近地太阳风性质的源区依赖及其随太阳活动的演化

发布时间：2018-01-06 06:13

本文关键词：近地太阳风性质的源区依赖及其随太阳活动的演化　出处：《山东大学》2017年硕士论文　论文类型：学位论文

【摘要】：太阳风是来自太阳的等离子体流,是影响近地空间环境的重要媒介之一。自1962年宇宙飞船"水手2号"发现太阳风之后,太阳风的来源、初始太阳风的加热和加速机制总是被太阳物理和空间科学领域所讨论。通常将太阳风分为高低速两类,但是并不能单单凭借速度来描述太阳风。在宁静区、活动区和冕洞区等存在的大尺度日冕结构,他们的等离子体的性质和磁场的位型有着明显的区别,而上述差异对不同来源的太阳风会产生何种影响是值得研究的问题。本文主要致力于把近地获得的太阳风特性与其源区类型结合起来,研究其特性的源区依赖及其随其活动的演化特征。该工作可以为不同的太阳风模型提供检验和约束,增进对太阳风来源及初始太阳风的加热和加速机制这一重要问题的理解。我们使用标准的"两步法"(Neugebauer et al.1998,2002),借助于PFSS(Potential Field Source Surface)磁场模型将局地探测的太阳风回溯到太阳表面。然后结合太阳极紫外图像和光球磁场观测数据将足点所处区域分为冕洞区、活动区和宁静区三类(用ch、ar、qs表示)(Fu et al.2015),由此将太阳风划为冕洞风、活动风和宁静风。在上述工作的基础上,本文主要在两个方面开展工作,一是分源区对第22/23和23/24两个太阳活动极小期近地太阳风的性质进行了对比;二是分三个阶段对第23太阳活动周太阳风性质与源区类型的之间的联系进行了研究。已有的研究表明第23/24太阳活动极小期是一个特殊的极小期,此时太阳黑子数目和极区磁通量均明显小于最近的几个极小期(Giuliana et al.2009)。Ulysses卫星的观测表明,第23/24极小期高纬度太阳风性质与22/23极小期存在显著的差异,第22/23太阳活动极小期高纬度太阳风速度、密度、动压均显著的大于第23/24太阳活动周的极小期。我们分源区对黄道面太阳风的研究发现,两个极小期参数的对比与极区存在差异。第23/24极小期冕洞区、宁静区和活动区的太阳风速度均显著大于第22/23极小期,在23/24太阳活动极小期三类太阳风平均速度分别为 524±109km/s、427±112km/s 和 459±110km/s,而在 22/23太阳活动极小期期分别为393±66km/s、366土62km/s和378±47km/s。第23/24极小期近地太阳风密度显著的小于第22/23极小期,第23/24极小期三类太阳风中平均密度分别为 5.0±4.3cm-3、2.7±3.2cm-3和 3.5±2.7cm-3,而 22/23 极小期为10.3±6.3cm-3、10.3±5.8cm-3和7.7±3.6cm-3。两个极小期太阳风中平均磁场相近,冕洞太阳风平均磁场强度最高,较活动区和宁静区太阳风高10%-20%。尤其值得注意的是,两个阶段其来源存在极大的差异,在第22/23太阳活动极小期近地太阳风大部分冕洞区,来自三大区域(ch、ar、qs)太阳风的比例分别是50.3%,13.2和36.5%。而在第23/24活动极小期近地风大部分来源于宁静区,其比例达到69.5%,此时来自其它两大区域(ch、ar)的近地风比例分别是15.9%和14.6%。上述结果表明三类源区的近地太阳风性质在第22/23和23/24太阳活动极小期均存在显著的差异。在第22活动周的极小期有一半以上近地风来自冕洞区域,而第23活动周来自宁静区的风占很大比重(69.5%)。我们认为这与第23太阳活动周太阳表面磁场整体较弱,导致太阳大尺度磁场位型在两个太阳活动极小期存在显著的差异有关。通过分析第23太阳活动周太阳风性质与源区类型的关系,我们发现不同源区太阳风速度、07+/06+和Fe/0的分布存在显著的差异,但是它们分布的区间有有很大一部分是重合的,所以如果仅凭近地太阳风中速度、07+/06+和Fe/0等参数是无法对太阳风进行很好的判别。冕洞风的风速有着双峰分布的现象,其中高速风的峰值和低速风的峰值分别为600km/s和400km/s左右,而这两部分风即高速风和低速风可能来自冕洞的边缘和中心区域。三类太阳风中,其速度和07+/06+都存在反比关系。Fe/0 一般反映低第一电离势的效应,而它的分布一般有四个特征:冕洞风Fe/0的均值明显比活动区风小;随着风速的增加,Fe/0的分布范围和平均值会随之减小;活动区风中Fe/0的分布范围(0.06-0.40,对应的FIP bias为1-7)较冕洞区(0.06-0.20,对应的FIP bias为1-3)大;在这些太阳风中它们的Fe/0的最小是基本都是0.06,FIP bias大约为1,太阳风速度变化时,并不随之改变。以上统计结果可以发现,不同源区初始太阳风加速加热机制十分相似,而不同源区太阳风性质存在差异可能主要由于不同源区磁场强度和磁场位型存在不同。
[Abstract]:The solar wind plasma streaming from the sun, is one of the important media of the space environment. Since 1962, the spacecraft "seaman No. 2" found in the solar wind, the source of the solar wind, the heating of the solar wind and the initial acceleration mechanism is solar physics and space science field are discussed. The solar wind will usually be divided into high speed two class, but not solely relies on speed to describe the solar wind. In the quiet zone of the large-scale structure activity area and coronal hole area, a type of plasma and magnetic properties of them have obvious difference, and the difference of different sources of solar wind will produce what kind of influence is worthy of study. This paper mainly focuses on the characteristics and types of the source region of the solar wind near get together, the evolution characteristics of source region depend on its characteristics and its activities. The work can be different The solar wind model to provide inspection and restraint, promote the heating of the solar wind and the initial source of the solar wind and the important issue of the accelerating mechanism of understanding. The two step we use the standard "(Neugebauer et al.19982002), with the help of PFSS (Potential Field Source Surface) magnetic field model will detect local solar wind back to the sun the surface. Then combined with the solar extreme ultraviolet image and photospheric magnetic field observation data of the foot point area is divided into coronal hole area, activity area and quiet area three (CH, AR, QS) (Fu et al.2015), which will be designated as the coronal hole in the solar wind wind, wind and calm wind activity. Based on the above work, this paper focuses on two aspects, one is the comparative nature of the source region of the 22/23 and 23/24 of the two solar minimum near the solar wind; the two is divided into three stages on the twenty-third week of solar activity and solar wind properties The study was conducted between the source region of the contact type. Studies have shown that