Differential rotation plays a crucial role in the dynamics of the Sun. We study the solar rotation and its correlation with solar activity by applying a modified machine learning algorithm to identify and track coronal bright points (CBPs) from the Solar Dynamics Observatory/Atmospheric Imaging Assembly observations at 193 Å during cycle 24. For more than 321,440 CBPs, the sidereal and meridional velocities are computed. We find the occurring height of CBPs to be about 5627 km above the photosphere. We obtain a rotational map for the corona by tracking CBPs at the formation height of Fe xii (193 Å) emissions. The equatorial rotation (14.°40 to 14.°54 day⁻¹) and latitudinal gradient of rotation (−3.°0 to −2.°64 day⁻¹) show very slightly positive and negative trends with solar activity (sunspots and flares), respectively. For cycle 24, our investigations show that the northern hemisphere has more differential rotation than the southern hemisphere, confirmed by the asymmetry of the midlatitude rotation parameter. The asymmetry (ranked) of the latitudinal gradient of the rotation parameter is concordant with the sunspot numbers for 7 yr within the 9 yr of the cycle; however, for only 3 yr, it is concordant with the flare index. The minimum horizontal Reynolds stress changes from about −2500 m² s⁻² (corresponding to high activity) in 2012 and 2014 to −100 m² s⁻² (corresponding to low activity) in 2019 over 5° to 35° latitudes within cycle 24. We conclude that the negative horizontal Reynolds stress (momentum transfer toward the Sun’s equator) is a helpful indication of solar activity.

中文翻译：

---

来自 SDO/AIA 观测的第 24 周期太阳自转和活动


差分旋转在太阳的动力学中起着至关重要的作用。我们通过应用改进的机器学习算法来研究太阳自转及其与太阳活动的相关性，以识别和跟踪太阳动力学天文台/大气成像组件第 24 周期期间 193 Å 观测中的日冕亮点 (CBP)。超过 321,440 个 CBP ，计算恒星速度和子午速度。我们发现 CBP 的出现高度约为光球层以上 5627 公里。我们通过跟踪 Fe xii (193 Å) 排放形成高度处的 CBP 获得了日冕的旋转图。赤道自转（14.°40 至 14.°54 天^-1 ）和自转纬度梯度（-3.°0 至 -2.°64 天^-1 ）显示出与太阳活动（太阳黑子）非常轻微的正负趋势和耀斑），分别。对于第24个周期，我们的调查表明，北半球比南半球有更多的差异旋转，中纬度旋转参数的不对称性证实了这一点。自转参数纬度梯度的不对称性（排序）与9年周期内7年的黑子数一致；然而，只有 3 年它与耀斑指数一致。在周期内5°至35°纬度范围内，最小水平雷诺应力从2012年和2014年的约-2500 m ² s ^-2 （对应于高活动）变化至2019年的-100 m ² s ^-2 （对应于低活动） 24. 我们的结论是，负水平雷诺应力（向太阳赤道的动量转移）是太阳活动的有用指示。