共查询到20条相似文献，搜索用时 203 毫秒
1.
观测研究表明有利于磁重联的新浮磁流与日冕物质抛射(CME)有密切关系．利用数值模拟的方法,新浮磁流触发CME的物理模型对观测结果进行了物理解释．基于这种模型,不考虑重力和热传导, 2．5维的数值模拟的理论结果显示:是否能够触发暗条爆发及CME,取决于新浮磁流磁通量的大小、浮现的位置以及其磁极走向,并给出了能够触发暗条爆发与不能触发爆发的参数空间．利用2002年和2003年的15个暗条爆发事例以及2002年的44个非爆发事例,对新浮磁流磁通量的大小、浮现的位置以及磁极走向进行了统计研究．结果表明并非所有的新浮磁流都能够使暗条失去平衡,形成CME．统计结果基本上支持了数值模拟的理论结果．这个结果可为空间天气预报研究提供有用的参考信息． 相似文献
2.
本文用数据方法分析了紫金山天文台色球望远镜观测的１９９６年３月２４日３Ｂ级双带主资料，结果表明：由于新浮磁流改变背景磁场，光球剪切运动引起暗条圆柱轴向磁力线扭转而使暗条电流增加，致使暗条整体力学平衡破坏，驱动暗条向上运动。并对暗条上升运动与耀斑爆发的物理关系进行了分析讨论。 相似文献
3.
利用色球Ha单色像、TRACE和SOHO／EITEUV单色像、SOH0／LASCO白光日冕观测及SOH0／MDI光球磁图，对2003年8月25日日面AR0442边界上2个暗条爆发的不同动力学行为及与之相关的耀斑、耀斑后环和CME等现象进行了分析。主要结论如下：(1)2个暗条的激活态和爆发过程有明显不同：暗条F1先变粗变黑，出现明显分叉，然后表现为whiplike爆发；而暗条F2一部分先消失，其余部分出现水平的轴向运动，最后F2整体爆发。(2)2个暗条的爆发机制是不同的：F1的爆发可能与新浮磁流密切相关，而F2的爆发与F1爆发产生的双带耀斑的分离运动和相互作用密切相关。 相似文献
4.
本文利用光球磁场、色球Hα单色像和Hβ速度场等观测资料，分析了1993年5月日面AR7500中3个暗条的演化和动力学行为，得出4个结论(1)3个暗条中两个是右旋暗条，一个是左旋暗条。(2)暗条附近两侧的色球纤维和光球横场几乎平行于暗条长轴，暗条端点处的黑子没有呈现明显的涡旋结构。(3)尖角处因为轴向场取向不同，一直没有发生暗条合并，即使其中一个右旋暗条消失后又重新形成也如此。(4)几天持续存在的左旋暗条，在两天的观测中未出现扰动激活，其中部为杂乱而不明显的运动图案。本文还讨论了可以用暗条的扭曲磁流绳模型来解释暗条的这些动力学行为，以及一些尚待进一步澄清的问题。 相似文献
5.
6.
本文分析了廿一周峰年期间云南天文台观测到的廿个无黑子区耀斑,得到如下结果: 1.无黑子区耀斑的一般特征是:1) 无黑子区耀斑的自然产率约3％,2) 其卡林顿经度分布有向东飘移的趋势,3) 无黑子区的耀斑多为低能耀斑,4) 无黑子区耀斑产生的背景条件和黑子区耀斑一样,必须在耀斑区的太阳大气中存在异极性磁场结构。无黑子区耀斑都发生在沿大尺度磁场中性线(H_=0)延伸的暗条两侧或其附近。 2.在耀斑前,由于磁场的扰动,使被浮托在H_=0线上的宁静暗条在耀斑前几小时到一两天激活,临近耀斑位置的一段暗条先是发展增大,同时伴随着谱斑增亮,在耀斑爆发前几分钟或与耀斑发展的同时,该暗条迅速衰减乃至完全消失。与此同时,有的无黑子活动区的可见纤维与暗条的交角由大变小,表明活动区所受的力由挤压力逐渐转化为剪切力。本文还粗略地估计了无黑子区耀斑的能量。 相似文献
7.
