Ultraviolet Thomson Scattering from Direct-Drive Coronal Plasmas in Multilayer Targets

Ultraviolet ($\lambda_{4\omega} = $ 263 nm) Thomson scattering (TS) was used to probe ion-acoustic waves (IAW's) and electron plasma waves (EPW's) from direct-drive coronal plasmas. Fifty-nine drive beams ($\lambda_{3\omega} = $ 351 nm) illuminate a spherical target with a radius of $\sim 860 \mu$m. A series of experiments studied the effect of higher electron temperature near the 3$\omega $ quarter-critical surface ($\sim 2.5 \times 10^{21}$ cm$^{-3}$) on laser--plasma interactions resulting from a Si layer in the target. Electron temperatures and densities were measured from 150 to 400 $\mu$m from the initial target surface. Standard CH shells were compared to two-layered shells of CH and Si and three-layered shells of CH, Si, and CH. These multilayer targets have less hot-electron energy than standard CH shells as a result of higher electron temperature in the coronal plasmas. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.