General relativistic theory of charged accretion disk structures around black holes: influence of the (self)-electromagnetic interaction

黑洞周围带电吸积盘结构的广义相对论理论：（自）电磁相互作用的影响

• 批准号: 510727404
• 负责人: Professor Dr. Claus Lämmerzahl
• 金额: --
• 依托单位: Zentrum für angewandte Raumfahrttechnologie und Mikrogravitation (ZARM)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/510727404?language=en
• 关键词: General; relativistic; theory; charged; accretion

In this project, we focus on accretion disks as charged perfect fluids. Electromagnetic fields are well known to have a strong influence on the structure, physics and evolution of accretion disks around compact objects like black holes or neutron stars. Since black holes cannot be observed directly and since accretion disks can approach the central compact object very closely, they are a perfect probe of the strong gravity or near-horizon regime and of the physics of the black holes and neutron stars. A full analysis of accretion disks has to include a combination of a variety of settings and influences. In case of an accretion disk made of a charged fluid, the influence of the charge of the disk on itself appears as one of the inevitable effects which are still mainly unexplored. For such complex problems, it is natural to first study the situation using idealized models offering analytic approaches, which provide a -- within the model -- thorough insight into the physical mechanisms. For a complete understanding general relativistic magneto-hydrodynamical simulations have to be carried through. Our primary focus is on accretion disks modeled by an ideal charged fluid within the geometrically thick disk framework. We will proceed in three steps: (i) We will determine the influence of the electromagnetic self-interaction on the disk. To start with, the electromagnetic field of the disk will be described as emerging from a charged ring on the disk center and acting on the disk. In a successive approximation procedure, we will determine the Faraday tensor of the entire disk. We will describe the influence of the induced field on the properties of the accretion disk. (ii) We study the oscillations and stability of the charged thick disk model including the self-field determined in (i). We analyse the oscillation modes and compare that result with the observations of high frequency quasi-periodic oscillations. From second order analysis of applied perturbations, we then will investigate the temporal evolution of the various charged thick equilibrium solutions. (iii) Finally, if time permits, we will consider a toy model to reproduce the polarized image of the center of M87 released by the Event Horizon Telescope collaboration. This image depends, among many other effects, on the magnetic field geometry and the space-time curvature. In all cases we try to find exact or approximate analytic solutions. In cases where this is impossible we will also apply numerical methods.

在这个项目中，我们将重点放在积聚的磁盘上，作为充电的完美液体。众所周知，电磁场对紧凑型物体（如黑洞或中子恒星）周围的积聚盘的结构，物理和进化具有很大影响。由于无法直接观察到黑洞，并且由于积聚磁盘可以非常接近中心紧凑的物体，因此它们是对强力或接近胜利状态以及黑洞和中子星体物理学的完美探测。对积聚磁盘的完整分析必须包括各种环境和影响的组合。如果有带电液体的积聚盘，则磁盘的电荷对本身的影响似乎是不可避免的效果之一，这些效果仍未得到探索。对于这种复杂的问题，自然可以使用提供分析方法的理想化模型首先研究情况，这些模型在模型中提供了对物理机制的详细见解。为了完全理解一般相对论的磁性磁动力学模拟。我们的主要重点是通过在几何厚度磁盘框架内建立理想带电的流体建模的积聚磁盘。我们将分三个步骤进行：（i）我们将确定电磁自我相互作用对磁盘的影响。首先，磁盘的电磁场将被描述为从磁盘中心的带电环中出现并在磁盘上作用。在连续的近似过程中，我们将确定整个磁盘的法拉第张量。我们将描述诱导场对积聚磁盘性能的影响。 （ii）我们研究带电厚的磁盘模型的振荡和稳定性，包括（i）中确定的自场。我们分析了振荡模式，并将结果与​​高频准周期振荡的观察结果进行了比较。从应用扰动的二阶分析中，我们将研究各种带电厚的平衡溶液的时间演变。 （iii）最后，如果时间允许，我们将考虑一个玩具模型来重现活动地平线望远镜协作发布的M87中心的两极分化图像。此图像在许多其他效果中都取决于磁场几何形状和时空曲率。在所有情况下，我们都试图找到精确或近似的分析解决方案。在不可能的情况下，我们还将采用数值方法。