利用云南天文台色球Hα单色像、SOHO/EITEUV单色像、SOHO/LASCO白光日冕观测、SOHO/MDI光球磁图及Nobeyama17GHz微波射电观测资料对2004年4月11日AR0588中的环形暗条爆发进行了初步的分析。主要结论如下:(1)爆发的暗条呈现封闭的环形。在Hα观测上爆发前有明显的激活态,表现为西半环变粗变厚,断裂出现缺口并缓慢向西南方向上升。在EIT195 观测上,此暗条爆发表现出两条扎根于爆发源区的亮带,其顶部可能是爆发中的暗条,而这两条亮带是暗条的两条腿。该暗条爆发是动力学爆发,但暗条等离子体在爆发过程中也受到明显的加热。(2)该暗条爆发伴随有一个明显的双带耀斑。一个带位于暗条爆发的中心,几乎不动,而另一个带呈环状包围爆发的暗条,展示明显的分离运动。这两个带之间,在耀斑后期出现明显的耀斑后环。(3)这一暗条爆发及耀斑与LASCO观测到的一个快速的、具有典型三部分结构的partialHaloCME在时间和空间上是密切相关的。 相似文献
8.
利用多波段联合观测数据,综合分析研究了一个发生于2007年5月23日的日冕物质抛射(Coronal Mass Ejection,CME)爆发事件的起源和初始阶段的物理演化过程.该CME起源于活动区10956内的一个并没有严格地位于活动区极性反转线上的U形活动区暗条,该暗条首先被扰动,然后从中间部分开始缓慢上升.在暗条上升运动过程中,从极紫外和软X射线像上可观测到位于暗条上方的日冕磁环也在不断地上升并且有持续向外的扩张运动.最终,这些冕环和暗条一起爆发并伴随着一个位于暗条断开位置附近的日冕暗化区域的形成.这一爆发过程还伴随着一个静止轨道业务卫星(GeostationaryOperational Environmental Satellites,GOES)软X射线流量级别为B5.3的亚耀斑发生,该光斑显示出与CME之间具有在时间和空间上的紧密联系.与CME的"标准"磁流绳模型一致,这些太阳表面活动可以看作是CME的初始演化阶段在日面上的表现信号,并且该CME的亮前锋可能是由预先存在于暗条上方的冕环体系直接演化而来.另外,文中还讨论了与该事件相关的暗条爆发、耀斑、冕环扩张和消失以及日冕暗化之间的关系. 相似文献
9.
本文利用光球磁场、色球Hα单色像和Hβ速度场等观测资料，分析了1993年5月日面AR7500中3个暗条的演化和动力学行为，得出4个结论：（1）3个暗条中两人是右旋暗条，一个是左旋暗条。（2）暗条附近两侧的色球纤维和光球横场几乎平行于暗条长轴，暗条端点处的黑子没有呈现明显的涡旋结构。（3）尖角处因为轴向场取向不同，一直没有发生暗条合并，即使其中一个右旋暗条消失后又重新形成也如此。（4）几天持续存在的左旋暗条，在两天的观测中未出现扰动激活，其中部为杂乱而不明显的运动因素。本文还讨论了可以用暗条的扭曲磁流绳模型来解释暗条的这些动力学行为，以及一些尚待进一步澄清的问题。 相似文献
10.
我们利用紫台1981年5月16日获得的发生在MW.No.22278复合群(N12°、E14°)的一个双带质子大耀斑的高分辨黑子白光和H_α色球资料,讨论了这个大耀斑发生前8小时和大耀斑初相时光球和色球的变化,分析了浮现磁流、冲浪、暗条爆发与耀斑开始的关系,发现中性线旁异极性磁流的生长产生的冲浪造成了中性线处暗条的扰动和爆发,并导致了大耀斑。从而验证并扩充了浮现磁流的耀斑模型。 相似文献
11.
David L. Glackin 《Solar physics》1975,43(2):317-326
All active regions are born as Emerging Flux Regions (EFRs) which appear in H as two small plages of opposite polarity connected by parallel dark arches. After a brief review of the properties of EFRs, we report on new observations of the birth of an EFR and apparent subsequent field reconnection. We review fluxrope theories, predict the appearance of EFRs, then modify this picture on the basis of high resolution observations. We arrive at a model of this phenomenon that encompasses relevant aspects such as the axial tilt of spot groups, the observed rotation of EFRs as they emerge, and the fact that EFR fluxtubes are made up of many discrete strands.We investigate the relation of the positions of emergence of EFRs to the chromospheric network. We find that new EFRs can be much smaller than supergranules. 相似文献
12.
