On the hot electrons and K _α x-rays generation in the intense laser interaction with silver targets

Intensity dependence of the conversion efficiency of laser energy into the energy of hot electrons is determined with the aid of measurements and modeling of K _α -photon yield from silver targets irradiated by relativistically intense subpicosecond laser pulses. We take into account intensity dependence of the effective hot electron temperature assuming the Wilks' scaling. The measurements reveal approximately the same values of the K _α yield from a silver foil of 10 μ m thickness, attached onto aluminium or plexiglass substrates, at the intensities about 10¹⁸ W/cm² and 2 × 10¹⁹ W/cm². Intensity dependence of the K _α yield from the silver foil, calculated using determined conversion efficiency of laser energy into the energy of hot electrons, is in agreement with the measurements. (paper)