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1.
利用１９９８年１０月３日北京天台怀柔太阳观测站的高质量磁图,对给定的太阳宁静区两种不同极性的磁场进行为分析。结果表明,空间功率谱在超米粒和中米粒尺度具有明显的尖峰结构,这对应于空间周期性分布的网络和内网络磁结构。结果也显示出,超米粒边缘所包含的两种极性场中,其中的一种极性占优势。通过瞬态功率谱的分析,得出网络和内网络场寿命之间的比例关系,这一结果和其他学得出的超米粒和中米粒对流寿命之间的关系相 相似文献
2.
以1988年9月5日北京天文台怀柔太阳观测站高分辨率和高灵敏度磁强图为基础,首次给出了对一太阳宁静区小尺度磁场空间分布的二维功率谱。 尽管从总体上,功率谱的分布呈现从低频分量向高频分量迅速衰减的趋势,但是,反映小尺度磁场分布的不同尺度空间周期性的分离的尖峰,是功率谱的最主要特征。 本文的主要结果可概括为下列两点: (1)太阳宁静区的磁通量不仅凝聚在分离的、具有相对较强磁通量密度的磁结构内,而且磁结构的空间分布也呈现分离的尺度不同的周期。 (2)小尺度磁场空间分布的最显著的周期,具有超米粒的空间尺度。这与以往磁对流理论与有关观测结果相一致。在功率谱中,还可以证认相应于亚超米粒,及亚超米粒和超米粒之间尺度的空间周期的大量尖峰。这是本文首次得到的。 包含更多观测资料的进一步工作是必须的,特别是获得对同一宁静区的速度场和磁场同时性的二维功率谱,对研究磁场和对流速度场的相互作用是有重要意义的。观测的功率谱与理论预测谱的比较,将有助于理解太阳光球分离磁结构形成的物理过程。 相似文献
3.
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。 相似文献
4.
利用怀柔太阳观测站的300余对光球(FeIλ5324.19A)和色球(H_βλ4861.34A)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,发现色球磁场反转结构可能有4种不同的存在形式. 相似文献
5.
太阳磁场的极性反转线(Polarity Inversion Line, PIL)是研究太阳活动、分析太阳磁场结构演变和预测太阳耀斑最重要的日面特征之一.磁场极性反转的位置是太阳耀斑和暗条可能出现的位置."先进天基太阳天文台(ASO-S)"是中国首颗空间太阳专用观测卫星,其搭载的"全日面矢量磁像仪(Full-Disk Vector Magnetograph, FMG)"主要任务是探测高空间、高时间分辨率的全日面矢量磁场.为了提高观测数据使用效率、快速监测太阳活动水平、提高太阳耀斑与日冕物质抛射的预报水平以及更好地服务于FMG数据处理与分析系统,采用了图像自动识别与处理技术,更加精确有效地检测极性反转线.从支持向量机(Support Vector Machine, SVM)的模型出发,将极性反转线位置的探测问题转化为一个模式识别中的二分类问题,提出了一种基于支持向量机的极性反转线检测算法,自动探测与识别太阳动力学天文台(Solar Dynamics Observatory, SDO)日震和磁成像仪(Helioseismic and Magnetic Imager, HMI)磁图的极性反转线位置.与现有算法的对比结果表明,此算法可以精确直观地检测太阳活动区的极性反转线. 相似文献
6.
本文介绍一组短分米波（1．42GHz）太阳微耀斑的射电和光学辐射特征，它们包含53个叠加在连续辐射背景上的射电快速精细结构（FFS），即准周期快速脉冲链（称微耀斑），它们的形态相似，强度大约在150－200sfu范围内，其寿命（半功率宽）大多为15－50ms，有18个分离的双峰结构，该事件产生的7646活动区中出现两处新浮现的几个小黑子，呈现复杂极性，可能存在多重交叉小磁流环多次重联的复杂状况．本文定性地讨论了其产生机制，支持电流环爆炸性聚合模型的理论。 相似文献
7.
