DETAILED 266 NM THOMSON SCATTERING MEASUREMENTS OF A LASER-HEATED PLASMA

Collective Thomson scattering at 266 nm is used to obtain spatially resolved, two-dimensional electron density, temperature, and radial drift profiles of a collisional laser plasma (critical density, n(c) = 1 x 10(21) cm-3). An ultraviolet diagnostic wavelength minimizes the complicating effects of inverse bremsstrahlung and refractive turning in the coronal region of interest, where electron densities approach n(c)/10. Laser plasmas of this type are important because they model some of the aspects of the plasmas found in high-gain laser-fusion pellets irradiated by long pulse widths (t(L) greater-than-or-similar-to 10 nsec), where laser light is absorbed mostly in the corona. The experimental results and LASNEX [Comments Plasma Phys. Controlled Fusion 2, 51 (1975)] simulations agree within a percent standard deviation of 40% for electron density and 50% for electron temperature and radial drift velocity. Thus it is shown that the hydrodynamics equations with classical coefficients and the numerical approximations in LASNEX are valid models of laser-heated, highly collisional plasmas.