标题： 太阳活动第24周期的自转和活动来自SDO/AIA观测 显示英文标题

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

摘要： 差分旋转在太阳动力学中起着关键作用。 我们通过应用一种改进的机器学习算法，从太阳动力学观测台/大气成像组件在第24周期期间的193 \AA 观测数据中识别和跟踪日冕明亮点（CBPs），来研究太阳旋转及其与太阳活动的相关性。 对于超过321,440个CBPs，计算了恒星时速度和经向速度。 我们发现CBPs的出现高度约为光球层以上5627公里。 我们通过跟踪Fe {\sc 十二} （193 \AA ）发射的形成高度的日冕明亮点，获得了日冕的旋转图。 赤道旋转（14. $^{\circ}$40到14. $^{\circ}$54天$^{-1}$）和旋转的纬度梯度（$ - $3. $^{\circ}$0 到$ - $2。 $^{\circ}$64 天$^{-1}$) 显示与太阳活动（黑子和耀斑）分别有非常微弱的正负趋势。 对于第24个周期，我们的研究显示，北半球的差分旋转比南半球更多，这由中纬度旋转参数的不对称性所证实。 旋转参数的纬度梯度的不对称性（按等级排列）在周期的9年中有7年与黑子数一致；然而，只有3年与耀斑指数一致。 最小水平雷诺应力从2012年和2014年的约$ - $2500 m$^{2}$ s$^{-2}$（对应高活动性）变化为2019年的$ - $100 m$^{2}$ s$^{-2}$（对应低活动性），在太阳活动周期24期内，纬度范围从5$^{\circ}$到35$^{\circ}$。 我们得出结论，负的水平雷诺应力（动量向太阳赤道的转移）是太阳活动的一个有益指示。 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.