标题： 太阳活动周期24最大值附近的低纬度日冕洞特征 显示英文标题

标题： Characteristics of Low-Latitude Coronal Holes near the Maximum of Solar cycle 24

摘要： 我们研究了从2011年1月1日至2013年12月31日期间通过SDO/AIA-193滤光片提取的288个低纬度日冕洞的统计特性。 我们分析了典型日冕洞属性（如面积、平均AIA-193强度和平均磁场密度）的分布，日冕洞内SDO/AIA-193强度和磁场的局部分布，以及日冕洞中磁通管的分布。 我们发现所有研究的日冕洞的平均磁场密度为3.0 ± 1.6高斯，不平衡磁通量占49 ± 16%。 日冕洞的平均磁场密度、平均无符号磁场密度以及不平衡磁通量在成对之间具有很强的相关性，相关系数cc > 0.92。 此外，我们发现日冕洞的不平衡磁通量主要集中在磁通管中：日冕洞中38%（81%）的不平衡磁通量来源于仅占日冕洞面积1%（10%）的区域，这些区域集中于磁场强度大于50高斯（10高斯）的磁通管内。 由磁通管推导出的平均磁场密度和不平衡磁通量与整个日冕洞的平均磁场密度和不平衡磁通量高度相关（cc > 0.93）。 这些发现表明日冕洞的整体磁特性受磁通管特性的支配。 显示英文摘要

摘要： We investigate the statistics of 288 low-latitude coronal holes extracted from SDO/AIA-193 filtergrams over the time range 2011/01/01 to 2013/12/31. We analyse the distribution of characteristic coronal hole properties, such as the areas, mean AIA-193 intensities, and mean magnetic field densities, the local distribution of the SDO/AIA-193 intensity and the magnetic field within the coronal holes, and the distribution of magnetic flux tubes in coronal holes. We find that the mean magnetic field density of all coronal holes under study is 3.0 +- 1.6 G, and the percentage of unbalanced magnetic flux is 49 +- 16 %. The mean magnetic field density, the mean unsigned magnetic field density, and the percentage of unbalanced magnetic flux of coronal holes depend strongly pairwise on each other, with correlation coefficients cc > 0.92. Furthermore, we find that the unbalanced magnetic flux of the coronal holes is predominantly concentrated in magnetic flux tubes: 38 % (81 %) of the unbalanced magnetic flux of coronal holes arises from only 1 % (10 %) of the coronal hole area, clustered in magnetic flux tubes with field strengths > 50 G (10 G). The average magnetic field density and the unbalanced magnetic flux derived from the magnetic flux tubes correlate with the mean magnetic field density and the unbalanced magnetic flux of the overall coronal hole (cc > 0.93). These findings give evidence that the overall magnetic characteristics of coronal holes are governed by the characteristics of the magnetic flux tubes.