本文提出分段零平均方法,引用点间加零方法,利用周期图以及自相关功率谱,对八十年代美国SMM卫星所采集的太阳总辐照度资料中1980年与1984年的两段数据做太阳振荡谱分析,对频谱进行等步长叠加证认的结果,除了得出l=0,1,2等低阶声模以外,还清楚地得出了以在对SMM资料的研究所未得到的l=3声波模式,而由相干及谱峰半宽,推出了低阶声模的相干时间即激发寿命近似为3至9天.另外,比较1980年与1984年两段数据的分析结果,发现太阳活动峰年1980年的模式频率比谷年1984年高出零点几至几个微赫兹(μHz),这意味着太阳短周期的振荡受长周期磁场变化的影响. 相似文献
8.
一个新型分米波太阳微耀斑现象的观测分析 总被引：1，自引：0，他引：1
本介绍一组短分米波（１．４２ＧＨｚ）太阳微耀斑的射电和光学辐射特征，它们包含３个叠加在连续辐射背景上的射电快速精细结构（ＦＦＳ），即准周期快速脉冲链（称微耀斑）它们的形态相似，强度大约在１５０－２００ｓｆｕ范围内，其寿命（半功率宽）大多为１５－５０ｍｓ，有１８个分离的双峰结构，该事件产生的７６４６活动区中出现两处新浮现的几个小黑子，呈现复杂极性，可能存在多重交叉小磁流环多次重联的复杂状况，本定 相似文献
9.
太阳和天体物理吸积盘中的场是一种空间间歇的磁流。在整个太阳上都可发现这种间歇磁流片，其中光球上90%以上的磁流呈现为强场形态，其强度为0.1-0.2T，大小为50-300km；在吸积盘中，已知脉动磁场比宏观磁场强几个数量级。磁场的重联湮灭，导致在薄电流片区形成小尺度的磁环胞以及同涨的横等离激元。磁流和等离激元之间的非线性相互作用引起自类似塌缩，形成更为空间间歇的塌缩的磁环元胞。而横等离激元诱发的自生磁场具有调制不稳定性，导致磁场塌缩，形成高度间歇的磁流。分别在磁流力学和等离子体动力论两种情况下，分析了这种磁塌缩不稳定性，并用于解释太阳上的间歇磁流以及寻求天体物理吸积盘中的反常粘滞。 相似文献
10.
利用线性状态空间模型（Ｌｉｎｅａｒ Ｓｔａｔｅ Ｓｐａｃｅ Ｍｏｄｅｌ－ＬＳＳＭ）,将 Ｃｙｇ Ｘ－１的功率谱分解为ＬＳＳＭ产生的模型功率谱和剩余功率谱两部分．集中分析剩余功率谱,结果显示, Ｃｙｇ Ｘ－１在低／硬态、转换态和高／软态三种状态的剩余功率谱有着不同的结构特征．其中高／软态和低／硬态的剩余功率谱存在一个宽峰结构,中心频率分别为～ ８ Ｈｚ和～ ５ Ｈｚ,低／硬态的剩余功率诺在～ ０．０７ Ｈｚ达到极大;转换态的剩余功率谱有双峰结构,其中心频率分别在～０．５—４Ｈｚ和～５—１１Ｈｚ,与我们以前分析的 ＱＰＯ的中心频率很接近,说明 ＱＰＯ与线性状态空间所要求的自回归模型可能属于不同的物理过程．与总功率谱比较,剩余功率谱对谱的变化部分（例如ＱＰＯ、截断频率等）更为敏感,本文对剩余功率谱中谱峰变化的原因做了初步的探讨． 相似文献
11.
High-quality stratospheric photographs in the continuum were used to investigate spatial scales of the solar granulation field. Two-dimensional intensity power spectra are shown to contain most frequently the modes corresponding to the sizes of granules, protogranules, mesogranules, and supergranules. The place of these four, the most steady formations of the quiet Sun in the global structure of the solar photosphere, is discussed as well as their interconnection and their relation to weak and strong magnetic fields. The protogranulation scale is argued to play an important role in organization of the fine structure of the photosphere and magnetic fields in the quiet and active regions of the Sun. 相似文献
12.
