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arXiv 1806.09495astro-ph.SR
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3-冕洞的位相演化I:360°遥感和现场观测

3-Phase Evolution of a Coronal Hole, Part I: 360° remote sensing and in-situ observations

S. G. Heinemann, M. Temmer, S. J. Hofmeister, A. M. Veronig, S. Vennerstroem

摘要:

我们研究了2012年一个观测良好、寿命长、低纬度的冕洞(CH)在10个太阳自转周期内的演化。通过结合来自STEREO-A/B和SDO的EUV图像,我们能够跟踪和研究CH的整个演变,该CH具有连续360 $°$覆盖太阳。利用STEREO-A/B、ACE和WIND卫星对太阳风等离子体和磁场进行了现场测量。从这一点上,我们得到如何不同的进化状态的CH在太阳大气中观察到的(EUV强度和面积的变化)影响相关的高速流在$1$ AU测量的属性。最明显的CH区,三个发展阶段:a)增长,b)最大,和c)衰减阶段。在这些阶段中,CH面积a)在大约三个月的持续时间内从大约$1 \cdot 10^{10} \mathrm{km}^{2}$增加到$6 \cdot 10^{10} \mathrm{km}^{2}$,b)在大约一个月的$> 9 \cdot 10^{10} \mathrm{km}^{2}$中保持相当恒定的面积,和c)在接下来的三个月内最终降低到低于$1 \cdot 10^{10} \mathrm{km}^{2}$,直到CH不能再被识别。这三个阶段也体现在EUV强度和现场测量的太阳风质子体速度。有趣的是,这三个阶段与不同的太阳风速度变化范围有关,我们发现增长阶段的范围为$460-600$ ~km~s $^{-1}$,最大阶段为$600-720$ ~km~s $^{-1}$,而衰减阶段则与$350-550$ ~km~s $^{-1}$的慢和快太阳风速度有关。

英文摘要:

We investigate the evolution of a well-observed, long-lived, low-latitude coronal hole (CH) over 10 solar rotations in the year 2012. By combining EUV imagery from STEREO-A/B and SDO we are able to track and study the entire evolution of the CH having a continuous 360$°$ coverage of the Sun. The remote sensing data are investigated together with in-situ solar wind plasma and magnetic field measurements from STEREO-A/B, ACE and WIND. From this we obtain how different evolutionary states of the CH as observed in the solar atmosphere (changes in EUV intensity and area) affect the properties of the associated high-speed stream measured at $1$AU. Most distinctly pronounced for the CH area, three development phases are derived: a) growing, b) maximum, and c) decaying phase. During these phases the CH area a) increases over a duration of around three months from about $1 \cdot 10^{10} \mathrm{km}^{2}$ to $6 \cdot 10^{10} \mathrm{km}^{2}$, b) keeps a rather constant area for about one month of $> 9 \cdot 10^{10} \mathrm{km}^{2}$, and c) finally decreases in the following three months below $1 \cdot 10^{10} \mathrm{km}^{2}$ until the CH cannot be identified anymore. The three phases manifest themselves also in the EUV intensity and in in-situ measured solar wind proton bulk velocity. Interestingly, the three phases are related to a different range in solar wind speed variations and we find for the growing phase a range of $460-600$~km~s$^{-1}$, for the maximum phase $600-720$~km~s$^{-1}$, and for the decaying phase a more irregular behavior connected to slow and fast solar wind speed of $350-550$~km~s$^{-1}$.

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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