Large-scale poloidal magnetic field dynamo leads to powerful jets in GRMHD simulations of black hole accretion with toroidal field
Large-scale poloidal magnetic field dynamo leads to powerful jets in GRMHD simulations of black hole accretion with toroidal field
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DOI：
10.1093/mnras/staa955
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发表时间：
2018-09
影响因子：
4.8
通讯作者：
M. Liska;A. Tchekhovskoy;A. Tchekhovskoy;E. Quataert
中科院分区：
文献类型：
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作者：
M. Liska;A. Tchekhovskoy;A. Tchekhovskoy;E. Quataert
吸积黑洞（BH）发射相对论性准直喷流，在光度和质量上跨越数十年，这表明喷流发射机制是普遍的，鲁棒的和无标度的。理论模型和广义相对论磁流体动力学（GRMHD）模拟表明，大尺度极向磁通量是形成喷流的关键因素。然而，它的起源是不确定的，也不知道它是否可以在原地产生或从周围介质中向内拖动。在这里，我们使用GPU加速GRMHD代码h-AMR研究全球三维BH吸积异常高的分辨率更典型的本地剪切盒模拟。我们表明，在径向扩展的吸积盘湍流可以产生大规模的极向磁通量原位，即使从一个纯粹的环形磁场。磁通量在黑洞周围积累，直到它在动力学上变得重要，导致磁制动盘（MAD），并发射比吸积流更强大的相对论射流。喷气功率超过以前的GRMHD环向场模拟的10 000倍。喷流没有表现出明显的扭结或箍缩不稳定性，在距离上加速到γ 10，并遵循与观察到的M87喷流相似的准直轮廓。
Accreting black holes (BHs) launch relativistic collimated jets, across many decades in luminosity and mass, suggesting the jet launching mechanism is universal, robust, and scale-free. Theoretical models and general relativistic magnetohydrodynamic (GRMHD) simulations indicate that the key jet-making ingredient is large-scale poloidal magnetic flux. However, its origin is uncertain, and it is unknown if it can be generated in situ or dragged inward from the ambient medium. Here, we use the GPU-accelerated GRMHD code h-amr to study global 3D BH accretion at unusually high resolutions more typical of local shearing box simulations. We demonstrate that turbulence in a radially extended accretion disc can generate large-scale poloidal magnetic flux in situ, even when starting from a purely toroidal magnetic field. The flux accumulates around the BH till it becomes dynamically important, leads to a magnetically arrested disc (MAD), and launches relativistic jets that are more powerful than the accretion flow. The jet power exceeds that of previous GRMHD toroidal field simulations by a factor of 10 000. The jets do not show significant kink or pinch instabilities, accelerate to γ ∼ 10 over three decades in distance, and follow a collimation profile similar to the observed M87 jet.