G.A. Chapman 《Solar physics》1998,183(1):15-28
We have observed several emerging flux regions (EFRs) using the Video Spectra-Spectro-Heliograph (VSSHG) at the San Fernando Observatory (SFO). The best studied region, NOAA 7968, was near disk center when it was observed on 5–8 June 1996. This EFR showed no organized upflow between the leader and follower spots over the 4-day period covered by our observations. The main concentrations of magnetic flux in the region (leader and follower) showed a slow separation as flux emerged, but little or no upflow was seen. Two other EFRs were observed for part of a single day each and one region was observed for only one sequence. For all regions observed, no discrete features were seen between the leader and follower polarity sunpots that had upflowing material as the regions grew. In all cases, the downward velocities were smaller in area than the magnetic parts of the regions. At times there were several localized areas of greater-amplitude downflows near sunspots. 相似文献
13.
The active region NOAA 6555 had several locations of highly sheared magnetic field structure, yet, only one of them was the site for all the five X-class flares during its disk passage in March 1991. The pre-flare observations of high-resolution H filtergrams, vector magnetograms and H Dopplergrams of the 2B/X5.3 flare on 25 March 1991 show that the flaring site was characterized by a new rising emerging flux region (EFR) near the highly sheared magnetic field configuration. The polarity axis of the emerging flux was nearly perpendicular to the pre-existing magnetic neutral line. The location of the EFR was the site of initial brightening in H. The post-flare magnetograms show higher magnetic shear at the flare location compared to the post-flare magnetograms, which might indicate that the EFR was sheared at the time of its emergence. As the new EFR coincided with the occurrence of the flare, we suggest that it might have triggered the observed flare. Observations from Big Bear Solar Observatory and Marshall Space Flight Center also show that there was emergence of new flux at the same location prior to two other X-class flares. We find that out of five observed X-class flares in NOAA 6555, at least in three cases there are clear signatures of flare-related flux emergence. Therefore, it is concluded that EFRs might play an important role in destabilizing the observed sheared magnetic structures leading to large X-class flares of NOAA 6555. 相似文献
14.
We describe the morphological evolution of photospheric features in an emerging flux region (EFR), on the basis of high-resolution photographs taken with the Vacuum Tower Telescope at Sacramento Peak Observatory. Individual alignments of darkened intergranular lanes have a lifetime of only about 10 min; they may represent the tops of emerging flux loops. Roundish darkened patches within the intergranular lanes (protopores) may precede the birth of a pore, or may disappear again within a few hours. The birth of one pore coincides with the area of a conspicuous downflow observed in the spectrograms. The majority of the pores in the EFR grow in area and darken; their growth times vary between 1 and 6 hr. Various modes of growth are observed. Some pores dissolve again within a few hours after their birth.The long axis of the whole EFR rotates by 2 deg hr-1 towards alignment parallel to the equator, with leading polarity closest to the equator. The ring of pores surrounding the EFR expands with velocities of about 0.7 km s-1 in the east-west direction. There is strong velocity shear: the leading edge of the leading pore moves perpendicular to the general expansion of the ring of pores.Filigree is absent near the fast growing pores of following polarity and near the alignments.Based on observations obtained at the Sacramento Peak Observatory (operated by the Association of Universities for Research in Astronomy, Inc. under contract with the National Science Foundation). 相似文献
15.
We have compared the rates at which flux emerges in active and quiet solar regions within the sunspot belts. The emerging flux regions (EFRs) were identified by the appearance of arch filament structures in H. All EFRs in high-resolution films of active regions made at Big Bear in 1978 were counted. The comparable rate of flux emergence in quiet regions was obtained from SGD data and independently from EFRs detected outside the active region perimeter on the same films. The rate of flux emergence is 10 times higher in active regions than in quiet regions. A sample of all active regions in 31 days of 1983 gave a ratio of 7.5. We discuss possible mechanisms which might funnel new magnetic flux to regions of strong magnetic field. 相似文献
16.
Joan A. Vorpahl 《Solar physics》1973,28(1):115-122
I examined a moderately active sunspot group, McMath 9735, and found that 15 of 16 flares observed in 1968, October 20–21 occurred near, and were preceded by, at least one of several EFR's (Emerging Flux Regions) in the area. Flares were larger and more numerous when: (1) the EFR appeared close to already existing spots, (2) a large amount of filament reorientation was occurring, and when (3) the EFR was most active, i.e., it was increasing in area and brightness and was accompanied by violent surging and great brightness fluctuations at the feet of the dark fibrils. Only two flares occurred at an inverted EFR, i.e., a leading spot with f polarity, however the largest event (2B) of the 15 quickly spread to this region after starting in a different EFR. A sunspot appeared in the inverted emerging flux region less than three hours after the flares. However this is thought to be merely an indication of the growing EFR and, therefore, a secondary effect. 相似文献
17.
