406 / 2019-02-28 19:32:47

Preliminary study of driven uniformity by VISAR

Driven uniformity, VISAR diagnostic, Inertial confinement fusion

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Inertial confinement fusion driven by lasers requires a very high degree of uniformity in the deposition of laser energy on target in order to assure both a high degree of compression and ignition. Many teams have been researching on how to suppress drive nonuniformity. Driven nonuniformity has harmful influence on data obtaining in VISAR diagnostic, which will causes loss of signals. A method based on data of VISAR (velocity interferometer system for any reflector) for study of driven uniformity is proposed in this talk.
This talk is dedicated to exploring the relationship between shock wave measurement capability and driven uniformity so that to establish quantitative diagnostic capability. By analyzing the fringe pattern of VISAR, velocity history of shock wave can be obtained. Then shock wave velocity among spatial direction was obtained at different time. A large amount of data has been collected in different velocity(low speed at about 5Km/s, middle speed at about 20Km/s, high speed at about 50Km/s ) and different driven modes. Some conclusions were drawn by analyzing these with statistical means that better than 5% shock wave velocity uniformity is the precondition for VISAR to obtain data under current VISAR configuration. What’s more, an experiment was designed to verity the conclusions, which to be agree well with the conclusion.