Dimensional Non-equilibrium Radiation Hydrodynamics Code Developed And Applied Research

For its unique advantages,x-ray laser has significant prospects of applications in physics,biology,chemistry,materials science and ICF fields.After 20 years' development,the saturated output of XRL has been obtained,and now all laboratories all over the world have beginning the research of its application demonstration.In the study of XRL,we more and more find that the 1D study can't catch up with the step of XRL theoretical deep study,and the study of diagnosing of ICF plasma by XRL also desires a 2D code.Only through 2D study,we can understand complicated filed image structures of XRL,and carefully optimize XRL experiments of single- and multi-targets to get higher intensity of XRL,we can more professionally design plasma to be probed in XRL density diagnosis,and explain the experimental results of electron density diagnosis,to fulfill the goal of testing theoretical models.In order to adapt those requirements,in the period of my PhD,I have developed the 1D code JB19 to a 2D non-equilibrium radiation hydrodynamic code,named XRL2D,and have completed some physical studies using this code.Single hydrodynamic model is used in XRL2D code,electron and ion have different temperatures.Flux-limit heat-conduction approximation and flux-limit multi-group diffusion approximation are adopted,and average atomic model is used in code.Split scheme is used,the diffusion processes is departed from local processes such as ionization and heating.The 9-piont differential scheme suggested by Kershaw is used in the calculation of 2D diffusions.The physical processes and calculating methods are detailed in this thesis.(1)The studies of calculating methods.In order to overcome the trouble of mesh distorting in Lagrange calculation,taking the advantage of strong anti-distorting for triangle meshes,a modified IGA scheme is proposed innovatively in thesis,and the attempts show that the mesh distorting are restrained effectively.But this method can also do nothing while real physical convolution and mixture of fluid existing,so the ALE method is adopted in code.In order to survey the numerical diffusion induced by mesh rezoning and variables remap in ALE method,some calculations had been done,and comparisons show that the smoothing does exist,but the numerical dissipation is not serious,it do no harm to physical picture.Furthermore,thesis includes the comparisons of simulation results between XRL2D and LASNEX code for same models to survey the reliability of code.And the possibility of displacing 9-point differential scheme by bidirectional 1D method is also discussed in thesis,for the latter can greatly decrease the calculation amount.(2)The studies of physical problem.Firstly,the experiment of quasi-steady-state Ni-like Ag XRL on ShenGuang-â…¡facility is simulated,the calculated results can well explain why the experimental field image of XRL show a crescent-shaped structure.Secondly,three recent experiments of electron density diagnosis by XRL on ShenGuang-â…¡also are simulated,those experiments are;electron density diagnosis of spot focused CH plasma by XRL M-Z interferometer,measurement of CH film driven by 2w laser using a XRL backlighter and measurement of fluid jet by XRL backlighter.Some simulation results agree with experimental results quantitatively, some results agree experiment only qualitatively,and some disagreements also exist. A theoretical design of electron density diagnosis application experiment by XRL is also given out in thesis,in which the plasma jetted out of Au half-hohlraum driven by laser will be measured.This simulation shows the calculating ability of XRL2D code.This thesis has been supported by the National High Technology 863 project of China(Grant No.863-804-7-1 and 803-804-1-10-1).