两个太阳活动区中纵向磁场的分形特征(英文)

本文研究了1990年3月25日活动区AR5988和1990年8月30日活动区AR6233中太阳磁场的分形特征．主要结果如下：（1）两个活动区中的纵向磁场分布不满足分形布朗曲面；（2）两个活动区中磁场的分形特征十分不同；（3）描述这两个活动区磁场分形特征的四个统计参置随时间演化，本文扼要讨论了这些结果的物理意义。     

AR5572中一个宁静暗条的缠绕运动与磁场的关系

1989年7月8日,在AR5572中,北京天文台怀柔太阳观测站观测到宁静日珥的缠绕运动。磁场观测表明,它与磁对消密切相关。     

太阳大气中矢量磁场信息的推导

一种能从观测到的斯托克斯轮廓中提取太阳表面矢量磁场信息的方法在本文中提出，它利用斯托克斯轮廓非线心的极值点处相应参量对波长的导数为零这一数学事实，假设表面附近磁场矢量及热力学参量的变化梯度足够小以致所考虑的极值点的波长位置不随深度改变或此变化呆忽则使得偏振辐射围方程组得到极大的简化；再应用数值方法从此简化方程组中解出辐射表面附近的磁场矢量参数。通过拟合理论轮廓表明该法确实可以得到表面近似的磁场矢量     

准开放磁场线区域模型

为了解释日冕中高能电子束和太阳耀斑中的快速过程,本文提出在活动区双极黑子上空存在一个准开放磁场线区域的定性模型。如图1所示,准开放磁场线区域被确定在开放磁场线下面和耀斑环顶部之间。 由于那里的快速磁重联或撕裂、爆炸式的能量释放引起了区域性的等离子体加速。那些被加速到10—100keV的高能电子束沿着开放的磁场线从太阳大气等离子体逃逸到行星际等离子体中。在每个连续的高度上将产生朗缪尔波等离子体辐射。朗缪尔波同低     

太阳网络内磁场的研究

本论文可分为两个部分,第一部分系统地综述了太阳大气中的小尺度活动现象,并给出了详细的统计结果。小尺度磁场的对消激发小尺度活动现象。这些磁场显著影响太阳大气的结构和动力学特征,这产场影响能量从小阳大气的结构和动力学特征,如这些磁场影响能量从太阳大气的低层向高层传输,针状体动力学（小尺度磁活动）能够把物质从光球输送到日冕,及小尺度磁场对消产生的Ｘ射线亮点等等。近几年,大多数太阳物理学家认为小尺度磁场对     

与耀斑双带重合的一对共轭电流带

利用SDO (Solar Dynamics Observatory)/HMI (Helioseismic and Magnetic Imager)观测到的矢量磁图,研究了与活动区AR12673上爆发的一个X9.3级耀斑(2017年9月6日)的相关电流分布和演化.结果显示,在该活动区的磁中性线两边存在一对方向相反的电流密度约为0.4 A/m~2的长电流带,可称其为一对共轭电流带.这对共轭电流带在耀斑发生之前、期间以及之后一直存在;并且观测到,该耀斑的两个亮带的位置几乎刚好与两个电流带重叠,它们的形状也极其相似. 9月6日电流总强度演化曲线表明,电流强度在X9.3级强耀斑爆发期间出现快速增加的现象,这种现象持续了几个小时.这一研究结果有力支持了磁准分界面(Quasi-Separatrix Layer, QSL) 3维重联模型.     

谱线形成深度理论及其应用（Ⅲ）：太阳矢量磁场结构的推导

叙述了谱线形态深度理论在推导太阳矢量磁场空间结构上的应用，列举了有典型意义的工作，指出了用响应函数比有贡献函数导出的结果更好的原因以有产的局限性，作为对比，也举例了说明了不依赖于这种理论来推导矢量磁场结构的方法。     

关于磁剪切发展的一个探讨

在以无力磁场的非势特征近似描述磁剪切位形时,无力因子α即可做为磁剪切的量度;而磁剪切的发展则为方程所解析描述.这里G=B/t×B,可称为磁剪切产生函数.该方程表明,磁剪切产生于局地的发电机作用,是磁场与磁流体运动相互作用的结果.相反极性磁结构的挤压,磁通量的浮现与下沉,都可以和剪切运动一样,有效地导致磁剪切的发展.     

