AR6659光球色球的磁场速度场的演化特征及其与大耀斑的关系

ＡＲ６６５９是２２周以来最重要的一个活动区，它爆发了２２周最强大的高能事件。本文用云南天文台的光球、色球精细结构照片和北京天文台怀柔站的磁场速度场资料，分析了该活动区磁场速度场的二维位形和大耀斑期间的演化特征，本文分析的４个大耀斑均爆发在中性线附近的Ｎ极区磁场梯度大的地方及色球速度场的红移区，偏带观测也显示耀斑物质是向红端移动的。耀斑波沿横场传播在离本黑子群几万至十几万公里的地方激起感生耀斑，在原     

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。     

AR6659区伴随米波射电爆发的光学形态和磁场速度场特征

利用云南天文台光声谱仪１９９１年６月观测到的来自６６５９活动区的米波射电爆发记录,及其光学活动,磁场速度场的资料,作了分析研究,得到了一些有意义的结果。     

AR6659区伴随米波射电爆发的光学形态和磁场速度场特征

利用云南天文台声光频谱议１９９１年６月观测到的来自６６５９活动区的米波射电爆发记录,及其光学活动、磁场速度场的资料,作了分析研究。得到了一些有意义的结果     

太阳6659号活动区的白光耀斑

1991年6月6日我们在太阳6659号活动区观测到了一个白光耀斑.这个白光耀斑伴有强烈的H_α、X射线和射电微波发射.我们对这次自光事件作了初步的分析研究,并对它的总能量作了粗略估计.     

与耀斑相关的磁场演化

本文利用紫金山天文台太阳光谱仪缝前附属Ｄａｙｓｔａｒ滤光器拍摄的，发生在ＮＯＡＡ５３９５活动区中的三个耀斑的Ｈα单色光资料，对比北京天文台怀柔观测站取得的光球磁场资料，研究耀斑产生位置与光球磁场演化的关系，结果表明：（１）在所研究的５０个耀斑亮核中，有３８个位于新浮磁流区附近，另有少数亮核出现在磁对消区；（２）耀斑亮核多集中在横场方向交叉，剪切角大的复杂磁区，耀斑后多数区域磁场结构简化；（３）耀斑     

AR8210大活动区黑子与磁场的演化

AR8 2 1 0活动区的黑子磁场结构是反极性排列 ,开始是负极性的主黑子上半部被正极性所包围 ,随后又在主黑子下方浮现正极磁场 ,引起主黑子作顺时针方向旋转约 90°,当正极性磁场强度减弱后 ,主黑子又呈弱的逆时针方向旋转。该区域产生的高能耀斑爆发与黑子磁场变化密切联系。     

AR5312光球黑子的形态演化及运动

本文对1989年1月的AR5312活动区的形态及演化过程作了描述,着重指出:(1)活动区内存在长时期的δ磁结构,并为反转极性排列;(2)群内新磁流的浮现及快速发展的光球运动,与本活动区产生众多耀斑有密切关系。     

高能耀斑指数的功率谱及其热点分布

本文采用一个表征高能耀斑强度的综合指数,分析了太阳活动21周以来(1976.7—1991.2)级别≥M1.0的X射线耀斑和能量≥10Mev的质子耀斑综合指数的时空分布,提出在研究时段内太阳上的13个高能耀斑“热点”。这些热点活动区反复回转,爆发了占总指数58.1％的高能耀斑。本文还讨论了高能耀斑热点的特征及其与大尺度磁场演化的关系。结果表明,高能耀斑热点与大尺度磁场的演化关系密切,前者受后者的调制。     

确定太阳横向磁场方位角的综合方法

本文分析了现有几种常用的确定太阳磁场横向分量方位角的方法，如势场法，Ｋｒａｌｌ法、吴－艾法和＂方位角连续＂法，作者认为这些方法各有不同的适用范围，其中任何一种方法都不能单独确定太阳横向磁场。在此分析的基础上，提出了确定太阳横向磁场方位角的综合方法。该法的要点是：用势场法和Ｋｒａｌｌ法分别处理同一磁场观测资料，比较这两种方法所得到的横场分布图，找出它们的相同区域和有差别区域。从相同区域出发，利用＂无力因子相近＂假定，可以推断有差异区域的横场方位角。本文提供的应用实例初步显示了综合方法的有效性。     

Relationship between Powerful Flares and Dynamic Evolution of the Magnetic Field at the Solar Surface

Powerful flares are closely related to the evolution of the complex magnetic field configuration at the solar surface. The strength of the magnetic field and speed of its evolution are two vital parameters in the study of the change of magnetic field in the solar atmosphere. We propose a dynamic and quantitative depiction of the changes in complexity of the active region: E=u×B, where u is the velocity of the footpoint motion of the magnetic field lines and B is the magnetic field. E represents the dynamic evolution of the velocity field and the magnetic field, shows the sweeping motions of magnetic footpoints, exhibits the buildup process of current, and relates to the changes in nonpotentiality of the active region in the photosphere. It is actually the induced electric field in the photosphere. It can be deduced observationally from velocities computed by the local correlation tracking (LCT) technique and vector magnetic fields derived from vector magnetograms. The relationship between E and ten X-class flares of four active regions (NOAA 10720, 10486, 9077, and 8100) has been studied. It is found that (1) the initial brightenings of flare kernels are roughly located near the inversion lines where the intensities of E are very high, (2) the daily averages of the mean densities of E and its normal component (E _n) decrease after flares for most cases we studied, whereas those of the tangential component of E (E _t) show no obvious regularities before and after flares, and (3) the daily averages of the mean densities of E _t are always higher than those of E _n, which cannot be naturally deduced by the daily averages of the mean densities of B _n and B _t.     