the 23/24 solar minimum is a special minimum, the number of sunspots and polar flux were obviously lower than the minimum period of several recent (Giuliana et al.2009) showed that the.Ulysses satellite observation, there are significant differences between the 23/24 minimum high latitude solar wind properties and 22/23 minimum, the 22/23 solar minimum high latitude solar wind velocity, density, dynamic pressure is significantly greater than the minimum 23/24 of the solar cycle. We divide the source region on the ecliptic solar wind, are compared with the polar two minimum parameter differences. The 23/24 minimum coronal hole area, the speed of the solar wind quiet area and activity area were significantly higher than the 22/23 minimum, 23/24 solar minimum three solar wind velocity were 524 + 109km/s, 427 + 112km /s and 459 + 110km/s, and 22/23 in the solar minimum period was 393 + 66km/s, 366 + 47km/s. and 378 62km/s soil 23/24 near minimum solar wind density is significantly less than the 22/23 minimum, the minimum is three 23/24 in the solar wind average density was 5 + 4.3cm-3,2.7 + 3.2cm-3 and 3.5 + 2.7cm-3, 22/23 and the minimum was 10.3 + 6.3cm-3,10.3 + 5.8cm-3 and 7.7 + 3.6cm-3. two minimum average solar wind magnetic field is similar to that of the average magnetic field strength of coronal hole solar wind is the highest, activity area and quiet region of the solar wind with high 10%-20%. in particular, there is a great difference between the two stages in the source. 22/23 solar minimum near the solar wind most of coronal hole region, from three regions (CH, AR, QS) of the solar wind ratio were 50.3%, 13.2 and 36.5%. in the 23/24 minimum wind comes mostly from the quiet zone, the ratio of Cases reached 69.5%, this time from the other two regions (CH, AR) of the near ground wind ratio were 15.9% and 14.6%. the results show that near the solar wind properties of three kinds of source areas there were significant differences in the 22/23 and 23/24 solar minimum. At minimum twenty-second week more than a half wind from the coronal hole region, while the twenty-third week from the quiet region of wind accounted for a large proportion (69.5%). We think this and Zhou Taiyang twenty-third solar surface magnetic field is weak, resulting in large scale solar magnetic fields are related to the existence of significant differences in the two solar minimum. By analyzing the relationship between solar cycle twenty-third solar wind properties the type and source region, we find that the homologous region of the solar wind speed, there are significant differences in the distribution of 07+/06+ and Fe/0, but they have the distribution of the interval is overlapped, so if only near The solar wind velocity, 07+/06+ and Fe/0 parameters is not very good judgement on the solar wind. The wind velocity of coronal holes with the Shuangfeng distribution phenomenon, in which the peak high wind speed and low speed wind peak are respectively 600km/s and 400km/s, and the two part is the wind and the wind speed low speed wind and possible edge from the central region of the coronal hole. Three types of solar wind, its speed and 07+/06+ are inversely related to.Fe/0 generally reflect the effect of low first ionization potential, while its distribution generally has four characteristics: the mean wind is more obvious than Fe/0 coronal hole area of small wind; with the increase of wind speed, and the distribution range of Fe/0 the average value decreases; the wind activity distribution range of Fe/0 (0.06-0.40 FIP bias 1-7, corresponding to a coronal hole region (0.06-0.20), the FIP bias corresponding to 1-3); in the solar wind in their Fe/0 is the basic minimum is 0.06 FIP, about bias 1, the wind speed changes in the sun, is not changed. The results can be found, no homology initial heating mechanism of the solar wind acceleration is very similar, but not the homologous region of solar wind properties are different due to different source regions may be the main magnetic field strength and magnetic field are not the same type.

【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P353.8

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