Generation of Hot Electron at Higher Temperature from SolidPlasma with a Moderate-Intensity Femtosecond Laser

We experimentally investigate the generation of hot electrons from the interaction of a moderate-intensity (10¹⁶W/cm²) pre-pulsed-free femtosecond laser (6 mJ, 120 fs, at 744 nm) with a solid target. The temperature of the hot electrons is inferred from the hard x-ray ( > 30 keV) continuum. The measured hard x-ray continuum is fitted by the Maxwellian distribution with two hot-electron temperatures of 45 and 85 keV. Electrons with the lower temperature were accelerated by “vacuum heating”. However it is necessary to carry out an accurate numerical simulation to explain the generation of hot electrons at higher temperature.