<title>X-ray emission from ultrashort UV-laser-pulse-produced plasmas</title>

Abstract

X-ray K- and L-shell emission from aluminum and carbon plasmas produced by subpicosecond UV-laser pulses has been investigated using various spectrographs. The spectra have been measured as a function of laser intensity in the range from 10¹⁴ W/cm² to 10¹⁸ W/cm². A computer simulation including reabsorption of the resonance lines has been performed and the observed and calculated spectra compared. Plasma parameters have been deduced by line emission and continuous emission observations. It has been found that for high laser intensities the resonance line emission and that from the satellites comes from the overdense region. A scaling of the electron temperature with the irradiance has been obtained. From the x-ray spectra measured at different laser intensities, the thresholds for the formation of hydrogen-like and helium-like ions in aluminum and carbon plasmas have been determined.