色球磁场极性反转结构的某些观测特征

利用怀柔太阳观测站的３００余对球和色球的观测磁图，分析得出色球极性反转结构是存在于太阳大气中的真实物理现象的结论，根据对活动区两个层次上的磁场精细结构的分析，发现球磁场反转结构可能有４种不的存在形式。     

晚型矮星的色球活动

晚型矮星色球ＣａⅡＨ和Ｋ级及Ｈα线发射的波动的时序分析，能提供我们关于恒星活动的许多信息。在晚型矮星上都观测到类似太阳色球活动行为的所有时标变化。在类太阳恒星上找到了类太阳的＂Ｍａｕｎｄｅｒ极小”长期宁静统计意义上的证据；在晚型矮星上完全肯定地观测到十年左右周期的；已用几天到几星期时标的色球活动区的自转调制来测量晚型星的自转周期；在若干晚型星上也已发现几分钟到几小时时标的类耀发现象。     

太阳耀斑的光球磁场和色球速度场观测

太阳磁场望远镜安装了CCD图象接收处理系统后,得到许多精细结构的两维、实时磁场、速度场图。本文对其中观测的两群黑子,做耀斑磁场、速度场分析。在此基础上指出,异极性磁区相互渗透是普遍存在的,耀斑亮核均发生在异极性磁区相互挤压的前锋。这就为挤压无力场耀斑模式提供了有力的证据。同时发现,在耀斑发生的区域,流场的方向是向下的。     

全日面磁场观测资料的初步处理

用口径为１０ｃｍ的全日面磁场望远镜，我们获得了光球的全日面视向磁场观测资料，与３５ｃｍ磁场望远镜的观测结果比对，发现日面上各活动区磁场的形态以及强度都吻合较好，说明全日面磁场望远镜得到的观测资料是可信的。     

类太阳色球活动星εEri磁场的观测研究

本文给出１９９３—１９９４年期间，用云南天文台１米望远镜折轴摄谱仪观测获得类太阳色球活动星。εＥｒｉ的５个波段高分辨、高信噪比光谱，运用两种不同方法：谱线轮廓塞曼致宽分析和多重线统计分析法成功地测定了εＥｒｉ的表面磁场强度和磁场的覆盖因子，并对这两种磁场测定方法作了简单的讨论．     

2009年7月22日昆明日偏食太阳色球观测

阐述了云南天文台太阳全日面Hα色球望远镜对特殊天象日食的观测及资料情况。同时为局部射电源特征分析研究、CME理论、地球物理效应等相关学科研究提供资料共享信息。     

2004年6月8日金星凌日Hα色球观测

介绍了2004年6月8日云南天文台全日面Hα色球望远镜观测金星凌日的情况，以及对太阳色球活动的监测，并直接给出不同时刻金星在太阳球面的投影和金星的实时图像资料。金星凌日时，Hα色球活动区均未发生耀斑爆发及其它伴随现象。整个凌日过程金星没有掩盖活动区。     

色球和日冕的MHD加热机制

扼要地介绍了色球和日冕加热问题的研究历史。随着空间太阳观测技术的进步，人们认识到色球和日冕加热机制主要与MHD过程有关。因此，在本文中着重介绍四种MHD色球和日冕加热机制：（1）阿尔芬波；（2）MHD湍动；（3）场向电流；（4）磁重联。由于这四种加热机制的有效性都需要通过高分辨率观测来判定，所以空间太阳观测对于研究色球和日冕加热问题具有重大意义。     

黑子半影内偶极运动磁特征的Hinode观测研究

利用Hinode卫星观测的单色像和磁图,对出现在黑子半影内的35对偶极运动磁特征进行形态特征、运动速度以及低层太阳大气响应3方面的研究,得出以下结论:(1)偶极运动磁特征正负两极成对出现在黑子半影较垂直的磁场之间并向着半影外边界运动,间接验证了偶极运动磁特征起源于黑子半影水平磁场,在2-8小时的时间间隔内,同一位置上会反复出现形态特征和运动速度相似的偶极运动磁特征,为海蛇状磁力线模型提供了证据支持. (2)光球和色球在偶极运动磁特征向外运动过程中会出现增亮,说明偶极运动磁特征会加热中低层太阳大气.(3)偶极运动磁特征的出现位置和半影磁场结构分布符合非梳子状黑子半影结构特征.     

