TIME-RESOLVED, 2-DIMENSIONAL ELECTRON-TEMPERATURE DISTRIBUTION OF LASER-IMPLODED CORE PLASMAS

We have developed a multichannel, multiimaging x-ray streak camera tec hnique to measure two-dimensional electron-temperature distributions w ith a high temporal resolution by adding a multichannel spectrum selec tion capability to a multiimaging x-ray streak camera technique, and a pplied it to direct-drive implosion experiments with partially coheren t light at Gekko-XII laser facility. It was found that electron-temper ature distributions in the laser-imploded core plasmas of ICF targets had low-mode nonuniform structures changing with a temporal scale of 2 0 ps, and the abrupt drop of the electron temperature appeared in the deceleration phase. We have compared temporal profiles of the experime ntally observed x-ray intensity and electron-temperature with those pr edicted by a one-dimensional hydrodynamic code ''ILESTA'' to investiga te the hot spark heating in the core plasmas. (C) 1997 American Instit ute of Physics.