X-ray and optical diagnostics of a 100-fs laser-produced plasma

Solid targets have been irradiated by 80 fs laser pulses at 1017 W/cm2 laser irradiance. Spectra obtained in the 0.7 - 0.9 nm wavelength range show that x ray emission occurs at near-solid electron densities (Ne $OM 1023 cm-3). The analysis of the K(alpha) emission line points out the role of hot, fast electrons in the interaction physics. A time-resolved Schlieren imaging technique shows that the ultrashort laser pulses strikes a preplasma created by the laser-amplified spontaneous emission (ASE) with an electron density gradient scale length less than 1 micrometers.