Research of relativistic radiation hydrodynamics in supernovae

本文从三个方面研究了具有剥离包层的类沃尔夫-拉叶星的超新星爆炸现象。1.利用相对论流体动力学程序对暴露出C-O核的大质量恒星最外层包层的加速度进行了数值计算。此外，还研究了加速的C和O（He）与H和He（N）的后续相互作用，以估计轻元素（Li，Be和B）通过溅射（和/或聚变）反应的量。研究表明，即使在星系形成的早期阶段，快速旋转的星星也能实现这些过程，并使这些元素在星星周围的星周物质中的含量增加。这表明，具有大量轻元素的恒星可以在婴儿星系2中形成。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。通过与数值计算结果的比较，验证了这种推广的有效性。3.通过对实空间二维和动量空间三维的Vlasov-Maxwell系统的数值计算，研究了两个等离子体与逆流的电磁相互作用。我们观察到了磁纤维结构的形成、磁场的放大、磁纤维的合并以及相应的磁场位形的变化。由于中间态表现为准定态，我们将其分布函数与Maxwell-Boltzmann分布的偏差推广到Hermite多项式系统中，得到了准定态的解析表达式。

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.