TEMPORAL CHARACTERISTICS OF BACKSCATTERED LIGHT FROM A KRF LASER-PRODUCED PLASMA

We report measurements of the time-resolved spectra of backscattered l ight, near the incident laser wavelength (0.25 mu m), from aluminum pl asmas produced by nanosecond pulse KrF laser radiation at an intensity similar or equal to 10(14) W/cm(2). The redshifted scattered light sh ows the characteristic temporal and spectral features of stimulated Br illouin scattering. The observed spectral linewidth (similar or equal to 0.3 Angstrom) can be accounted for by inhomogeneity in the plasma f low velocity and density. The experimental results are compared with m odel predictions of the spectral shift using a two-dimensional hydrody namic simulation computer code (CASTOR). The dynamics of the spectral shift show a strong correlation with the laser pulse shape, indicating the importance of inverse bremsstrahlung absorption for short wavelen gth laser radiation and heat transport in a highly collisional plasma.