Hathaway D.H. Beck J.G. Bogart R.S. Bachmann K.T. Khatri G. Petitto J.M. Han S. Raymond J. 《Solar physics》2000,193(1-2):299-312
Spectra of the cellular photospheric flows are determined from observations acquired by the MDI instrument on the SOHO spacecraft. Spherical harmonic spectra are obtained from the full-disk observations. Fourier spectra are obtained from the high-resolution observations. The p-mode oscillation signal and instrumental artifacts are reduced by temporal filtering of the Doppler data. The resulting spectra give power (kinetic energy) per wave number for effective spherical harmonic degrees from 1 to over 3000. Significant power is found at all wavenumbers, including the small wavenumbers representative of giant cells. The time evolution of the spectral coefficients indicates that these small wavenumber components rotate at the solar rotation rate and thus represent a component of the photospheric cellular flows. The spectra show distinct peaks representing granules and supergranules but no distinct features at wavenumbers representative of mesogranules or giant cells. The observed cellular patterns and spectra are well represented by a model that includes two distinct modes – granules and supergranules. 相似文献
13.
We analyzed two sequences of quiet-Sun magnetograms obtained on June 4, 1992 and July 28, 1994. Both were observed during excellent seeing conditions such that the weak intranetwork (IN) fields are observed clearly during the entire periods. Using the local correlation tracking technique, we derived the horizontal velocity fields of IN and network magnetic fields. They consist of two components: (1) radial divergence flows which move IN fields from the network interior to the boundaries, and (2) lateral flows which move along the network boundaries and converge toward stronger magnetic elements. Furthermore, we constructed divergence maps based on horizonal velocities, which are a good representation of the vertical velocities of supergranules. For the June 4, 1992 data, the enhanced network area in the field of view has twice the flux density, 10% higher supergranular velocity and 20% larger cell sizes than the quiet, unenhanced network area. Based on the number densities and flow velocities of IN fields derived in this paper and a previous paper (Wang et al., 1995), we estimate that the lower limit of total energy released from the recycling of IN fields is 1.2 × 1028 erg s–1, which is comparable to the energy required for coronal heating. 相似文献
14.
An Evolving Synoptic Magnetic Flux map and Implications for the Distribution of Photospheric Magnetic Flux 总被引：1，自引：0，他引：1
We describe a procedure intended to produce accurate daily estimates of the magnetic flux distribution on the entire solar surface. Models of differential rotation, meridional flow, supergranulation, and the random emergence of background flux elements are used to regularly update unobserved or poorly observed portions of an initial traditional magnetic synoptic map that acts as a seed. Fresh observations replace model estimates when available. Application of these surface magnetic transport models gives us new insight into the distribution and evolution of magnetic flux on the Sun, especially at the poles where canopy effects, limited spatial resolution, and foreshortening result in poor measurements. We find that meridional circulation has a considerable effect on the distribution of polar magnetic fields. We present a modeled polar field distribution as well as time series of the difference between the northern and southern polar magnetic flux; this flux imbalance is related to the heliospheric current sheet tilt. We also estimate that the amount of new background magnetic flux needed to sustain the `quiet-Sun' magnetic field is about 1.1×1023 Mx d–1 (equivalent to several large active regions) at the spatial resolution and epoch of our maps. We comment on the diffusive properties of supergranules, ephemeral regions, and intranetwork flux. The maps are available on the NSO World Wide Web page. 相似文献
15.
Sara F. Martin 《Solar physics》1988,117(2):243-259
Network magnetic fields, ephemeral active regions, and intranetwork magnetic fields are illustrated and discussed in several contexts. First, they are presented in relation to the appearance and disappearance of magnetic flux. Second, their properties in common with all solar magnetic features are discussed. Third, their distinguishing characteristics are emphasized. Lastly, their interactions are illustrated.Network magnetic fields are no longer considered to be just the aged remnants of active regions. The network is the dynamic product of the merging and cancelling of intranetwork fields, ephemeral regions, and the remnants of active regions. Intranetwork fields are magnetic fields of mixed polarity that appear to originate continuously from localized source sites in between the network. The intranetwork magnetic fields are characterized by flow of successive fragments in approximately radial patterns away from their apparent source sites and by the relative weakness of their magnetic fields. Ephemeral active regions are small, new bipoles that grow as a unit or a succession of bipolar units and whose poles move in opposite directions from their apparent site of origin. Large ephemeral regions are not distinguishable from small active regions.Solar Cycle Workshop Paper. 相似文献
16.
