基于源区位置统计结果的日冕物质抛射观测特征研究

发布时间：2018-03-13 10:51

本文选题：日冕物质抛射　切入点：活动区　出处：《中国科学技术大学》2011年博士论文　论文类型：学位论文

【摘要】：日冕物质抛射(Coronal Mass Ejection, CME)是太阳上最猛烈的爆发活动之一,是引起行星际空间和地磁扰动的主要原因。现在常用白光日冕仪的观测来研究日冕物质抛射的传输和演化过程,因而如何恰当地理解白光日冕仪中的CME的观测特征对太阳和空间物理领域的许多相关研究至关重要。另外,活动区储存了大量的磁自由能,被认为是CME的有力产生者。深入地研究CME与活动区之间的关系,对了解CME的触发机制和产生规律十分重要。为了避免数据选取过程中人为因素引起的偏差,在研究过程中,我们尽量保持了CME和活动区样本的完整性,对CDAW CME目录’列出的1997-1998年间所有1078个CME的源区位置进行了认证。我们发现除了因数据质量差而未能认证源区位置的231个CME外,总共有288个(34%)CME的源区在太阳正面、234个(28%)CME的源区在太阳的边缘以及325个(38%)CME在EIT195A观测中没有明显爆发特征。同时在SOHO/MDI综合磁图的基础上,应用Wang and Zhang于2008年发展的活动区自动识别及参数提取法,对该时期内的活动区进行了识别,总共得到108个MDI活动区。结合CME源区位置信息,我们发现53%的活动区产生了CME,且其中约14%的活动区为CME多产的活动区(产生3个及以上CME),另一方面63%的CME产生于活动区,其它的CME则产生于活动区外。在此基础上,统计分析了1997-1998年间LASCO CME的观测特征及其与活动区的关系,其中包括CME源区位置的分布、与CME亮度相关的若干科学问题、CME在内日冕中的偏转以及CME与活动区的关系等,获得了以下有意义的结果。 1.CME源区位置分布方面： CME源区位置的纬度分布呈现明显的双峰,峰值出现在±(15°-30°),这恰好与太阳活动区带的位置相吻合,而且没有CME产生于极区(±75°以外)；观测到的CME中大约有56%产生于靠近太阳边缘的区域；CME的平均表观速度约为435km s-1,并且靠近日面中心的和边缘CME的表观速度分布没有明显的差别；边缘CME的平均角宽度约为59°,其中约有65%的边缘CME的角宽度在30°到90°之间；统计结果显示靠近日面中心的CME的平均角宽度是边缘CME的两倍,这表明存在明显的投影效应。 2.与CME亮度相关的若干科学问题方面： (1)大约有32%的太阳正面的CME无法被SOHO观测到,这可能是地磁暴的高漏报率的一个直观的解释。 (2)白光CME在任意给定日心距离处的亮度与其速度大致上正相关,这可能表明白光日冕仪中增强的亮度不仅包含CME的贡献还包含周围压缩的太阳风等离子体的贡献；由白光日冕仪中亮度得到的CME质量可能是高估了。 (3)投影效应和能量的剧烈释放是晕状CME的主要原因,但对边缘晕状CME来说,后者更为主要；总体上,大约有25%的晕状CME强于所有CME的平均强度。 3.CME在内日冕中的偏转方面：统计结果表明,在接近太阳活动低年期间,大多数CME向赤道方向偏转。根据CME偏转过程的不同特征,可以把CME向赤道方向的偏转分为不对称膨胀、非径向抛射以及偏转传播三类。 4.在CME与活动区的关系方面： (1)活动区的CME产生率与活动区的复杂程度相关性很强,但与活动区所处的阶段无关。能产生CME的活动区的面积、磁通量、极性反转线的长度和条数的平均值是没有产生CME的活动区的2倍左右,而CME多产的活动区的参数平均值更大一些。 (2)同源相关的CME产生的时间间隔约为8小时,这可能反映了在同一活动区内一个CME触发另一个CME或者同一活动区积累磁自由能的时间尺度。 (3)同一个活动区在15小时时间内最多只能产生一个强的(速度在800 kms-1以上)CME。 (4)CME的表观参数,如速度、加速度、角宽度等与CME是否来自活动区没有明显的关系。另外,统计表明CME的表观速度与活动区参数之间没有明显的关系,而CME的角宽度与活动区参数存在较弱的相关性(相关系数为0.45),其中活动区的面积和磁通量是两个重要的因素。
[Abstract]:Coronal mass ejections (Coronal Mass, Ejection, CME) is one of the most violent eruptions on the sun, is the main cause of disturbance in the interplanetary space and geomagnetic. Transmission and evolution is now commonly used in white light coronagraph observations of CMES, so how to properly understand the observational characteristics of white light coronagraph in CME for solar and space physics and many related research is very important. In addition, the magnetic storage area a large number of free energy, is considered a powerful producer of CME. Further study on the relationship between CME and activity area, is very important for understanding the CME trigger mechanism and rules.
In order to avoid the error caused by human factors in the process of data selection, in the course of the study, we try to keep the integrity of the sample CME and activity area, source position on the CDAW CME directory "listed 1997-1998 years all 1078 CME were certified. We found that because of poor data quality and 231 failed to CME certification the location of the source area, a total of 288 (34%) CME source areas in front of the sun, 234 (28%) CME source region on the edge of the sun and 325 (38%) CME in EIT195A in the observation of no obvious outbreak characteristics. Based on SOHO/MDI integrated magnetic map on the application of Wang and Zhang automatic recognition and parameter region in 2008 for the development of extraction of activity area of the period were identified, for a total of 108 MDI active region. According to CME source location information, we found that 53% of the active regions produced CME, and about 14% of its activity area For the CME prolific activity area (3 and more CME), 63% of the CME is produced in the active area, and the other CME is produced outside the active area.
