Study of soft X-ray radiation of plasma produced by interaction of laser radiation with copper targets at the “Kanal-2” facility

As part of the work on creating an x-ray microscope, experimental and theoretical studies of laser plasma of solid copper targets in the soft x-ray range were carried out. With a laser pulse duration of 2.5 ns (FWHM), the power density of the Nd:glass laser on the target is varied in the range 0.8 × 1013–4.2 × 1013 W/cm2. Experimental results demonstrated the presence of intense plasma emission in spectral ranges of water and carbon windows, and the number of photons of the most intense lines was calculated. Spatio-temporal studies of copper plasma have demonstrated intense emission in the wavelength range shorter than 15 Å, and the images of plasma emission in time-integrated and linear sweep modes are shown. The simulations of the interaction of the specified laser radiation flux with copper targets were carried out taking into account the transfer of self-radiation in plasma. The non-local thermodynamic equilibrium optical properties of the plasma were used. As a result of calculations, profiles of density, temperature, electron thermal conductivity flux, emissivity of plasma, and self-radiation flux were obtained. The calculated spectrum of the outgoing radiation is consistent with that obtained at the experiment.