arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1406.4589astro-ph.SR
收藏

全晕日冕物质抛射：到达地球

Full Halo Coronal Mass Ejections: Arrival at the Earth

Chenglong Shen, Yuming Wang, Zonghao Pan, Bin Miao, Pinzhong Ye, S. Wang

备注：
9 Pages, 9 Figures,Accepted by JGR
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

磁暴主要是由正面的日冕物质抛射（CME）撞击地球，然后与磁层相互作用引起的。然而，并不是所有的正面CME都能撞击地球。因此，哪些日冕物质抛射撞击地球以及何时撞击地球是空间天气研究和预报中的重要问题。在我们以前的工作中（Shen等人，2013），对2007年3月1日至2012年5月31日发生的全晕日冕物质抛射（FHCMEs）的反投影参数进行了估算，其中有39个正面事件可以用GCS模型进行拟合。在这项工作中，我们继续研究这些前侧FHCME（FFHCME）是否以及何时撞击地球。结果表明，这些FFHCME中有59%击中地球，对于传播方向与日地线夹角$ε$小于45 °的中心事件，这一比例增加到75%。在检查了CME的反投影角宽度之后，我们发现所有地球遇到的CME都满足一个简单的标准，即角宽度（$ω$）大于偏离角（$ε$）的两倍。这一结果表明，一些简单的标准可以用来预测CME是否会撞击地球。此外，对于地球遇到的CME，过境时间被发现是大致反相关的去投影速度，但一些事件显着偏离线性。对于速度相近的日冕物质抛射，它们的渡越时间相差可达数天。这种偏差主要是由CME的几何形状和传播方向引起的，这是CME到达预报的关键。

英文摘要：

A geomagnetic storm is mainly caused by a front-side coronal mass ejection (CME) hitting the Earth and then interacting with the magnetosphere. However, not all front-side CMEs can hit the Earth. Thus, which CMEs hit the Earth and when they do so are important issues in the study and forecasting of space weather. In our previous work (Shen et al., 2013), the de-projected parameters of the full-halo coronal mass ejections (FHCMEs) that occurred from 2007 March 1 to 2012 May 31 were estimated, and there are 39 front-side events could be fitted by the GCS model. In this work, we continue to study whether and when these front-side FHCMEs (FFHCMEs) hit the Earth. It is found that 59\% of these FFHCMEs hit the Earth, and for central events, whose deviation angles $ε$, which are the angles between the propagation direction and the Sun-Earth line, are smaller than 45 degrees, the fraction increases to 75\%. After checking the deprojected angular widths of the CMEs, we found that all of the Earth-encountered CMEs satisfy a simple criterion that the angular width ($ω$) is larger than twice the deviation angle ($ε$). This result suggests that some simple criteria can be used to forecast whether a CME could hit the Earth. Furthermore, for Earth-encountered CMEs, the transit time is found to be roughly anti-correlated with the de-projected velocity, but some events significantly deviate from the linearity. For CMEs with similar velocities, the differences of their transit times can be up to several days. Such deviation is further demonstrated to be mainly caused by the CME geometry and propagation direction, which are essential in the forecasting of CME arrival.

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。

↑