论文标题
在高雷诺数处的大规模磁场上的平均场分析
Mean-field analysis on large-scale magnetic fields at high Reynolds numbers
论文作者
论文摘要
太阳磁场包括一个11年的活动周期，以黑子数量为代表。这种太阳磁场的维护可以归因于对流区域中的流体运动，即发电机。这项研究进行了Hotta等人提供的全局太阳发电机模拟的平均场分析。 （2016）。尽管该研究成功地在较高的雷诺数字上产生了相干的大规模磁场，但尚未完全了解该领域维持的详细物理。这项研究通过平均场分析提取α-张量和湍流磁扩散性张量。湍流磁扩散率对高雷诺数的数量显着下降。湍流磁扩散率的下降抑制了大规模场向小型场的能量转化。这意味着湍流磁扩散率的下降有助于维持高雷诺数的大规模磁场。观察到明显的向下湍流抽水。它在大型场的弱相中得到了增强。这项研究提出了一个大规模场的环状反转过程，该过程主要由α效应驱动，并可能是由向下抽水触发的。
Solar magnetic fields comprise an 11-year activity cycle, represented by the number of sunspots. The maintenance of such a solar magnetic field can be attributed to fluid motion in the convection zone, i.e. a dynamo. This study conducts the mean-field analyses of the global solar dynamo simulation presented by Hotta et al. (2016). Although the study succeeds in producing coherent large-scale magnetic fields at high Reynolds numbers, the detailed physics of the maintenance of this field have not been fully understood. This study extracts the alpha-tensor and the turbulent magnetic diffusivity tensor through mean-field analyses. The turbulent magnetic diffusivity exhibits a significant decrease towards high Reynolds numbers. The decrease in the turbulent magnetic diffusivity suppresses the energy conversion of large-scale field to small-scale field. This implies that the decrease in the turbulent magnetic diffusivity contributes to the maintenance of a large-scale magnetic field at high Reynolds numbers. A significant downward turbulent pumping is observed; it is enhanced in the weak phase of the large-scale field. This study proposes a cyclic reversal process of a large-scale field which is dominantly driven by the alpha-effect and is possibly triggered by downward pumping.