太阳活动区同极磁流合并与高能耀斑

本文对六个活动区的同极磁流合并现象进行了分析,同极磁流合并可以分为两类。一类是在同极磁流合并之前,其间的异极性磁流很弱,它们的合并不是由于互相靠近而是由于相对延伸,另一类是在合并之前,其间有较强的异极性磁流,合并后有的明显靠近,有的则看不到靠近现象。高能耀斑与同极磁流合并有密切关系。6个活动区中发生的同极磁流合并几乎都与高能耀斑有关,这个结果可用于M和X级X射线耀斑的预报。文中还给出了用于预报的同极磁流合并的定义。     

1988年9—10月各活动区的同极磁流合并与强X射线耀斑

木文对1988年9—10月份各活动区的纵场磁图作了同极磁流合并过程的统计分析,并且证认了与之有关的强X射线耀斑(M、X级耀斑)。结果表明,同极磁流合并是少数(4％)活动区磁场位形出现的演化过程,它的强X射线耀斑的产率很高。     

磁通量喷发的大气响应Ⅰ.日冕物质喷射机制

本文对盔状冕流底部磁通量喷发的大气响应进行数值模拟。数值结果表明:在喷发磁场的作用下,原冕流中的物质将受到压缩并向上运动,形成高密度亮环结构,同时在环的前方出现快磁声波,在环的下方出现低密度暗区。据此我们认为,磁通量喷发可能是触发环形日冕物质喷射的一种重要机制。     

Magnetic Field Vector Retrieval With the Helioseismic and Magnetic Imager

We investigate the accuracy to which we can retrieve the solar photospheric magnetic field vector using the Helioseismic and Magnetic Imager (HMI) that will fly onboard of the Solar Dynamics Observatory by inverting simulated HMI profiles. The simulated profiles realistically take into account the effects of the photon noise, limited spectral resolution, instrumental polarization modulation, solar p modes, and temporal averaging. The accuracy of the determination of the magnetic field vector is studied by considering the different operational modes of the instrument.     

Vector Magnetic Field Measurement of NOAA AR 10197

A set of two-dimensional Stokes spectral data of NOAA AR 10197 obtained by the Solar Stokes Spectral Telescope (S3T) at the Yunnan Observatory are qualitatively analyzed. The three components of the vector magnetic field, the strength H, inclinationγand azimuth X, are derived. Based on the three components, we contour the distributions of the longitudinal magnetic field and transverse magnetic field. The active region (AR) has two different magnetic polarities apparent in the longitudinal magnetic map due to projection effect. There is a basic agreement on the longitudinal magnetic fields between the S3T and SOHO/MDI magnetograms, with a correlation coefficientρBl = 0.911. The transverse magnetic field of the AR has a radial distribution from a center located in the southwest of the AR. It is also found that the transverse magnetic fields obtained by Huairou Solar Observing Station (HRSOS) have a similar radial distribution. The distributions of transverse magnetic field obtained by S3T and HRSOS have correlation coefficients,ρAzimu = 0.86 andρBt = 0.883, in regard to the azimuthal angle and intensity.     

Correlation between Solar Flare Productivity and Photospheric Magnetic Field Properties II. Magnetic Gradient and Magnetic Shear

With 1353 vector magnetograms observed at Huairou Solar Observing Station (HSOS), a statistical analysis is made on the relationship among solar flares, magnetic gradient, and magnetic shear. The results suggest that flare productivity has positive correlations with the gradient and the shear, which can be well fitted by the Boltzmann sigmoidal function. In the vicinity of neutral lines, high gradient and strong shear are roughly coincident in time but barely in position. In addition, flare productivity is more sensitive to the length of neutral lines with strong gradient and shear (L _gs) than independently with strong gradient (L _g) or strong shear (L _s), which means that L _gs can be a better parameter for solar flare forecasting models. Finally, an algorithm to evaluate projection effects on the statistical results is proposed.     

速度切变对撕裂模不稳定性影响的初步分析

在电流片两侧的基态速度场与磁场相互平行的位形下,讨论了速度切变对撕裂模不稳定性的影响.结果表明,只有当速度场的相对变化率与磁场的相对变化率符号相同(Sign(v_0/v_0)=sign(B_0~')),|v_0~'/v_0|≥|B_0'/B_0|时,速度切变有利于不稳定增长,否则不利于不稳定增长.     

Preprocessing of Vector Magnetograph Data for a Nonlinear Force-Free Magnetic Field Reconstruction

Knowledge regarding the coronal magnetic field is important for the understanding of many phenomena, like flares and coronal mass ejections. Because of the low plasma beta in the solar corona, the coronal magnetic field is often assumed to be force-free and we use photospheric vector magnetograph data to extrapolate the magnetic field into the corona with the help of a nonlinear force-free optimization code. Unfortunately, the measurements of the photospheric magnetic field contain inconsistencies and noise. In particular, the transversal components (say B _x and B _y) of current vector magnetographs have their uncertainties. Furthermore, the magnetic field in the photosphere is not necessarily force free and often not consistent with the assumption of a force-free field above the magnetogram. We develop a preprocessing procedure to drive the observed non–force-free data towards suitable boundary conditions for a force-free extrapolation. As a result, we get a data set which is as close as possible to the measured data and consistent with the force-free assumption.