黑洞吸积盘中大尺度磁场的形成和演化

Jet, which is a research focus in modern astrophysics, is extensively present in various celestial systems. Large-scale magnetic fields are generally considered to play a key role on the formation of jet. However, the formaiton mechanism of large-scale magnetic fields is still an unsolved issue so far. In this project, combining with the results in MHD simulations, we will mainly study the sticking point on the formation of large-scale magnetic fields, i.e., the formation and evolution of large-scale magnetic fields in a thin accretion disk. Firstly, we will investigate the possibility to magnify the large-scale magnetic fields through a disk corona. Secondly, we will research the time-dependent evolution of large-scale magnetic fields in a thin accretion disk and the effects of both the outer boundary conditions and the initial conditions. Thirdly, the stability of large-scale magnetic fields will also be the research objective of this project. Fourthly, through X-ray observations, we will validate the presence of magnetized accretion disks, which should be formed in the inner accretion disk region by accumulating enough magnetic flux. At last, the correlation bewteen viscosity parameter and the magnitude of vertical magnetic field will also be validated by observations.

喷流广泛地存在于各种天体物理系统中，是当今天体物理研究的一个热点。人们一般认为大尺度磁场在喷流的形成过程中起着极其关键的作用。然而，迄今大尺度磁场是怎么形成的还是一个未解决的问题。本项目将结合数值模拟的结果来着重研究大尺度磁场形成的难点---即大尺度磁场在薄盘中的形成与演化问题。本项目将研究大尺度磁场通过冕吸积放大的可能性；研究大尺度磁场在薄盘中的含时演化，研究外边界条件和初始条件对结果的影响；研究薄盘中大尺度磁场的稳定性；此外，大尺度磁场很可能会在吸积盘的内区堆积形成磁吸积盘，因此我们将研究其在X射线辐射的观测验证；最后，我们还将利用观测结果来验证粘滞系数与垂向磁场强度之间的相关性。

喷流广泛地存在于各种天体物理系统中，是当今天体物理研究的一个热点。人们一般认为大尺度磁场在喷流的形成过程中起着极其关键的作用。然而，迄今大尺度磁场是怎么形成的还是一个未解决的问题。我们研究了薄吸积盘中大尺度磁场的形成过程，发现磁场所驱动的外流有助于放大外边界的大尺度磁场。此外，还对其他相关方向进行了多方面的研究，如射电噪活动星系核X射线的起源，认为其应该主要来自于盘冕系统而不是喷流；射电宁静类星体光变的物理机制；大尺度磁场对变脸活动星系核的影响等。