Based on the statistical analysis of the observational characteristics of 1997-1998 LASCO CME and its relationship with the region, including the CME source distribution area, some scientific issues related to the brightness of CME, CME, and CME and deflection in the corona area relationship, get some meaningful results.
1.CME source area location distribution:
The latitude distribution of CME source zone showed obvious peak in Shuangfeng, + (15 -30), which coincided with the solar activity zone coincides with the position, and there is no CME produced in the region (other than + 75 degrees); observed CME in about 56% in the region near the edge of the sun. Table CME view; the average speed is about 435km s-1, there was no significant difference between the values of velocity distribution on the surface and near the center and the edge of the CME table; the average width of the edge of the CME angle is about 59 degrees angle width, of which about 65% of the CME edge at 30 degrees to 90 degrees; the statistical results showed by the average angle of the center of the surface recently CME is two times the width of the edge of the CME, which indicates the existence of projection effect is obvious.
2. a number of scientific issues related to CME luminance:
(1) about 32% of the sun's CME can not be observed by the SOHO, which may be an intuitive explanation of the high leakage rate of geomagnetic storms.
(2) white CME in any heliocentric distance brightness is roughly positively correlated with its speed, which may indicate that the enhanced brightness light coronagraph in CME contains not only the contribution of the solar wind plasma also contains around compression contribution; obtained by brightness white light coronagraph in CME quality may be overestimated.
(3) projection effect and severe energy release are the main causes of halo CME, but for the halo CME, the latter is more important. In general, about 25% of halo CME is stronger than the average intensity of all CME.
3.CME's deflection in the inner Corona:
The statistical results show that most of the CME are deflected towards the equator during the low solar activity. According to the different characteristics of CME deflection process, the deflection of CME to the equator can be divided into three categories: asymmetric expansion, non radial projection and deflection propagation.
4. in terms of the relationship between CME and the active area:
(1) the complexity of correlation zone CME generation rates and activity area is very strong, but has nothing to do with the activity stage. Activity area can produce CME area, magnetic flux, average length and the number of the polarity inversion line is about 2 times the activity area did not produce CME. While the average value of the parameters, the active region CME's prolific large number.
(2) the time interval of homologous CME generation is about 8 hours, which may reflect the time scale of CME's accumulation of magnetic free energy in another CME or the same activity area in the same activity area.
(3) the same active area can only produce a strong (speed over 800 kms-1) CME. at most in 15 hours
(4) CME table view parameters, such as velocity, acceleration, angular width and whether CME from the active region no obvious relationship. In addition, the statistics showed that there was no obvious relationship between CME apparent velocity and area parameters, and the angular width and area parameters of CME are related to weak (related coefficient of 0.45), and the area and magnetic flux are two important factors.

【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2011
【分类号】：P182.62

【共引文献】