Evidence for profile steepening in laser-irradiated plasmas

Experimental evidence of a steepened electron density profile near critical density has been obtained by studying the light scattered by targets (10-μm thick disks and 100-μm diam glass spherical microshells filled with deuterium and tritium gas) illuminated by linearly polarized, 1.06-μm light. Scale lengths on the order of 1 μm have been inferred both from the polarization of the reflected light and from the azimuthal asymmetry (asymmetry about the beam axis) of the time-integrated scattered light with respect to the laser electric field. Azimuthally asymmetric heating of the microshells targets is indicated both by x-ray micrographs and by the spatial distribution of the plasma blowoff.