【作者】 崔延美；

【导师】 王华宁；

【作者基本信息】 中国科学院研究生院（国家天文台） ， 天体物理， 2007， 博士

【摘要】 人们以观测的光球磁场为基础,对磁场结构和演化进行了深入的研究。尤其是对和太阳耀斑等活动相关的光球磁场特性进行了比较细致的研究工作。如对太阳光球磁场非势性描述,包括磁场梯度,剪切,电流,磁场无力因子α,电流螺度,磁螺度等;或者构造磁荷或磁偶极等光球下磁源,研究光球上的磁拓扑结构;或者探索磁通量管的浮现和对消现象等。作者在第二章中对此作了较详细的介绍。太阳活动对地球环境有重大的影响。太阳上有各种各样的活动现象,如黑子、耀斑、日珥和日冕物质抛射等。太阳耀斑是日地空间环境的主要扰动源之一。对太阳耀斑现象的认识,物理机制的研究,以及耀斑的预报不仅是理解磁能储存和释放机制的必要手段,也是人们实现空间探索的现实需要。在第三章中,作者对太阳耀斑现象,耀斑模型,耀斑的动力学,耀斑预报等问题作了较细致的概述。太阳耀斑的能量来源于磁场。一般认为,活动区磁场的复杂性和非势性越强,耀斑出现的越频繁。在前人工作的基础上,作者进一步研究和探讨了描述磁场复杂性和非势性的物理量与太阳耀斑的相关性,具体工作如下(详见第四章和第五章):(1)采用1996年4月—2004年1月内MDI/SOHO的全日面纵向磁场数据,选取了包含870个活动区的23990张磁图,耀斑数据是在相应时段内的GOES观测资料。通过对大样本的统计分析,我们得到太阳耀斑产率与纵向磁场最大水平梯度,中性线长度,孤立奇点数目有密切正相关性。同级别的耀斑,产率随时间尺度增加而增大;同一时间尺度内,耀斑级别越低,产率越高。(2)通过分析怀柔1996年1月—2001年8月期间的对应554个活动区的1353张矢量磁图和在相应时段内GOES的耀斑观测资料,采用相同的统计分析方法,我们得到太阳耀斑产率同中性线上的强梯度长度Lg,强剪切长度Ls,强梯度强剪切长度Lgs,和总电流Itot,总电流螺度Htot存在正相关关系。(3)通过分析怀柔的矢量磁图我们还得到,相对Lg与Ls,太阳耀斑产率对Lgs的变化更为敏感。(4)太阳耀斑产率同这几个物理量的正相关关系均可以被Sigmoid函数很好的进行拟合,从而定量的描述了太阳耀斑产率随活动区磁场的非势性和复杂性的增加而增大。(5)纵向磁场最大水平梯度,中性线长度,孤立奇点之间有着较密切的相关关系,有可能有着同样的磁流体力学过程;强梯度和强剪切在中性线上的出现具有很强时间相关性,空间相关性很差。这些研究结果进一步确定了太阳光球磁场与太阳耀斑之间的密切关系。对于利用光球磁场特性进行耀斑预报提供了很好的参考。根据太阳耀斑产率同描述磁场非势性和复杂性的物理特征量间的相关性和Sigmoid拟合函数,我们能够利用这些物理量估计活动区在未来一定时间内的耀斑发生情况。更多还原

【Abstract】 Based on the observations of solar photospheric magnetic fields, much studieshave been made on the magnetic structures and evolvements, especially on pho-tospheric magnetic properties related to solar eruptive activities such as promi-nences, flares, etc. In Chapter 2, the author focused on introducing these photo-spheric magnetic properties which include magnetic non-potentialities (magneticgradient, shear, current, free factorα, current helicity, magnetic helicity), mag-netic topological structures, and magnetic flux emergence and cancelation.Solar activities have important eflects on the solar-terrestrial space envi-ronment. Solar flares are one of the main disturbing sources. Learning theflare phenomena, studying the flare physical mechanism, and forecasting flaresare necessary not only to understand the magnetic energy storing and releasingmechanism in solar atmosphere but also to carry out space exploration missionsof humanity. In Chapter 3, the author made a detailed introduction on the flarephenomena, the flare models, the dynamics mechanism of flares, and the flareforecasting.It is widely believed that the releasing energy of solar flares comes from themagnetic fields. On the basis of the previous studies, the author made furthereflorts on the correlation between solar photospheric magnetic properties andflares. The main results are as follows:(1) during the time period from April 1996 to January 2004, the 23990 MDI/SOHOfull disk longitudinal magnetograms involving 870 active regions and theflare data observed by the GOES spacecraft are employed. Through astatistical analysis on the relationship of flare productivities with the max-imum horizontal gradient, the length of neutral line, and the number of singular points, several results are obtained: the flare productivity is posi-tively correlated with these three measures; the flare productivity becomeslarger in a longer time window; the higher X-ray class flare productivity isoften smaller than the lower X-ray class flare productivity.(2) during the time period from January 1996 to August 2001, 1353 vectormagnetograms observed at Huairou Solar Observing Station and the flaresdata from GOES spacecraft are used. By the same statistical method,we found that the flare productivity is also correlated with the length ofneutral lines with the strong gradient length Lg, the length of neutral lineswith the strong shear Ls, and the length of neutral lines with the stronggradient and shear Lgs, the total current Itot, and the total current helicityHtot.(3) solar flare productivity is more sensitive to Lgs than to Lg and Ls.(4) the correlation between these magnetic measures (mentioned above) and thesolar flare productivity can be well fitted by the sigmoid function, whichcan quantitatively describes the relationship between solar flares and themagnetic complexities and non-potentialities in active regions.(5) additionally, there are intimate relationships between the maximum horizon-tal gradient, the length of neutral line, and the number of singular points,which may be because they are the same MHD process. In the vicinities ofneutral lines, high gradient and strong shear are roughly coincident in timebut hardly in positions.These results further confirmed that solar flares have intimate relationshipwith magnetic fields, which suggest how to employ solar photospheric magneticfields to forecast flares. Based on the correlation between solar flare produc- tivity and these magnetic measures and the sigmoid fitting functions, the ?areproductivities in active regions can be estimated in the future period of time.更多还原