Research of relativistic radiation hydrodynamics in supernovae

本文从三个方面研究了像WolfRayet星这样具有剥离包膜的大质量恒星的超新星爆炸现象。1. 使用相对论流体力学代码进行了数值计算，以研究暴露其C-O核心的大质量恒星的最外层包层的加速度。随后加速的C和O （He）与H和He (N)的相互作用也被研究，以估计通过散裂（和/或聚变）反应的轻元素（Li， Be和B）的数量。已经证明，即使在星系的早期阶段，这些过程也可以在快速旋转的恒星中实现，并且增加了恒星周围星周物质中这些元素的含量，这表明具有大量轻元素的恒星可以在婴儿星系中形成2。在平面平行几何中发现了描述超相对论激波通过恒星表面以及随后与星周物质的流体动力学相互作用的两个自相似解，后一解扩展到包括恒星表面球形的影响。通过与数值计算结果的比较，验证了该推广方法的有效性。3. 本文通过数值计算研究了二维实空间和三维动量空间的Vlasov-Maxwell系统中两个等离子体与反流的电磁相互作用。我们观察到细丝结构的形成，磁场的放大，这些细丝的合并，以及与之相关的磁场构型的变化。由于中间态表现为准稳态，我们发展了这种状态的解析表达式，将分布函数的偏差从麦克斯韦-玻尔兹曼分布扩展到埃尔米特多项式系统。

Phenomena associated with supernova explosions of massive stars with stripped envelope like WolfRayet stars are investigated from three aspects. 1. Numerical calculations using a relativistic hydrodynamics code were performed to investigate the acceleration of the outer most envelopes of massive stars exposing their C-O cores. The subsequent interaction of the accelerated C and O (He) with H and He (N) is also investigated to estimate the amount of light elements (Li, Be, and B) through spallation (and/or fusion) reactions. It has been shown that these processes can be realized in a rapidly rotating star even in the early stages of a galaxy and enhance the contents of these elements in the circumstellar matter around the star This indicates that stars with large amount of the light elements could form in an infant galaxy 2. Two self similar solutions describing the passage of an ultra-relativistic shock through the stellar surface and the subsequent hydrodynamical interactions with the circumstellar matter are discovered in the plane parallel geometry The latter solution is extended to include the effect of the spherical shape of the stellar surface. A comparison with results from numerical calculation is made to estimate the validity of this extention. 3. We have investigated electromagnetic interactions of two plasmas with counter streams by numerical calculations for Vlasov-Maxwell systems with 2-D in real-space and 3-D in momentum space. We have observed the formation of filamentary structure, amplifying magnetic fields, the merging of these filaments, and the associated change of the configuration of magnetic fields. Because the intermediate states appear as quasi- stationary state, we have developed an analytical expression for this state expanding the deviation of the distribution function from the Maxwell-Boltzmann distribution into the Hermite polynomial systems.