Enhanced x-ray emissions from low-density high-Z mixture plasmas generated with intense nanosecond laser

•Low density high-Z mixture targets were proposed for significant x-ray emissions from laser-produced plasmas.•The effects of low initial density are to decrease kinetic loss and to increase soft x-ray emissions.•The main effect of high-Z mixture is to enhance x-ray emissions by coronal plasmas.•The two effects can be added together due to simulations.

Enhancement of x-ray emissions from laser-produced plasmas is imperative for various applications. Low-density Au–Gd mixture was proposed to enhance the x-ray emissions. X-ray emissions were simulated for the laser-irradiated gold and Au–Gd mixtures with different initial densities. It was shown that 1.34 times conversion efficiency has been achieved for the 0.05 g/cm30.05 g/cm3 Au–Gd (6/4)(6/4) mixture comparing with the 10 g/cm310 g/cm3 gold. The enhancement is attributed to higher Rosseland mean opacities of the mixture and reduction of the ion kinetic energy caused by the lower initial density.