G.A. Chapman 《Solar physics》2002,209(1):141-152
This paper is a study of NOAA region 9144, an emerging flux region (EFR) which grew rapidly beginning 25 August 2000. This
region was visible in SOHO data at 0 UT on 25 August 2000 as a small, isolated spot. It was recognizable as an active region
with multiple spots by 06:00 UT on the 25th and was a fully developed AR by 24h UT on the 26th of August. Data are presented from the Michelson Doppler Imager (MDI) experiment on the Solar and Heliospheric
Observatory satellite (SOHO), from Big Bear Solar Observatory (BBSO) and from the San Fernando Observatory (SFO). The MDI
data are Dopplergrams, magnetograms, and continuum images. The BBSO data are high-resolution Hα filtergrams. The SFO data
are Dopplergrams, magnetograms and continuum images from the Video SpectraSpectroHeliograph (VSSHG). MDI Doppler images show
that during the rapid growth of this EFR during the day of 26 August, the most obvious feature in area and lifetime is a red-shifted
area in the trailing part of the region. SFO Doppler images show a more complex pattern, but still dominated by red shifts
in the trailing part of the region near the end of the day of 26 August. 相似文献
18.
J. J. Brants 《Solar physics》1985,98(2):197-217
Scatter plots of various pairs of spectral-line parameters that describe the magnetic field and the line-of-sight velocity are discussed in order to relate magnetic structures and the line-of-sight velocity field with characteristic areas of an emerging flux region (EFR).Strong magnetic fields, occurring over about 20% of the resolution elements in the EFR, are either slightly to moderately inclined or transverse. Slightly to moderately inclined strong fields occur in patches near the border of the EFR; the filling factors per resolution element are large, and field strengths are between 800 and 2000 G, and up to 2500 G in pores. There are only a few faculae in the EFR; most of these are located near rapidly growing pores of following polarity.The strongly inclined strong magnetic fields, with field strengths exceeding 1000 G, are located in slightly darkened resolution elements near the line B
= 0 separating the magnetic polarities, near large-scale and small-scale upflows. In the central region of the EFR there are some small elements with strongly inclined field of low average field strength of about 500 G, and a tendency for a small-scale upward velocity. These elements may correspond to tops of flux loops during emergence.In 80% of the resolution elements within the EFR the magnetic flux density (averaged over the resolution element) is low, less than 120 G.There is a persistent large-scale velocity field, with upflows near the line B
= 0 separating the magnetic polarities and with downflows near rapidly growing pores of following polarity. Some examples of strong small-scale upflows are found in the central region of the EFR, and strong small-scale downflows near rapidly growing following pores. Within the pores and faculae there are no significant small-scale line-of-sight velocities.Based on observations obtained at the Sacramento Peak Observatory (operated by the Association of Universities for Research in Astronomy, Inc. under contract with the National Science Foundation). 相似文献
19.
本文分析了ＮＯＡＡ６３６１活动区中的一些现象，发现该活动区在衰亡阶段经历了两次同极性黑子的复合过程，复合后的黑子本影间均有光桥存在，观测结果倾向于支持Ｐａｒｋｅｒ１９７９年提出的黑子多磁流管模型。１４日复合后的黑子本影还顺时针方向旋转了约７０度角，从半影纤维的同样顺时针旋转可以认为：该黑子的半影磁场并非是普遍认为的简单的本影磁场的发散部分。我们还观测到另外两个比较有趣的现象：①δ黑子中的ｐ极性黑子 相似文献
20.
As one of the most violent activities in the solar atmosphere,white-light flares(WLFs)are generally known for their enhanced white-light(or continuum)emission,which primarily originates in the solar lower atmosphere.However,we know little about how white-light emission is produced.In this study,we aim to investigate the response of the continua at 3600?and 4250?and also the Hαand Lyαlines during WLFs modeled using radiative hydrodynamic simulations.We take non-thermal electron beams as the energy source for the WLFs in two different initial atmospheres and vary their parameters.Our results show that the model with non-thermal electron beam heating clearly shows enhancements in the continua at 3600?and 4250?as well as in the Hαand Lyαlines.A larger electron beam flux,a smaller spectral index,or an initial penumbral atmosphere leads to a stronger emission increase at 3600?,4250?and in the Hαline.The Lyαline,however,is more obviously enhanced in a quiet-Sun initial atmosphere with a larger electron beam spectral index.It is also notable that the continua at 3600?and 4250?and the Hαline exhibit a dimming at the start of heating and reach their peak emissions after the peak time of the heating function,while the Lyαline does not show such behaviors.These results can serve as a reference for the analysis of future WLF observations. 相似文献