Using high-resolution observations of deep magnetograms and H filtergrams obtained at Big Bear Solar Observatory during 17–24 October 1997, we have studied the interaction of intranetwork and network elements. The relationship between small-scale magnetic fields and active phenomena is investigated. Most of the small-scale active phenomena are triggered by the interaction either between intranetwork and network magnetic elements or among several network elements. The energy released due to the interaction of intranetwork–network elements and network–network elements is large enough to heat the corona. 相似文献
17.
Supergranule and Mesogranule Evolution 总被引：2，自引：0，他引：2
The MDI instrument on the SOHO satellite obtained a nearly continuous 45.5-hr run in high-resolution mode on 17–18 January 1997, collecting continuum, Dopplergram, and magnetogram images once per minute. This is one of the longest data sets yet obtained in this mode and shows significant evolution of the supergranulation pattern. After allowing for solar rotation within the fixed field of view, an area spanning 17° in latitude and 11° in longitude was extracted that covers the same area of the solar surface for the entire run. From the de-rotated continuum images, we computed flow maps of photospheric motions using local correlation techniques (LCT). Horizontal divergence maps constructed from the flow maps show local maxima of the size of mesogranules (5–10). We interpret these as mesogranules although the LCT flow map resolution (4.8 FWHM) may not completely resolve smaller mesogranules. Movies made from the divergence maps clearly show the outward convection (advection) of these mesogranules within each supergranule, and narrow boundaries of negative divergence outlining the supergranules. Several new supergranules are observed forming. These appear as areas of strong divergence that pop up between pre-existing supergranules and grow, pushing their neighbors apart. Others seem to perish between growing neighbors. We also computed the vertical component of vorticity from the flow maps. Movies of this vorticity do not show any obvious patterns. 相似文献
18.
High-resolution H filtergrams and deep magnetograms were obtained from the Big Bear Solar Observatory (BBSO) and Huairou Solar Observation Station (HSOS) during 17–24 October 1997. The three days (17, 18, and 19) with the best image quality were selected for this initial research. We have found that macrospicules are triggered by interaction either between intranetwork and network elements or among several network magnetic elements. We present a model to explain the spatial relationship between macrospicules and magnetic fields. 相似文献
19.
Results of a detailed study on supergranule lifetime and velocity fields are presented. We show the correlation between the observed downdraft velocity and the network magnetic flux elements on the quiet sun. After excluding areas with magnetic flux density 25 G, we find that the upper limit of the supergranule vertical speed is 0.1 km s–1 for both downdraft and updraft, and the r.m.s. speed is 0.03 km s–1. By observing the evolution of individual supergranules, we find that the average lifetime of supergranules might be 50 hours. We describe different ways of formation and decay of supergranular cells. New cells usually form in an area containing no pre-existing supergranule velocity fields. Cells may disappear in two ways: fragmentation and fading away. 相似文献
20.
A. H. Waelkens A. A. Schekochihin T. A. Enßlin 《Monthly notices of the Royal Astronomical Society》2009,398(4):1970-1988
We describe a novel technique for probing the statistical properties of cosmic magnetic fields based on radio polarimetry data. Second-order magnetic field statistics like the power spectrum cannot always distinguish between magnetic fields with essentially different spatial structure. Synchrotron polarimetry naturally allows certain fourth-order magnetic field statistics to be inferred from observational data, which lifts this degeneracy and can thereby help us gain a better picture of the structure of the cosmic fields and test theoretical scenarios describing magnetic turbulence. In this work we show that a fourth-order correlator of specific physical interest, the tension force spectrum, can be recovered from the polarized synchrotron emission data. We develop an estimator for this quantity based on polarized emission observations in the Faraday rotation free frequency regime. We consider two cases: a statistically isotropic field distribution, and a statistically isotropic field superimposed on a weak mean field. In both cases the tension force power spectrum is measurable; in the latter case, the magnetic power spectrum may also be obtainable. The method is exact in the idealized case of a homogeneous relativistic electron distribution that has a power-law energy spectrum with a spectral index of p = 3 , and assumes statistical isotropy of the turbulent field. We carry out numerical tests of our method using synthetic polarized emission data generated from numerically simulated magnetic fields. We show that the method is valid, that it is not prohibitively sensitive to the value of the electron spectral index p , and that the observed tension force spectrum allows one to distinguish between e.g. a randomly tangled magnetic field (a default assumption in many studies) and a field organized in folded flux sheets or filaments. 相似文献