Nonlinear growth of density fluctuations in the 3-dimensional self-gravitating systems

宇宙层次结构的形成都与三维自引力系统中密度涨落的非线性增长有关。在本研究项目中，对构造形成过程中的重力特征进行了数值和解析研究。本课题主要分为以下三个部分：1.利用三维数值模拟程序和线性理论，对等温云的稳定性和碎裂进行了深入的分析。用准非线性方法分析了环面中的角动量输运。系统分析了磁场在云演化中的作用。崩塌和超新星计算三维引力崩塌的程序已经开发完成。首次用后牛顿近似计算了核子星合并过程中的引力波发射，并对其波形进行了深入研究。超新星爆炸首先是用三维代码计算的，并暗示了抛射中块状结构的形成。还研究了X射线和伽马射线在超新星喷出物中的传播。结合突变理论，研究了一维薄片自引力系统的宇宙学动力学特征。对宇宙学的各种问题也进行了研究。

Structure formations in the hierarchy of the universe are all related with the nonlinear growth of density fluctuations in the 3-dimensional self-gravitating system. In this research project, the characteristics of gravity in the structure formation was studied numerically as well as analytically. The subject is classified to the following three:1. Cloud and Stars Stability and fragmentation of an isothermal cloud was analyzed extensively by the 3-dimensional simulation code and the linear theory. Angular momentum transportation in the toras was analyzed by the quasi-nonlinear method. Effect of magnetic field in the evolution of cloud was systematically analyzed.2. Collapse and Supernova The code to compute the 3-dimensional gravitational collapse has been developed. Gravitational waves emission in the process of nertron stars coalescence was firstly computed by the post Newtonian approximation and the wave form was extensively studied. Supernova explosion was firstly computed by the 3-dimensional code and suggested the formation of clumpiness in the ejects. Propagation of X and gamma ray in the supernova ejecta was also studied.3. Cosmology Dynamical feature of 1-dimensional sheetlike self-gravitating system was studied in relation to the catastrophy theory. Various problems of cosmology were also studied.