Density and x-ray emission profile relationships in highly ionized high-<i>Z</i> laser-produced plasmas

Abstract

We present a benchmark measurement of the electron density profile in the region where the electron density is 1019 cm–3 and where the bulk of extreme ultraviolet (EUV) emission occurs from isotropically expanding spherical high-Z gadolinium plasmas. It was found that, due to opacity effects, the observed EUV emission is mostly produced from an underdense region. We have analyzed time-resolved emission spectra with the aid of atomic structure calculations and find the multiple ion charge states around 18+ during the laser pulse irradiation.