  We present measurements of hard x-rays in the 50-300 keV range from copper
plasmas produced by 100 fs, 806 nm laser pulses at a peak intensity ~ 1016 W
cm-2. Surface roughness, even at the tens of nanometer level, is shown to
influence the emission characteristics. The enhanced emission from rough
targets is attributed to depolarization of light as well as extra absorption
facilitated by the surface irregularities.
