Two-dimensional effects in laser-created plasmas measured with soft-x-ray laser interferometry

Soft-x-ray laser interferograms of laser-created plasmas generated at moderate irradiation intensities (1×10¹¹--7×10¹²Wcm^-2) with λ=1.06μm light pulses of {~}13-ns-FWHM (full width at half maximum) duration and narrow focus ({~}30 {μ}m) reveal the unexpected formation of an inverted density profile with a density minimum on axis and distinct plasma sidelobes. Model simulations show that this strong two-dimensional hydrodynamic behavior is essentially a universal phenomena that is the result of plasma radiation induced mass ablation and cooling in the areas surrounding the focal spot.