太阳磁场的观测

分析了太阳的观测磁图所涉及的磁场位形 ,以及磁场观测研究中的一些问题。     

The Hβ Chromospheric Magnetic Field in a Quiescent Filament

We observed the line-of-sight magnetic field in the chromosphereand photosphere of a large quiescent filament on the solar disk on September 6, 2001 using the Solar Magnetic Field Telescope in Huairou Solar Observing Station. The chromospheric and photospheric magnetograms together with Hβ filtergrams of the filament were examined. The filament was located on the neutral line of the large scale longitudinal magnetic field in the photosphere and the chromosphere. The lateral feet of the filament were found to be related to magnetic structures with opposite polarities. Two small lateral feet are linked to weak parasitic polarity. There is a negative magnetic structure in the photosphere under a break of the filament. At the location corresponding to the filament in the chromospheric magnetograms, the magnetic strength is found to be about 40-70 Gauss (measuring error about 39 Gauss). The magnetic signal indicates the amplitude and orientation of the internal magnetic field in the filament. We discuss several possible causes which may produce such a measured signal. A twisted magnetic configuration inside the filament is suggested .     

The Fundamental Parameters, Chromospheric Activity and Magnetic Field Measurements of Hr 5553

The CCD echelle spectra of the chromospherically active binary HR 5553 are obtained using the 2.16 m telescope with Coudé echelle spectrograph of Beijing Observatory in April 1996. The features of Ca II H & K, Hα, He I D3 and Ca II IRT2 (λ 8542 AA) & IRT3 (λ 8662 AA) are presented. The absolute fluxes of these lines which provide the useful information to study the chromospheric activity of HR 5553 are given. The fundamental parameters of the cool dwarf component of HR 5553 are determined using the analysis of the observed spectra with a resolution of R ≃ 60000 and signal-to-noise ratio S/N = 100 ∼ 300. A detailed spectroscopic analysis has yielded the following fundamental parameters: Effective temperature: Teff = 4881 K Surface gravity: log(g) = 3.65 Logarithmic iron abundance: [Fe/H] = –0.30 as well as that of other 12 metal elements (relative to the Sun) are listed in the Table II and Table III. Microturbulence: ζ = 1.20 km s-1. Magnetic field measurements of the cool dwarf component of HR 5553 have been made using the Stenflo-Lindegren statistical analysis and the profile-addition technique. The magnetic field strength and filling factor are obtained. This revised version was published online in July 2006 with corrections to the Cover Date.     

Observational evidence for various models of Moving Magnetic Features

We present new measurements of Moving Magnetic Features (MMFs) based on the observations of the active region NOAA 5612 made at Big Bear Solar Observatory (BBSO) on 2 August, 1989. We check the existing theoretical models against our new observations and discuss the origin of MMFs conjectured from the deduced observational constraints.     

Features of the Martian Magnetic Field Structure

Based on the single-fluid MHD model of Mars space simulation, this paper has studied the magnetic field structure in the near-Mars space and investigated the influence of Martian crustal magnetic anomalies on the magnetic field structure. In the process of the solar wind interaction with Mars, the bow shock and magnetic pile-up region are produced. The interplanetary magnetic lines are curved and deformed while they are towed toward the two poles by the solar wind. The majority of magnetic lines bypass the two poles, then leave behind a ‘V-shaped’ structure in the magnetotail behind Mars. In the crust of Mars, the local magnetic anomalies have a noticeable influence on the magnetic field structure. The magnetic anomalies at different positions and in different intensities interact with the solar wind to form the mini-magnetospheres of different structures and morphologies, such as the towed mini-magnetosphere and the mini-magnetosphere with open magnetic lines. The local magnetic anomalies have changed the near-Mars magnetic field structure, and probably changed the plasma distribution as well.     

