太阳耀斑过程中的磁场变化研究

发布时间：2018-04-17 04:13

本文选题：太阳耀斑 + 磁场　；参考：《南京大学》2011年博士论文

【摘要】：太阳耀斑是太阳等离子体大气中磁场自由能的快速释放过程,其涉及到很多复杂的物理现象,包括磁场的快速重联、能量传输、等离子体的不稳定性、高能粒子的加速和传播、耀斑大气辐射和动力学变化、物质的运动和抛射等。另外,耀斑是空间灾害性天气的主要扰动源。因此,对于耀斑过程的研究具有重要的理论和现实意义。本文通过观测分析,对于耀斑的磁场特性以及演变机制进行了研究和探讨,其主要的研究内容如下：第一章中,我们简单介绍了太阳耀斑的研究历史、一般特性和分类情况,对于耀斑的观测研究进行了简单归纳,同时对耀斑的模型以及能量释放和传输过程进行了必要的描述,最后对于太阳耀斑期间的磁场的变化及相关研究以及进展进行较详细的介绍。第二章中,我们利用SOHO/MDI全日面磁图以及夏威夷太阳天文台提供的矢量磁图分析研究了2002年7月26日发生在NOAA 10039和NOAA10044活动区的3个连续的M级耀斑事件,报告了与之关联的突然的磁流变化。我们将活动区划分为一定数量的小矩形区域用以确定与这三个连续耀斑相关联的磁流演变的具体时间。在研究磁流突变时,我们首次分析了磁场突变区域的谱线轮廓。第三章中,我们描述了2005年1月24日发生的X7.1级耀斑在耀斑上升相出现的收缩过程,该耀斑对空间天气产生剧烈的影响而出名。采用Low (1982)提出的非线性无力场模型以及将线性无力场外推至复杂活动区的方法,我们定量地描述了在任意给出的位置,剪切极小的磁环具有较小的高度和水平尺度。这个结论验证了磁能释放导致的太阳日冕中剪切磁环的分解过程伴随着耀斑环的收缩。第四章中,我们利用多波段资料分析了2005年1月15日发生在NOAA 10720活动区的一个X2.6耀斑事件,介绍了该耀斑的几个特性：耀斑开始前出现Hα远区增亮；耀斑带的分离运动呈现前慢后快两个阶段,而且硬X射线增亮发生在耀斑带的快速分离阶段；磁中性线附近出现快速的横向磁场增强。这几个特性均支持类似耀斑tether-cutting模型所提出的两步重联的思路：耀斑能量释放开始于核心区域的两个不同系统的剪切磁环重联,该重联形成长的爆发磁绳,拉升上面的日冕磁力线引起第二步的重联。最后对本文的工作做了一个总结并对后续工作进行了展望。
[Abstract]:Solar flare is a rapid release process of magnetic field free energy in the atmosphere of solar plasma. It involves many complicated physical phenomena, including the fast reconnection of magnetic field, energy transmission, the instability of plasma, the acceleration and propagation of high-energy particles.Flares of atmospheric radiation and dynamics, motion and ejection of matter, etc.In addition, flare is the main disturbance source of space disastrous weather.Therefore, the study of flare process has important theoretical and practical significance.Through observation and analysis, the magnetic field characteristics and evolution mechanism of flares are studied and discussed in this paper. The main research contents are as follows:In the first chapter, we briefly introduce the history, general characteristics and classification of solar flares, summarize the observation of flares, and describe the model of flares and the process of energy release and transmission.Finally, the variation of magnetic field during solar flare and the related research and progress are introduced in detail.In the second chapter, we study three continuous M-class flare events in the active regions of NOAA 10039 and NOAA10044 on July 26, 2002 by using the SOHO/MDI all-solar magnetic map and the vector magnetic map provided by the Hawaii Solar Observatory.A sudden flux change associated with it is reported.The active region is divided into a certain number of small rectangular regions to determine the specific time of flux evolution associated with these three continuous flares.In the study of magnetic flux mutations, the spectral profile of the magnetic field abrupt region is analyzed for the first time.In the third chapter, we describe the contraction process of the X7.1 flare in the rising phase of the flare, which is famous for its severe influence on the space weather.Using the nonlinear force field model proposed by Low (1982) and the method of extrapolating the linear force field to the complex active region, we quantitatively describe the small height and horizontal scale of the magnetic ring with minimal shear at any given position.This conclusion verifies that the decomposition of shearing rings in the solar corona due to the release of magnetic energy is accompanied by the contraction of the flare rings.In chapter 4, we analyze an X2.6 flare event in the NOAA 10720 active region on January 15, 2005 using multi-band data, and introduce several characteristics of the flare: h 伪 far area brightness appears before the flare starts;The separation motion of flare zone shows two stages before and after slow and fast, and hard X-ray enhancement occurs in the fast separation phase of flare zone, and a fast transverse magnetic field enhancement occurs near the magnetic neutral line.These characteristics all support the idea of two-step reconnection similar to the one proposed by the flare tether-cutting model: the flare energy release begins with the shear ring reconnection of two different systems in the core region, and the reconnection forms a long burst magnetic rope.Pulling up the coronal magnetic field above causes the second step to reconnect.Finally, a summary of the work of this paper is made and the future work is prospected.
【学位授予单位】：南京大学
【学位级别】：博士
【学位授予年份】：2011
【分类号】：P182.52

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