We present the first x-ray spectroscopic measurements of the ionization balance in inertial confinement fusion hohlraums supported by $4\omega$ Thomson scattering diagnostics. The experimental data show agreement with non-LTE radiation-hydrodynamic calculations of the averaged Au charge state and electron temperatures. These findings are consistent with the successful integrated modeling of the hohlraum radiation fields. Comparisons with detailed synthetic spectra calculations show that the experimental ionization distribution is slightly shifted indicating nonsteady state kinetics.

• Received 22 December 2000

DOI:https://doi.org/10.1103/PhysRevLett.87.045002