Stealth Coronal Mass Ejections from Active Regions
Stealth Coronal Mass Ejections from Active Regions
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DOI：
10.3847/1538-4357/ab371b
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发表时间：
2019-07
期刊：
影响因子：
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通讯作者：
J. O’Kane;L. Green;D. Long;H. Reid
中科院分区：
文献类型：
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作者：
J. O’Kane;L. Green;D. Long;H. Reid
隐形日冕物质抛射(CME)是指没有明显的低日冕特征的太阳喷发。这些日冕物质抛射的特点是速度较慢，但仍可能对地球产生影响，并影响地球的空间天气。因此，了解支撑这些喷发的科学将极大地提高我们探测并最终预测它们的能力。我们介绍了一项利用先进的图像处理技术分析的两个隐形日冕物质抛射的研究，这些图像处理技术在太阳和日球层天文台、太阳动力学天文台和日地关系天文台航天器上的极端紫外线(EUV)成像器的观测中显示了它们的微弱特征。这些航天器提供的不同观点为同时从上方和侧面研究每一次喷发提供了机会。对于每个事件，极紫外光和磁图观测相结合，揭示了爆发的日冕结构。对于一个事件，观测表明在CME的快速上升阶段之前存在磁通量绳。我们发现，这两次事件都起源于活动区，很可能是由附近的喷发引发的令人同情的日冕物质抛射。我们讨论了每一次隐形CME爆发前发生的物理过程，得出的结论是，这些喷发是CME事件分布的低能量和速度尾巴的一部分，并不是一个明显的现象。
Stealth coronal mass ejections (CMEs) are eruptions from the Sun that have no obvious low coronal signature. These CMEs are characteristically slower events but can still be geoeffective and affect space weather at Earth. Therefore, understanding the science underpinning these eruptions will greatly improve our ability to detect and, eventually, forecast them. We present a study of two stealth CMEs analyzed using advanced image processing techniques that reveal their faint signatures in observations from the extreme-ultraviolet (EUV) imagers on board the Solar and Heliospheric Observatory, Solar Dynamics Observatory, and Solar Terrestrial Relations Observatory spacecraft. The different viewpoints given by these spacecraft provide the opportunity to study each eruption from above and the side contemporaneously. For each event, EUV and magnetogram observations were combined to reveal the coronal structure that erupted. For one event, the observations indicate the presence of a magnetic flux rope before the CME’s fast-rise phase. We found that both events originated in active regions and are likely to be sympathetic CMEs triggered by a nearby eruption. We discuss the physical processes that occurred in the time leading up to the onset of each stealth CME and conclude that these eruptions are part of the low-energy and velocity tail of a distribution of CME events and are not a distinct phenomenon.