X-ray laser interferometry for probing high-density plasmas

Collisionally pumped soft x-ray lasers now operate over a wavelength range extending from 4 - 40 nm. With the recent advances in the development of multilayer mirrors and beamsplitters in the soft x-ray regime, we can utilize the unique properties of x-ray lasers to study large, rapidly evolving laser-driven plasmas with high electron densities. Using a neon-like yttrium x-ray laser which operates at a wavelength of 15.5 nm, we have performed a series of x-ray laser interferometry experiments to characterize plasmas relevant to inertial confinement fusion. In this paper we describe experiments using a soft x-ray laser interferometer, operated in the Mach-Zehnder configuration, to study CH plasmas and exploding foil targets commonly used for x-ray laser targets. The two-dimensional density profiles obtained from the interferograms allow us to validate and benchmark our numerical models used to study the physics of laser-plasma interactions.