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.