HOT-ELECTRON CHARACTERIZATION FROM K-ALPHA MEASUREMENTS IN HIGH-CONTRAST, P-POLARIZED, PICOSECOND LASER-PLASMA INTERACTIONS

Strong Kalpha emission is observed in picosecond laser-plasma interactions with high-intensity-contrast, p-polarized, picosecond laser pulses. Kalpha emission from Si substrates overlaid with various thicknesses of Al is compared with a Monte Carlo simulation. The results show that the hot electrons which deposit their energy in the solid material have a 3-keV temperature and carry 10% of the incident laser energy. The shifted Kalpha emission indicates that the solid is heated to a temperature of 35 eV up to 5000 angstrom from the target surface, which is consistent with the preheat of the hot electrons.