| 中文题名： | 太阳迷你暗条的形成与爆发机制研究 |
| 姓名： | |
| 保密级别： | 公开 |
| 论文语种： | 中文 |
| 学科代码： | 070401 |
| 学科专业： | |
| 学生类型： | 学士 |
| 学位： | 理学学士 |
| 学位年度： | 2021 |
| 学校： | 北京师范大学 |
| 校区： | |
| 学院： | |
| 第一导师姓名： | |
| 第一导师单位： | |
| 第二导师姓名： | |
| 提交日期： | 2021-05-30 |
| 答辩日期： | 2021-05-13 |
| 外文题名： | A Study about How Solar Mini-filaments Form and Erupt |
| 中文关键词： | |
| 外文关键词： | sun ; filament ; sun corona ; sun magnetic field ; sun coronal jets |
| 中文摘要： |
太阳暗条是日冕中由磁场束缚的较冷的致密客体，由于通常表征日冕中的非势磁场结构，因此随着磁自由能的释放，容易发生爆发现象，并造成太阳风暴以及后续各种空间天气响应，影响地球的空间环境。长期以来，人们的目光主要聚焦在较大尺度的暗条上，而对尺度较小的迷你暗条的研究相对较少。这一方面是因为以往的观测手段在迷你暗条这么小的尺度很难有足够的分辨率，另一方面则缘于难以在如此小的尺度以及弱场条件下外推得到迷你暗条对应的日冕磁场。本文聚焦美国大熊湖天文台的GST望远镜在Hα波段所观测到的一个迷你暗条，综合光球磁场、极紫外波段图像，分析了其从形成到爆发的过程，并第一次在如此小的尺度上利用磁通量绳插入法重构出了爆发前暗条的磁场结构，探讨了该暗条爆发的触发机制。本次观测的迷你暗条与日冕喷流同时出现，综合磁场重构结果，我们对迷你暗条形成与日冕喷流间的关系进行了探讨。随后，发生于暗条南侧足根部的汇聚运动所导致的磁对消使暗条大部分磁场连接到更大尺度磁场中，造成了失败的暗条爆发。本研究证明了在10角秒之小的尺度上进行磁场重构的可行性，鼓励后续研究使用磁通量绳插入法重构迷你暗条磁场。研究结果显示，日冕喷流与迷你暗条爆发都与磁对消密切相关，我们对其具体形成机理进行了讨论。另外，正如我们研究的这个暗条，我们发现有些迷你暗条的爆发并不一定由理想磁流体力学不稳定性触发，而是由暗条主体磁场在足点处的磁对消触发。由于光球磁对消的可预测性，我们可以提前预报不稳定大尺度结构附近的小尺度爆发，从而提高大尺度爆发预报的准确性。
﹀
|
| 外文摘要： |
Solar filaments are cold and dense plasma structures confined by magnetic fields in the solar corona. They often appear as the symbol of non-potential fields of the corona, so as a result of magnetic free energy release, they can erupt and cause solar storms and severe space weather. For a long time, scientists mainly focus on relatively large-scale filaments, and small-scale mini-filaments lack the attention of researchers. This is due to the low resolutions of ground-based solar telescopes, and the difficulty of extrapolating the coronal magnetic field in such a small-scale, weak-field condition. In this study, we focus on a mini-filament observed in the Hα band by GST at the Big Bear Solar Observatory, and analyze the whole process of its formation and eruption with photosphere magnetogram and EUV images as references. We also re-constructed its magnetic field using flux rope insertion method, which is helpful for understanding the magnetic field configuration before eruption and the trigger of eruption. We find that the formation of the mini-filament coincides with a coronal jet at its south end. Together with the coronal magnetic field re-construction results, we analyze the relationship between filament formation and coronal jet. Then the magnetic cancelation at the south end caused by converging motions reconnects the filament field with a larger field, and causes the failed eruption of the filament. This mini-filament is under a large-scale quiescent filament, and its eruption gives obvious disturbance to the overlying filament. This study proves the coronal field re-construction is still possible in a scale as small as 10 arcsecs, and encourages the upcoming researches to analyze mini-filaments using flux rope insertion method. Our results show that coronal jets are likely to be triggered by magnetic cancelation, and that the formation of mini-filaments may be the result of chromospheric heating caused by nearby magnetic cancelation. Besides, as the mini-filament studied in this research, the eruption of mini-filaments can be triggered by magnetic cancelation at one of its ends, instead of ideal MHD instabilities. As the photospheric magnetic cancelation can be forecasted at a relatively accurate level, we can foresee the small scale eruption near the unstable large-scale structures, and consequently improve the forecasting accuracy of major erupts.
﹀
|
| 参考文献总数： | 38 |
| 插图总数： | 20 |
| 插表总数： | 0 |
| 馆藏号： | 本070401/21021 |
| 开放日期： | 2022-05-30 |
谷歌
