Blob Formation and Ejection in Coronal Jets due to the Plasmoid and Kelvin–Helmholtz Instabilities
文献类型：期刊论文
| 作者 | Ni,Lei1,2; Zhang,Qing-Min3; Murphy,Nicholas A.4; Lin,Jun1 |
| 刊名 | The Astrophysical Journal
 |
| 出版日期 | 2017-05-19 |
| 卷号 | 841期号:1 |
| 关键词 | instabilities magnetic reconnection magnetohydrodynamics (MHD) methods: numerical Sun: activity |
| ISSN号 | 0004-637X |
| DOI | 10.3847/1538-4357/aa6ffe |
| 英文摘要 | Abstract We perform 2D resistive magnetohydrodynamic simulations of coronal jets driven by flux emergence along the lower boundary. The reconnection layers are susceptible to the formation of blobs that are ejected in the jet. Our simulation with low plasma β (Case I) shows that magnetic islands form easily and propagate upward in the jet. These islands are multithermal and thus are predicted to show up in hot channels (335 ? and 211 ?) and the cool channel (304 ?) in observations by the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory. The islands have maximum temperatures of 8 MK, lifetimes of 120 s, diameters of 6 Mm, and velocities of 200 km s?1. These parameters are similar to the properties of blobs observed in extreme-ultraviolet (EUV) jets by AIA. The Kelvin–Helmholtz instability develops in our simulation with moderately high plasma β (Case II) and leads to the formation of bright vortex-like blobs above the multiple high magnetosonic Mach number regions that appear along the jet. These vortex-like blobs can also be identified in the AIA channels. However, they eventually move downward and disappear after the high magnetosonic Mach number regions disappear. In the lower plasma β case, the lifetime for the jet is shorter, the jet and magnetic islands are formed with higher velocities and temperatures, the current-sheet fragments are more chaotic, and more magnetic islands are generated. Our results show that the plasmoid instability and Kelvin–Helmholtz instability along the jet are both possible causes of the formation of blobs observed at EUV wavelengths. |
| 语种 | 英语 |
| WOS记录号 | IOP:0004-637X-841-1-AA6FFE |
| 出版者 | The American Astronomical Society |
| 源URL | [http://libir.pmo.ac.cn/handle/332002/23771]  |
| 专题 | 中国科学院紫金山天文台 |
| 作者单位 | 1.Yunnan Observatories, Chinese Academy of Sciences, 396 Yangfangwang, Guandu District, Kunming, 650216, China; leini@ynao.ac.cn 2.Center for Astronomical Mega-Science, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing, 100012, China 3.Key Laboratory for Dark Matter and Space Science, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, China 4.Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA |
| 推荐引用方式 GB/T 7714 | Ni,Lei,Zhang,Qing-Min,Murphy,Nicholas A.,et al. Blob Formation and Ejection in Coronal Jets due to the Plasmoid and Kelvin–Helmholtz Instabilities[J]. The Astrophysical Journal,2017,841(1). |
| APA | Ni,Lei,Zhang,Qing-Min,Murphy,Nicholas A.,&Lin,Jun.(2017).Blob Formation and Ejection in Coronal Jets due to the Plasmoid and Kelvin–Helmholtz Instabilities.The Astrophysical Journal,841(1). |
| MLA | Ni,Lei,et al."Blob Formation and Ejection in Coronal Jets due to the Plasmoid and Kelvin–Helmholtz Instabilities".The Astrophysical Journal 841.1(2017). |
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来源：紫金山天文台
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