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arXiv 1901.01404astro-ph.HE
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吸积-喷射流中磁通量的产生和输运

Generation and transport of magnetic flux in accretion-ejection flows

Ioannis Contopoulos

摘要:

天体物理吸积流与辐射和外流(风和喷流)的高能发射有关。这两个过程在X射线双星爆发的广泛观测是可用的。然而,对它们的动态仍然难以令人信服地理解。控制动力学的主要因素被认为是一个大规模的磁场,线程系统。我们建议,在静止状态下,该领域举行的地方通过吸积物质向内平流和向外扩散之间的微妙平衡。我们还提出,该领域的来源是一个不断增长的环形电流所产生的畸变辐射压力的最内部的等离子体电子在轨道上围绕中央黑洞。这就是宇宙电池的天体物理机制。当环形电流外的返回磁场通过周围的盘扩散时,盘磁场及其相关的吸积率逐渐增加,从而导致系统爆发。当中心吸积流与辐射接近均分时,它被破坏,宇宙电池停止运作。向外的场扩散于是被逆转,磁通量与聚集在中心黑洞周围的磁通量重新连接并消失。磁场和相关的吸积速率缓慢下降,系统逐渐被驱动回到静止状态。我们的结论是,宇宙电池的行动(或不行动)可能是丢失的关键,将使我们能够了解天体物理吸积-喷射流的长期演变。

英文摘要:

Astrophysical accretion flows are associated with energetic emission of radiation and outflows (winds and jets). Extensive observations of these two processes in X-ray binary outbursts are available. A convincing understanding of their dynamics remains, however, elusive. The main agent that controls the dynamics is believed to be a large scale magnetic field that threads the system. We propose that during the quiescent state, the field is held in place by a delicate balance between inward advection and outward diffusion through the accreting matter. We also propose that the source of the field is a growing toroidal electric current generated by the aberrated radiation pressure on the innermost plasma electrons in orbit around the central black hole. This is the astrophysical mechanism of the Cosmic Battery. When the return magnetic field outside the toroidal electric current diffuses through the surrounding disk, the disk magnetic field and its associated accretion rate gradually increase, thus leading the system to an outburst. After the central accretion flow approaches equipartition with radiation, it is disrupted, and the Cosmic Battery ceases to operate. The outward field diffusion is then reversed, magnetic flux reconnects with the flux accumulated around the central black hole and disappears. The magnetic field and the associated accretion rate slowly decrease, and the system is gradualy driven back to quiescence. We conclude that the action (or inaction) of the Cosmic Battery may be the missing key that will allow us to understand the long-term evolution of astrophysical accretion-ejection flows.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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