Investigation of a laser-produced cerium plasma by the analysis of the high-resolution x-ray spectrum

Abstract

A highly stripped cerium $(Z=58)$ plasma is produced by irradiating a solid cerium target with a short pulse laser. The x-ray spectrum emitted from the plasma is recorded in the limited wavelength range 9.0--9.3 \AA{} using a high-resolution curved mica crystal spectrometer. The high-resolution spectrum, which corresponds to the $3d\ensuremath{-}5f$ transitions in Ni-, Cu-, and Zn-like cerium ions, is analyzed by means of a detailed collisional-radiative model that includes autoionization and dielectronic capture processes. The intensity ratio of the Ni-like $3d\ensuremath{-}5f$ resonant line at 9.045 \AA{} to the features emitted from satellite transitions of Cu-like ions provides an estimate for the mean electron temperature and density of 230 eV and ${10}^{22} {\mathrm{cm}}^{\mathrm{\ensuremath{-}}3},$ respectively. The deduced mean electron temperature is higher than that obtained in a similar experiment on laser-produced barium plasma. The origin of the higher mean electron temperature deduced in the present experiment is explained by the different type of transition employed for the temperature diagnostics, which might reflect a different phase of the plasma evolution.