Simulation of the generation of the characteristic X-ray emission under vacuum heating of cluster electrons by a femtosecond laser pulse

We have developed a model for the generation of K_α radiation and the formation of hot electrons under vacuum heating by a femtosecond laser pulse near the surface of spherical clusters. The simulation results correspond to measurements at a cluster diameter of less than or of the order of the wavelength for the cases of p-polarised laser radiation and radiation incident along the normal to the surface. We discuss a significant decrease in the conversion of the laser energy into the energy of K_α emission with decreasing wavelength from 1.24 to 0.4 μm, which is observed at an intensity of 2 × 10¹⁷ W·cm^-2.