Radiation Driven Icf Symmetry Analysis And 3 D Visualization Research

The radiation drive symmetry of a deuterium-tritium filled spherical capsule is one of the foremost issues in the indirect-drive approach to inertial confinement fusion (ICF).Understanding and controlling the processes affecting radiation drive symmetry of the capsule remains a crucial task for the laboratory ignition. This dissertation is based on the radiation drive symmetry, and the main research contents are as follows.Ⅰ A simplified dual-zone of laser spots and non-laser spots radiation model based on power balance in the hohlraum is presented in this paper. Then this model is used to analyze the results of experiments on implosion symmetry tuning made on the Shenguang-Ⅱ(SG-Ⅱ) and Shenguang-Ⅲ prototype(SG-Ⅲ YX) laser facilities. The calculations agree with the results of experiments. The parameters of the hohlraum and capsule on Shenguang-Ⅲ (SG-Ⅲ) facility are also studied. The variations of the best length-to-diameter ratio of cylindrical hohlraum and irradiation uniformity with the albedo of hohlraum’s inner wall, power ratio between inner and outer cones, motion of laser spots, sizes of diagnostic hole, diameters of the capsule and laser entrance hole and so on, are also discussed. This work can provide useful information for the design of implosion experiments on future.Ⅱ With the similarity model of X-ray confinement in cavity, the time-dependent redistribution of thermal X rays inside the hohlraum is calculated. Distribution of X-ray power intensity on the capsule’s surface is calculated via the view-factor method. After that, the time-dependent radiation drive symmetry of the capsule could be researched, including the implosion velocity of the capsule, X rays conversion efficiency and power ratio of laser between inner and outer cones. The uncertainties of implosion experiments, including pointing uncertainty of the capsule and laser beams, power balance uncertainty in cones and lack of laser beams, are also studied. And the sensitivity of radiation drive symmetry varying with these uncertainties is given. At last, multi-parameter-sets are scanned to reach the minimum of time-integrated of the second coefficient of Legendre polynomials. The best length-to-diameter ratio of hohlraum is about1.8, which is close to the one of experiments made on the National Ignition Facility (NIF), as well as the results of implosion symmetry tuning experiments on SG-Ⅱ and SG-Ⅲ prototype laser facilities.Ⅲ The software on analysis of radiation symmetry on the surface of the capsule and3dimension visibility is developed with CAD Center of Huazhong University of Science&Technology. The dual-zone radiation model introduced above is implanted into the code to the visibility research of radiation drive symmetry. This article demonstrates the layout of the chamber and laser subassembly, complex3-D geometries associated with beam-target-diagnostics orientations, calculations of radiation temperature and distribution of the power intensity on the capsule’s surface and the chosen section with the software. This software can be used as a design tool for high-energy density physics experiments.Through the research of this dissertation, an aided design tool on radiation drive symmetry and3-D visibility of the capsule is presented.