太阳暗条形成的观测研究

发布时间：2018-03-18 08:21

本文选题：日珥(暗条)　切入点：暗条形成　出处：《南京大学》2017年博士论文　论文类型：学位论文

【摘要】：太阳暗条是太阳表面悬浮于日冕中的较冷和较高密度的客体。在日面中心时,由于暗条物质吸收了部分太阳光球背景辐射的光,所以呈现为暗色的长条形结构,我们称之为暗条。而当暗条转到日面边缘时,它则表现为明亮的突出发射体,也便是我们日常生活中常常提到的日珥。日珥的形态千奇百怪,有拱状、篱笆状、树丛状、云状和喷流状等等不一而足,其大小,外观以及稳定存在的时间均存在巨大差异。它们往往出现于太阳光球磁场的磁极反转线附近,所以它们常被用作大尺度磁场的示踪物。暗条内物质的温度较周围炽热的日冕低100倍而密度较周围的日冕物质高100倍。基于这些观测事实,许多问题浮现在我们面前:暗条是如何形成的?为何会形成于磁极反转线附近?暗条物质又是从何而来?通过什么手段将物质补充进了暗条中?为此,我们利用美国大熊湖天文台(BBSO)的观测,结合空间望远镜太阳动力学天文台(SDO)和界层光谱成像仪(IRIS)等对两条新形成的活动区暗条进行了分析。通过对暗条物质输运过程、暗条磁场结构和暗条末端足点光谱响应的分析,针对暗条形成这一过程进行了研究。在第一个工作中,我们利用了 BBSO的新太阳望远镜(NST)的观测资料,结合搭载在空间望远镜SDO上的太阳大气成像收集器(AIA)和日震及磁场成像仪(HMI)的观测资料,对2013年6月5日在太阳西南半球的活动区NOAA 11726(西经62度,南纬28度)的一条刚刚形成的活动区暗条进行了研究。我们的观测时间为从16:40:19 UT到17:07:58 UT。我们通过对该暗条的观测,对其形成的模式、双向流的起因和磁场极性进行了分析和判断。首先,我们得到,该暗条通过低层大气发生的磁重联引起的冷物质向暗条通道内抛射来补充物质的方式所形成。这种模式符合之前提出的暗条形成模型中的冷物质抛射模型。这种抛射的物质由低层大气磁重联产生的磁张力来提供初始速度,然后由磁流管内由于足部等离子体加热而引起的气压梯度力维持向上运动,最终从较低的色球层输运到较高的日冕层中。其次,在暗条形成的过程中,我们同时观测到了常被人们提及的暗条物质双向流动的现象。由于双向流动的暗条物质均为单向的流动,因此,我们认为这种双向流动是由朝向不同方向流动的单向流动组成的。这些单向流动则是产生于磁流管足部压力的不平衡。最后,通过使用Chen et al.[33]的判定方法,我们判定这一个暗条应该是一个磁拱支撑的正常极性暗条。我们对暗条的磁场进行无力场外推,发现外推结果同样证实了我们对于暗条极性的判定,说明该方法是一种较为可靠的对暗条的间接判定方法。在第二个工作中,我们分析了 NST观测到的2015年8月21日位于活动区NOAA12403(东经24度,南纬27度)内的一个新形成的暗条,同时还结合了IRIS的观测数据和HMI/SDO的矢量磁图。观测的时间为17:00 UT至19:00 UT。首先,我们通过以下信息确证了该暗条是一个符合冷物质注入模型而形成的活动区暗条:1、物质从暗条末端的强增亮处以30 km/s的高速度抛射进入暗条主轴;2、暗条两侧末端均能观测到连接着向暗条主轴的物质流的增亮,而这些增亮都处于磁极反转线上;3、通过压缩因子的计算确证了暗条末端是为于一个高压缩因子分布的区域,亦即处于QSL处;4、暗条末端处,纤维足点的光谱明显表现出反应磁重联特征的三高斯分量的轮廓。其次,我们通过对暗条整体结构处的压缩因子的计算发现,暗条纤维的足点确切地扎根于QSL中。并且,暗条足点的亮带中可以看到这些足点的增亮并非是连续的一条带状结构,而是有许许多多尺度接近于暗条纤维的细小亮核所组成。这说明磁重联的发生并非是发生于整个QSL处,QSL内部仍然存在着尺度更小的精细结构。再次,我们通过对纤维足点处光谱的分析,首次确证了暗条纤维足点的加热是一种局限于色球中高层过渡区之下的小部分区域的局部加热,足点处磁重联正是发生在太阳大气的这一个层次。最后,我们通过对比NST及IRIS中暗条物质流动的方向,结合非线性无力场外推的磁场结构,确定了暗条中出现的双向流由具有不同流动方向的单向虹吸流动所组成。这种虹吸流的流动方向决定于暗条纤维两个足点的热压力的高低。这是我们首次针对Chen et al.[33]关于双向流的模型给出完整的观测实证。
[Abstract]:The sun is suspended in the surface of the sun in the corona is cold and high density of the object. In the face center, because the filament material absorbs part of the solar photosphere background radiation light, so the show is an elongated structure dark, we call the dark. When a dark day to face edge it is outstanding, the bright emitter, is also often mentioned in our daily life. The morphology of prominence prominence has all sorts of strange things, arch, fence, trees, clouds and jetlike etc. This is not the only one, its size, are great differences exist between appearance and stability when near the reversal. They often appear in the line of the photospheric magnetic field, so it is often used as a tracer of large scale magnetic field. The filament material in the temperature is around 100 times lower hot coronal and coronal mass density is around 100 times higher. Based on these observations. In reality, many problems emerge in front of us: the dark stripe is how it formed? Why is formed near the reversal line? Is a dark matter come from? By what means will be supplemented by a dark matter? Therefore, we use the Big Bear Lake Observatory (BBSO) observations, combined with space solar telescope Dynamics Observatory (SDO) and boundary layer spectral imager (IRIS) on the two newly formed active region filament are analyzed. Based on the mass transport process of filament, filament magnetic field structure and filament end foot spectral response analysis, the needle of filament formation of this process was studied in the first work, we use the BBSO Solar Telescope (NST) observations, combined with solar air collector in the space telescope imaging on SDO (AIA) and helioseismology and magnetic imager (HMI) observations, on June 5, 2013 in the sun Southwest hemisphere active region NOAA 11726 (62 degrees west longitude, latitude 28 degrees) a newly formed active region filament was studied. We observed time from 16:40:19 UT to 