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

Abstract

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.