In this work, we present simulations of thin accretion disks around black holes, in order to investigate a mean-field disk dynamo, using our resistive GRMHD code, which is able to produce a large-scale magnetic flux. We consider a weak seed field in an initially thin disk, a background (turbulent) magnetic diffusivity, and the dynamo action itself. A standard quenching mechanism is applied to mitigate an otherwise exponential increase in the magnetic field. Comparison simulations of an initial Fishbone–Moncrief torus suggest that reconnection may provide another quenching mechanism. The dynamo-generated magnetic flux expands from the disk interior into the disk corona, becomes advected by disk accretion, and fills the axial region of the domain. The dynamo leads to an initially rapid increase in magnetic energy and flux, while for later evolutionary stages the growth stabilizes. Accretion toward the black hole depends strongly on the type of magnetic-field structure that develops. The radial field component supports extraction of angular momentum, and thus accretion. It also sets the conditions for launching a disk wind, initially from the inner disk area. When a strong field engulfs the disk, strong winds are launched, predominantly driven by the pressure gradient of the toroidal field. For rotating black holes, we identify a Poynting flux-dominated jet, driven by the Blandford–Znajek mechanism. This axial Poynting flux is advected from the disk, and therefore accumulates at the expense of the flux carried by the disk wind, which is itself regenerated by the disk dynamo.

在这项工作中，我们展示了黑洞周围薄吸积盘的模拟，以研究平均场磁盘发电机，使用我们的电阻 GRMHD 代码，它能够产生大规模的磁通量。我们考虑初始薄盘中的弱种子场、背景（湍流）磁扩散率和发电机作用本身。应用标准的淬灭机制来减轻磁场的指数增长。初始鱼骨-蒙克里夫环面的比较模拟表明，重新连接可能提供另一种淬灭机制。发电机产生的磁通量从磁盘内部扩展到磁盘日冕，通过磁盘吸积成为平流，并填充磁畴的轴向区域。发电机导致磁能和磁通量最初快速增加，而在后来的进化阶段，增长趋于稳定。向黑洞的吸积在很大程度上取决于形成的磁场结构的类型。径向场分量支持角动量的提取，从而支持吸积。它还设置了启动盘风的条件，最初是从内部盘区。当强磁场吞没圆盘时，会产生强风，主要由环形磁场的压力梯度驱动。对于旋转黑洞，我们确定了由 Blandford-Znajek 机制驱动的 Poynting 通量主导射流。该轴向坡印廷通量从圆盘平流，因此以圆盘风携带的通量为代价累积，圆盘风本身由圆盘发电机再生。向黑洞的吸积在很大程度上取决于形成的磁场结构的类型。径向场分量支持角动量的提取，从而支持吸积。它还设置了启动盘风的条件，最初是从内部盘区。当强磁场吞没圆盘时，会产生强风，主要由环形磁场的压力梯度驱动。对于旋转黑洞，我们确定了由 Blandford-Znajek 机制驱动的 Poynting 通量主导射流。该轴向坡印廷通量从圆盘平流，因此以圆盘风携带的通量为代价累积，圆盘风本身由圆盘发电机再生。向黑洞的吸积在很大程度上取决于形成的磁场结构的类型。径向场分量支持角动量的提取，从而支持吸积。它还设置了启动盘风的条件，最初是从内部盘区。当强磁场吞没圆盘时，会产生强风，主要由环形磁场的压力梯度驱动。对于旋转黑洞，我们确定了由 Blandford-Znajek 机制驱动的 Poynting 通量主导射流。该轴向坡印廷通量从圆盘平流，因此以圆盘风携带的通量为代价累积，圆盘风本身由圆盘发电机再生。它还设置了启动盘风的条件，最初是从内部盘区。当强磁场吞没圆盘时，会产生强风，主要由环形磁场的压力梯度驱动。对于旋转黑洞，我们确定了由 Blandford-Znajek 机制驱动的 Poynting 通量主导射流。该轴向坡印廷通量从圆盘平流，因此以圆盘风携带的通量为代价累积，圆盘风本身由圆盘发电机再生。它还设置了启动盘风的条件，最初是从内部盘区。当强磁场吞没圆盘时，会产生强风，主要由环形磁场的压力梯度驱动。对于旋转黑洞，我们确定了由 Blandford-Znajek 机制驱动的 Poynting 通量主导射流。该轴向坡印廷通量从圆盘平流，因此以圆盘风携带的通量为代价累积，圆盘风本身由圆盘发电机再生。