17:07:58 UT. we observed by the dark one, the formation of the pattern, causes and the two-way flow field to analyze and judge. First, we get the material, cold filament occurs through the lower atmosphere of the magnetic reconnection caused to the dark passage inside the projectile to supplement the material formed. This pattern is consistent with the formation of a dark cold ejections model proposed before. The magnetic tension of the projectile the material from the lower atmosphere magnetic reconnection generated to provide initial velocity, and then by the magnetic flux tube pressure gradient force due to the foot of the plasma heating to maintain the upward movement from the lower chromosphere corona transport to higher layers. The time, During the formation of the filament, we also observed a dark matter two-way flow is often mentioned as a dark matter. The phenomenon of two-way flow are one-way flow, therefore, we believe that this is a two-way flow of flow in different directions. These groups into a one-way flow of one-way flow is unbalance produced in the magnetic flux tube foot pressure. Finally, by using Chen et al.[33] method, we determined that a filament should be a magnetic arch supported normal polar filament. We of filament magnetic field to field extrapolation, the results show the same extrapolation confirmed our judgement for the filament polarity, indicating that the method is a more reliable of filament indirect method. In the second work, we analyzed the NST observed in August 21, 2015 is located in the active region NOAA12403 (24 degrees east longitude, latitude 27 degrees) In a new form of the dark, but also a combination of magnetic vector graph IRIS observation data and HMI/SDO observations. The time is 17:00 to 19:00 UT UT. first, we adopted the following information confirmed the filament is a cold formed model into the active region filament material: 1. From the end of a dark strong brightening a 30 km/s high speed projectile into filaments spindle; 2, both sides of the filament end was observed by connecting to the dark spindle material flow brightening, and these are brightening the reversal line; 3, through the calculation of compression factor of the filament was the end is in a region of high compression factor distribution, which is QSL; 4, at the end of the filament, fiber spectra show that the three foot Gauss component reaction magnetic reconnection feature contour. Secondly, we through the compression factor of filament structure at the calculation found that the dark A fiber foot exactly rooted in QSL. And the filament foot points of bright band can be seen in the foot points of brightening is not a continuous band structure, but there are many small scale close to the filament fiber light component. This shows that nuclear magnetic reconnection is not in the QSL, QSL still has the fine structure of the smaller scale. Thirdly, we analyze the foot point spectrum of the fiber, the first confirmed local heating of small area heating filament fiber foot is a confined under the transition zone in the high chromosphere, magnetic foot the point is this reconnection occurs in a layer of the solar atmosphere. Finally, we through the dark a comparison of NST and IRIS in the material flow direction, combined with nonlinear extrapolation to magnetic field structure, two-way flow appeared in the dark by having different flow direction to determine the single The siphon flow is composed of siphon flow. The direction of the siphon flow is determined by the thermal pressure of two foot points of the dark fiber. This is the first time for us to give a complete observation of the Chen et al.[33]'s two-way flow model.

【学位授予单位】：南京大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：P182

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