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arXiv 1906.01757astro-ph.SR
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短暂冕洞的特征

Characteristics of ephemeral coronal holes

Andrew R. Inglis, Rachel E. O'Connor, W. Dean Pesnell, Michael S. Kirk, Nishu Karna

摘要:

小规模的短暂冕洞可能是太阳盘面上经常出现的特徴,但相对而言很少受到注意。这些事件的特点是结构紧凑,总寿命短,大大小于太阳圆盘穿越。我们提出了一个系统的搜索这些事件,使用大气成像组件EUV图像数据从太阳动力学天文台,覆盖时间段2010 - 2015。根据严格的标准,这次搜索产生了四个短暂冕洞现象的明显例子。每个事件的属性的特点,包括他们的总寿命,增长和衰减率,和地区。这些事件的磁性也确定使用日震和磁成像仪数据。基于这四个事件,短暂的冕洞经历了高达3000 Mm 2/hr的快速初始增长,而衰变阶段通常更为渐进。像传统的冕洞一样,每个短暂冕洞中的平均磁场显示出一致的极性,平均磁通量密度通常< 10 G。在1天文单位的太阳风数据中没有发现相应的特征。还需要进一步的研究来确定短暂的冕洞是被低估的事件还是真正罕见的现象。

英文摘要:

Small-scale ephemeral coronal holes may be a recurring feature on the solar disk, but have received comparatively little attention. These events are characterized by compact structure and short total lifetimes, substantially less than a solar disk crossing. We present a systematic search for these events, using Atmospheric Imaging Assembly EUV image data from the Solar Dynamics Observatory, covering the time period 2010 - 2015. Following strict criteria, this search yielded four clear examples of the ephemeral coronal hole phenomenon. The properties of each event are characterized, including their total lifetime, growth and decay rates, and areas. The magnetic properties of these events are also determined using Helioseismic and Magnetic Imager data. Based on these four events, ephemeral coronal holes experience rapid initial growth of up to 3000 Mm2/hr, while the decay phases are typically more gradual. Like conventional coronal holes, the mean magnetic field in each ephemeral coronal hole displays a consistent polarity, with mean magnetic flux densities generally < 10 G. No evidence of a corresponding signature is seen in solar wind data at 1 AU. Further study is needed to determine whether ephemeral coronal holes are under-reported events or a truly rare phenomenon.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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