Space-resolved keV spectroscopy study of neonlike x-ray laser plasmas created with low-level prepulse irradiation

摘要

Abstract: Through the use of time-integrated space-resolved keV spectroscopy, we investigate line plasmas showing gain for irradiation using the prepulse technique. The experiments were conducted with the LULI laser of the Ecole Polytechnique, Palaiseau (France), at 1.06 micrometer with prepulse-to-main pulse intensity ratio ranging from 10$+$MIN@6$/ to 10$+$MIN@2$/. The particular x-ray lasers which were studied were the collisionally excited Ne-like zinc, copper and nickel systems. The effect of the prepulses on plasma conditions are inferred through spectroscopic line ratio diagnostics. It is observed that the value of the electron temperature for each system does not vary significantly with prepulse levels, nor does their spatially resolved profile along the line. The lateral width and density of the Ne-like regions in the plasmas of all three x-ray lasers are seen to increase with the prepulse level. !28