Relativistic Jet Formation from Black Hole Magnetized Accretion Disks: Method, Tests, and Applications of a General RelativisticMagnetohydrodynamic Numerical Code
Relativistic Jet Formation from Black Hole Magnetized Accretion Disks: Method, Tests, and Applications of a General RelativisticMagnetohydrodynamic Numerical Code
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DOI：
10.1086/307667
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发表时间：
1999-09
期刊：
影响因子：
--
通讯作者：
S. Koide;K. Shibata;T. Kudoh
中科院分区：
文献类型：
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作者：
S. Koide;K. Shibata;T. Kudoh
相对论喷流在活动星系核（AGN）和银河系的“微类星体”中都有观测到。据信，这些相对论性喷流是从黑洞附近喷射出来的。为了研究这些喷流的形成机制，我们开发了一个新的广义相对论磁流体动力学（GRMHD）程序。我们报告的基本方法和测试计算，以检查代码是否再现一些分析的解决方案，如一个站立的冲击和开普勒磁盘与一个稳定的状态落入电晕或电晕在流体静力平衡。然后，我们将代码的形成相对论性MHD射流，调查吸积盘的动力学最初线程由一个统一的极向磁场在一个非旋转的日冕（无论是在稳定状态的下落或流体静力平衡）周围的非旋转黑洞。数值结果表明：随着时间的推移，由于磁制动的作用，盘失去角动量，福尔斯落入黑洞。由于广义相对论效应在3rS以下（rS是史瓦西半径），盘的下落运动比非相对论情况下更快，在r = 2rS附近由于离心力强烈减速，在盘内形成激波。磁场在差动旋转的作用下发生紧扭曲，在J × B力的作用下，圆盘冲击区的等离子体被加速，形成双极相对论喷流。此外，在这种磁驱动射流的内部，我们还发现了一种由气压力从冲击区喷出的气压驱动射流。这种双层射流结构不仅在静力电晕情况下形成，而且在稳态落电晕情况下也形成。
Relativistic jets are observed in both active galactic nuclei (AGNs) and ``microquasars" in our Galaxy. It is believed that these relativistic jets are ejected from the vicinity of black holes. To investigate the formation mechanism of these jets, we have developed a new general relativistic magnetohydrodynamic (GRMHD) code. We report on the basic methods and test calculations to check whether the code reproduces some analytical solutions, such as a standing shock and a Keplerian disk with a steady state infalling corona or with a corona in hydrostatic equilibrium. We then apply the code to the formation of relativistic MHD jets, investigating the dynamics of an accretion disk initially threaded by a uniform poloidal magnetic field in a nonrotating corona (either in a steady state infall or in hydrostatic equilibrium) around a nonrotating black hole. The numerical results show the following: as time goes on, the disk loses angular momentum as a result of magnetic braking and falls into the black hole. The infalling motion of the disk, which is faster than in the nonrelativistic case because of general relativistic effects below 3rS (rS is the Schwarzschild radius), is strongly decelerated around r = 2rS by centrifugal force to form a shock inside the disk. The magnetic field is tightly twisted by the differential rotation, and plasma in the shocked region of the disk is accelerated by the J × B force to form bipolar relativistic jets. In addition, and interior to, this magnetically driven jet, we also found a gas-pressure-driven jet ejected from the shocked region by the gas-pressure force. This two-layered jet structure is formed not only in the hydrostatic corona case but also in the steady state falling corona case.