强质子耀斑活动区的形态和旋转特征

本文研究结果表明：同一黑子群在日面期间的顺或反时针方向的旋转运动会先后并存．质子耀斑前1～2无，黑子群的旋转角速度达到极大．耀斑后，磁绳的松弛，黑子群可能会反向旋转，强的剪切过程和质子耀斑可能会再度出现．强质子耀斑活动区的共同特征是：（1）形态为单个团状结构δ型黑子，即众多异极性本影核紧锁在同一黑子半影中；（2）黑子面积＞1000×10－6半球面积，日面跨度＞10°；（3）黑子群都有快速的旋转运动．这类活动区，如果在日面西部活动性明显地增强，那么这个活动区在未来转到日面边缘及其背后、或再次从日面东边缘转出时，定能再次爆发耀斑和伴随较强质子事件。     

Multiresolution Analysis of Active Region Magnetic Structure and its Correlation with the Mount Wilson Classification and Flaring Activity

Two different multiresolution analyses are used to decompose the structure of active-region magnetic flux into concentrations of different size scales. Lines separating these opposite polarity regions of flux at each size scale are found. These lines are used as a mask on a map of the magnetic field gradient to sample the local gradient between opposite polarity regions of given scale sizes. It is shown that the maximum, average, and standard deviation of the magnetic flux gradient for α,β,β γ, and β γ δ active-regions increase in the order listed, and that the order is maintained over all length scales. Since magnetic flux gradient is strongly linked to active-region activity, such as flares, this study demonstrates that, on average, the Mt. Wilson classification encodes the notion of activity over all length scales in the active-region, and not just those length scales at which the strongest flux gradients are found. Further, it is also shown that the average gradients in the field, and the average length-scale at which they occur, also increase in the same order. Finally, there are significant differences in the gradient distribution, between flaring and non-flaring active regions, which are maintained over all length scales. It is also shown that the average gradient content of active-regions that have large flares (GOES class “M” and above) is larger than that for active regions containing flares of all flare sizes; this difference is also maintained at all length scales. All of the reported results are independent of the multiresolution transform used. The implications for the Mt. Wilson classification of active-regions in relation to the multiresolution gradient content and flaring activity are discussed.     

太阳AR7646、7647活动区黑子磁场和新的射电微耀斑爆发

１９９４年１月５日日面上产生的１次１Ｎ／Ｍ１．０耀斑爆发，射电１．４２ＧＨｚ高时间分辨率观测也同时接收到，在小爆发过程里伴有５３个脉冲信号叠加在连续辐射背景上，是很罕见的现象。在ＡＲ７６４６的黑子前导区域，５日有２处新浮的小黑子对，磁场分别成细小磁流管平行和交又状态，是产生爆发的根源；脉冲信号是微耀斑在射电方面的瞬时辐射现象，由耀斑连续产生微能量释放而出现，单个的能量释放为（０．３—３．３）×１０１０焦耳。在能量释放过程里，非热电子加速起到重要作用。     

A Statistical Study on the Reconnection in Boundary Layers of Small-scale Magnetic Flux Tubes in Solar Winds

With the data from WIND satellite in 1995—2005, the small-scale magnetic ?ux tubes determined with two methods, i.e., the arti?cial recognition and program selection respectively, are compared. It is found that there are magnetic reconnections in the boundary layers of 41% small-scale magnetic ?ux tubes determined with the program selection method, which is similar to the re- sult of small-scale magnetic ?ux tubes determined with the method of arti?cial recognition. The features of magnetic reconnections, such as the magnetic shear angle, magnetic ?eld strength, and duration of the dissipation region of recon- nection at the small-scale ?ux tubes’ boundaries determined from both methods have the same statistical tendency. This shows that there is no essential differ- ence in the properties of reconnections in the boundary layers of the small-scale magnetic ?ux tubes determined with the two methods. Hence the data yielded by both methods can be used as the samples for statistically studying the events of reconnection in the front and back boundary layers of small-scale ?ux ropes. There are totally 71 magnetic reconnection events selected in this paper. Our statistical result shows that in 50 events (70%) the decrease of magnetic ?eld strength in the dissipation region of reconnection is larger than 20%, and in 47 events (66%) the magnetic shear angle is larger than 90 degrees. These indicate that the magnetic reconnections in boundaries of the small-scale magnetic ?ux tubes are more likely to be anti-parallel. The statistics has been performed sep- arately in the reconnections of the front and back boundary layers of small-scale magnetic ?ux tubes. The results show that the features of reconnections in the front and back boundaries are similar to each other, which is different from the various properties in the front and back boundaries of the magnetic clouds, and this means that the expansion in the large-scale magnetic ?ux tubes, such as magnetic clouds, does not happen in the small-scale magnetic ?ux tubes.     

On the propagation of hydromagnetic waves in a plasma of thermal and suprathermal components

The propagation of MHD waves is studied when two ideal fluids, thermal and suprathermal gases, coupled by magnetic field are moving with the steady flow velocity. The fluids move independently in a direction perpendicular to the magnetic field but gets coupled along the field. Due to the presence of flow in suprathermal and thermal fluids there appears forward and backward waves. All the forward and backward modes propagate in such a way that their rate of change of phase speed with the thermal Mach number is same. It is also found that besides the usual hydromagnetic modes there appears a suprathermal mode which propagates with faster speed. Surface waves are also examined on an interface formed with composite plasma (suprathermal and thermal gases) on one side and the other is a non-magnetized plasma. In this case, the modes obtained are two or three depending on whether the sound velocity in thermal gas is equal to or greater than the sound velocity in suprathermal gas. The results lead to the conclusion that the interaction of thermal and suprathermal components may lead to the occurrence of an additional mode called suprathermal mode whose phase velocity is higher than all the other modes.