Comparison of excitation and kinetic temperatures in a laser-produced plasma using absorption spectroscopy.

High-resolution tunable laser absorption spectroscopy is used to measure time-resolved absorption spectra for six neutral uranium transitions in a laser-produced plasma. Analysis of the spectra shows that kinetic temperatures are similar for all six transitions, but excitation temperatures are higher than kinetic temperatures from 10-100 μs, indicating departures from local thermodynamic equilibrium.