THEORETICAL AND EXPERIMENTAL STUDIES OF LASER-PRODUCED PLASMAS DRIVENBY HIGH-INTENSITY FEMTOSECOND LASER-PULSES

A theoretical and experimental study of the dynamics of the electron d ensity gradient in near-solid-density plasmas produced by the interact ion of ultra-short laser pulses with solid targets at intensities betw een 10(13) and 10(16) W/cm(2) and pulse duration between 0.12 and 2.5 ps is presented. X-ray spectroscopy of n = 3 to n = 1 resonance and di electronic satellite lines is used to determine the range of electron densities in the plasma. Frequency-domain interferometry is employed t o measure the expansion velocity and the electron density gradient sca le length as a function of laser pulse duration and intensity. Quantit ative agreement is noticed with one-dimensional hydrodynamic simulatio ns which include the solution of the wave equation for the laser held. (C) 1997 American Institute of Physics.