Reemission technique for symmetry measurements in Hohlraum targets containing a centered high-Z ball.

A technique for measuring time-resolved drive symmetry in a laser-irradiated {ital Hohlraum} is presented. Design considerations and experimental method and results are emphasized. The experimental method involves x-ray imaging a high-{ital Z} ball placed in the center of a laser irradiated {ital Hohlraum}. We will show that the reemitted x-ray image can be measured as a function of time and that the images are directly related to the radiation flux asymmetry within the {ital Hohlraum}. Results from a series of experiments performed on the Nova laser located at Lawrence Livermore National Laboratory will be presented as well as a method for comparing with theoretical calculations. Detailed comparisons between theoretical calculations and experimental results will be given. {copyright} {ital 1996 The American Physical Society.}