Hot-electron characterization fromKα measurements in high-contrast,p-polarized, picosecond laser-plasma interactions

Strong K{α} emission is observed in picosecond laser-plasma interactions with high-intensity-contrast, p-polarized, picosecond laser pulses. K{α} 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 K{α} emission indicates that the solid is heated to a temperature of 35 eV up to 5000 {} from the target surface, which is consistent with the preheat of the hot electrons.