PLASMA EVOLUTION FROM LASER-DRIVEN GOLD DISKS .1. EXPERIMENTS AND RESULTS

Gold disk targets were irradiated with green (λ = 0.53 μm) laser light at intensities between 0.5 and 5×1014 W/cm2 using shaped laser pulses. Plasma conditions near and below critical density (nc ≃ 4×1021/cm3) were determined from three diagnostics. Streaked one-dimensional images of the M-band emission (2-3,5 keV) along the laser axis yield the peak emission trajectory. Temporally and spatially averaged measurements of the hard x-ray spectrum (4-25 keV) were used to determine the average coronal electron temperature. Holographic interferometry was used to determine the electron density profiles and scale lengths along the laser axis. The peak emission trajectory, electron temperature, and scale lengths are all in good agreement with simulations, but the magnitudes of the electron density profiles are not, as discussed in an accompanying paper [Phys. Fluids B 2, 2448 (1990)]. © 1990 American Institute of Physics.