keV. The electron temperatures predicted by LASNEX appear to be too large by a factor of about 1.5.