TIME-RESOLVED AND SPACE-RESOLVED DENSITY EVOLUTION OF THE PLASMA WAVE-GUIDE

Detailed time- and space-resolved electron density measurements are pr esented for laser-produced plasma waveguides. A density depression sui table for optical guiding begins to develop within the first few hundr ed picoseconds after plasma generation, during which rapid cooling occ urs. At longer times the expansion closely follows that of a cylindric al blast wave, with further cooling due to expansion work. The wavegui de profile is uniform over most of its length, with the density depres sion appearing within 150 mu m of the ends.