The Magnetic Field Effect on Planetary Nebulae

In our previous work on the 3-dimensional dynamical structure of planetary nebulae the effect of magnetic field was not considered. Recently Jordan et al. have directly detected magnetic fields in the central stars of some planetary nebulae. This discovery supports the hypothesis that the non-spherical shape of most planetary nebulae is caused by magnetic fields in AGB stars. In this study we focus on the role of initially weak toroidal magnetic fields embedded in a stellar wind in altering the shape of the PN. We found that magnetic pressure is probably influential on the observed shape of most PNe.     

宇宙磁场中的中微子

本文讨论了有质量的Dirac粒子在宇宙磁场中的演化。宇宙磁场使空间度规出现各向异性。通过求解Dirac方程,得到了中微子在宇宙磁场中的表观磁矩。     

Nonlinear Force-Free Modeling of Coronal Magnetic Fields. II. Modeling a Filament Arcade and Simulated Chromospheric and Photospheric Vector Fields

We compare a variety of nonlinear force-free field (NLFFF) extrapolation algorithms, including optimization, magneto-frictional, and Grad – Rubin-like codes, applied to a solar-like reference model. The model used to test the algorithms includes realistic photospheric Lorentz forces and a complex field including a weakly twisted, right helical flux bundle. The codes were applied to both forced “photospheric” and more force-free “chromospheric” vector magnetic field boundary data derived from the model. When applied to the chromospheric boundary data, the codes are able to recover the presence of the flux bundle and the field’s free energy, though some details of the field connectivity are lost. When the codes are applied to the forced photospheric boundary data, the reference model field is not well recovered, indicating that the combination of Lorentz forces and small spatial scale structure at the photosphere severely impact the extrapolation of the field. Preprocessing of the forced photospheric boundary does improve the extrapolations considerably for the layers above the chromosphere, but the extrapolations are sensitive to the details of the numerical codes and neither the field connectivity nor the free magnetic energy in the full volume are well recovered. The magnetic virial theorem gives a rapid measure of the total magnetic energy without extrapolation though, like the NLFFF codes, it is sensitive to the Lorentz forces in the coronal volume. Both the magnetic virial theorem and the Wiegelmann extrapolation, when applied to the preprocessed photospheric boundary, give a magnetic energy which is nearly equivalent to the value derived from the chromospheric boundary, but both underestimate the free energy above the photosphere by at least a factor of two. We discuss the interpretation of the preprocessed field in this context. When applying the NLFFF codes to solar data, the problems associated with Lorentz forces present in the low solar atmosphere must be recognized: the various codes will not necessarily converge to the correct, or even the same, solution. On 07/07/2007, the NLFFF team was saddened by the news that Tom Metcalf had died as the result of an accident. We remain grateful for having had the opportunity to benefit from his unwavering dedication to the problems encountered in attempting to understand the Sun’s magnetic field; Tom had completed this paper several months before his death, leading the team through the many steps described above.     

Observational Features of Large-Scale Structures as Revealed by the Catastrophe Model of Solar Eruptions

Large-scale magnetic structures are the main carrier of major eruptions in the solar atmosphere. These structures are rooted in the photosphere and are driven by the unceas-ing motion of the photospheric material through a series of equilibrium configurations. The motion brings energy into the coronal magnetic field until the system ceases to be in equilib-rium. The catastrophe theory for solar eruptions indicates that loss of mechanical equilibrium constitutes the main trigger mechanism of major eruptions, usually shown up as solar flares, eruptive prominences, and coronal mass ejections (CMEs). Magnetic reconnection which takes place at the very beginning of the eruption as a result of plasma instabilities/turbulence inside the current sheet, converts magnetic energy into heating and kinetic energy that are responsible for solar flares, and for accelerating both plasma ejecta (flows and CMEs) and energetic particles. Various manifestations are thus related to one another, and the physics behind these relationships is catastrophe and magnetic reconnection. This work reports on re- cent progress in both theoretical research and observations on eruptive phenomena showing the above manifestations. We start by displaying the properties of large-scale structures in the corona and the related magnetic fields prior to an eruption, and show various morphological features of the disrupting magnetic fields. Then, in the framework of the catastrophe theory, we look into the physics behind those features investigated in a succession of previous works, and discuss the approaches they used.