Electron Density Measurements of High Density Plasmas Using Soft X-Ray Laser Interferometry

We have developed and used for the first time a soft x-ray interferometer to probe a large laser-produced plasma with micron spatial resolutions. A neonlike yttrium x-ray laser operating at 155 A was combined with a multilayer coated Mach-Zehnder interferometer to obtain electron density profiles in a plasma produced by laser irradiation of a CH target. The measured electron density profile has been compared to hydrodynamic simulations and shows good agreement near the ablation surface but some discrepancy exists at lower densities.