标题： 基于SDO/AIA观测的第24活动周的太阳自转和活动 显示英文标题

标题： Solar rotation and activity for cycle 24 from SDO/AIA observations

摘要： 差速旋转在太阳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识别和追踪太阳动力学观测台/大气成像组件在第24活动周期193 \AA 波段的日冕亮点（CBPs），研究了太阳自转及其与太阳活动的相关性。对于超过321,440个CBPs，计算了恒星自转速度和经向速度。我们发现CBPs的发生高度约为光球上方5627公里。通过追踪Fe {\sc xii}（193 \AA ）发射形成的CBPs，得到了日冕的旋转图。赤道旋转速度（14.$^{\circ}$40至14.$^{\circ}$54天$^{-1}$）和纬度梯度（$ - $3. $^{\circ}$0至$ - $2。 $^{\circ}$64天$^{-1}$）分别显示出与太阳活动（黑子和耀斑）非常微弱的正负趋势。 对于第24活动周，我们的研究表明，北半球的纬度差旋转比南半球更大，这通过中纬度旋转参数的不对称性得到了证实。 旋转参数的纬向梯度的不对称性（按等级划分）在该周期的9年内与黑子数一致了7年；然而，只有3年内，它与耀斑指数一致。 最小水平雷诺应力从 2012 年和 2014 年的约$ - $2500 米$^{2}$秒$^{-2}$（对应于高活动性）下降到 2019 年的$ - $100 米$^{2}$秒$^{-2}$（对应于低活动性），跨越第 24 太阳周期内的 5$^{\circ}$至 35$^{\circ}$纬度。 我们得出结论，负的水平雷诺应力（动量向太阳赤道传输）是太阳活动的一个有益指标。 显示英文摘要

摘要： The 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 \AA\ during cycle 24. For more than 321,440 CBPs, the sidereal and meridional velocities are computed. We find the occurring height of CBPs about 5627 km above the photosphere. We obtain a rotational map for the corona by tracking CBPs at the formation height of Fe\,{\sc xii} (193 \AA) emissions. The equator rotation (14.$^{\circ}$40 to 14.$^{\circ}$54 day$^{-1}$) and latitudinal gradient of rotation ($ - $3.$^{\circ}$0 to $ - $2.$^{\circ}$64 day$^{-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 $ - $2500 m$^{2}$ s$^{-2}$ (corresponding to high activity) in 2012 and 2014 to $ - $100 m$^{2}$ s$^{-2}$ (corresponding to low activity) in 2019 over 5$^{\circ}$ to 35$^{\circ}$ 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.