X-ray emission measurements from CO2-laser-created plasmas

Results of the interaction of gigawatt nanosecond CO2 pulses with various solid targets are reported. The x-ray emission as a function of focusing is not critical within ± 1 mm of the on-target position. The x-ray intensity has an approximate power law dependance of 2.5 with laser energy for all elements. Densitometer analysis of sections of the x-ray pinhole pictures indicate nonuniformities in the plasma and localized hot spots. Line spectra taken with a Bragg crystal indicate temperatures of 200 eV for 4 J of incident energy. Continuum spectra taken with absorbants show characteristic nonthermal behavior, which may be related to parametric instabilities. The x-ray yield as a function of atomic number exhibits a series of peaks which are similar in position to the predictions of a coronal model.