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冕洞的研究在近二十多年里取得了丰硕的成果。本文回顾了冕洞的发现及观测历史，系统阐述了冕洞的结构特征、形成及演化规律，讨论了冕洞对日地空间产生的影响，冕洞与超级活动区的关系以及冕洞在太阳活动预报中所起的作用，在此基础上利用１９７０—１９９５年的冕洞资料对冕洞的时空分布和磁极性演化规律与太阳活动周的关系，以及冕洞与太阳风速度、地磁扰动等方面进行分析研究，得出以下结论：（１）冕洞在南北半球的分布在形态上基本是对称的，但在冕洞数量上北半球稍占优势；（２）冕洞的盛衰演化呈周期性，表现为赤道冕洞周期与黑子周期是完全一致的，极冕洞周期与黑子周期相位相差１８０°；（３）赤道冕洞的纬度分布随太阳活动周上升而上升，当太阳活动周达到极大值时，它也达到极大，然后再随太阳活动周下降而下降，极冕洞的纬度延伸方向演化与赤道冕洞相反；（４）极冕洞的极场呈１１年周期性，并且极场反转出现在太阳活动峰年期间；（５）太阳风和地磁扰动与冕洞的演化有着密切的关系 相似文献
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冕洞的研究在近二十多年里取得了丰硕的成果。本文回顾了冕洞的发现及观测历史，系统阐述了冕洞的结果特征，形成及演化规律，讨论了冕洞对日地空间产生的影响，冕洞与超级活动区的关系以及冕洞在太阳活动预报中所起的作用，在此基础上利用１９７０－１９９５年的晚洞资料听时空分 布和磁极性演化规律与太阳活动区的关系以及冕洞的时空分布和磁极性演化 规律与太阳活性周的得出以下结论：（１）冕洞在南北半球的分布在形态上基本是 相似文献
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本文用1970－1995年的冕洞资料，分析了冕洞的分布规律，磁场极性的演化特征和冕洞的地磁效应，以及它们与太阳黑子周期的演化关系，得到了一些有意义的结论。特别指出赤道冕洞和极区冕洞具有相反的演化规律和不同的特征。 相似文献
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冕洞边界区磁结构的探讨—Ⅱ.太阳活动20,21周的冕洞及其边界区磁结构的变 总被引：3，自引：0，他引：3
本文分析讨论了太阳活动２０、２１周的冕洞及其边界区磁结构的变化，它包括：冕洞区光球磁场强度、磁极性的变化；冕洞面积与高速太阳风风速的关系，冕洞边界周围的环境，重点探讨太阳活动下降，极小相低纬，赤道冕洞区与其边界区磁结构的变化。 相似文献
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分析了２２太阳活动周（１９８６．１—１９９５．６；ＣＲ１７７１—ＣＲ１８９８）冕洞对地磁扰动的长期效应和短期效应。作为长期效应，赤道冕洞数和面积指数随太阳活动周的演化与同期的地磁Ａｐ指数的长期变化基本一致，二者在α＝０．０１的信度水平上密切相关，表明赤道冕洞不仅对低年的磁扰有贡献，而且对峰年期间地磁扰动的贡献也是不可忽视的。对冕洞的短期地磁效应的研究表明，不论哪种类型的冕洞，在它们过中经后的１—４天，地磁Ａｐ指数都有不同程度的增长；大冕洞比小冕洞引起的地磁效应较强烈；跨越赤道的冕洞比未跨越赤道的同级冕洞引起的地磁效应较强烈 相似文献
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本文分析讨论了太阳活动２０、２１周的冕洞及其边界区磁结构的变化。它包括：冕洞区光球磁场强度、磁极性的变化；冕洞面积与高速太阳风风速的关系；冕洞边界周围的环境。重点探讨太阳活动下降、极小相低纬、赤道冕洞区与其边界区磁结构的变化。 相似文献
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本文对２２太阳活动周以来的中低纬冕洞和地磁指数Ａｐ进行了统计。对以月，年及２２周以来不同时段冕洞和地磁指数的时段合成图进行了分析。 相似文献
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简要介绍了在１９８８－１９９５年期间冕洞观测研究的主要进展。文中共分五个方面：１．冕洞磁场观测研究的新进展；２．冕洞在太阳活动周不同位相时的规律性；３．冕洞区高速太阳风观测的新结果；４．冕洞加热问题；５．存在问题。 相似文献
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V. M. Malashchuk G. V. Rudenko N. N. Stepanian V. G. Fainshtein 《Bulletin of the Crimean Astrophysical Observatory》2011,107(1):60-66
By means of comparison of the positions of 665 observed coronal holes (CHs) and the structures of the magnetic field at different
heights, it was shown that 43% of the observed CHs are not associated with unipolar regions of the background field at the
photosphere. With height increasing from 1 to 2.5 solar radii, the structure of the magnetic field varies in 57% of all CHs.
In 16% of the cases, variations of the structure can be observed at heights as small as 2500–10 000 km. Comparison of the
positions of CHs with the longitudinal distribution of long-lived +/− and −/+ boundaries of the large-scale structure of the
magnetic field at all the heights was carried out. It was shown that CHs adjoin or intersect with the Hale boundaries half
as often as with those having the opposite distribution of the fields at both sides of the boundary. These results attest
to a closer connection between the CHs and the photospheric and subphotospheric fields than with coronal fields. The magnetic
fields of coronal structures can shield the coronal holes, thus creating “closed” CHs with a limited output of high-speed
solar wind streams. 相似文献
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We present identifications of coronal holes (CHs) from observations in the He?i 10?830 Å line made at Kitt Peak Observatory (from 1975 to 2003) and in the EUV 195 Å wavelength with SOHO/EIT (from 1996 to 2012). To determine whether a feature is a CH we have developed semi-automatic techniques for delineating CH borders on synoptic charts and for subsequent mapping of these borders on magnetic-field charts. Using these techniques, we superimposed CH borders on magnetic-field charts over the time interval from 1975 to 2012. A major contribution to the total area was made by high-latitude CHs, but in the declining phase of solar cycle 23, the contribution from low-latitude CHs increased substantially. Variations in the flux of Galactic cosmic rays and those in the inclination angle of the heliospheric current sheet followed the cyclic variations of CH areas. High-latitude CHs affect the properties of the solar wind in the ecliptic plane. 相似文献
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Yunhee Choi Y.-J. Moon Seonghwan Choi Ji-Hye Baek Sungsoo S. Kim K.-S. Cho G. S. Choe 《Solar physics》2009,254(2):311-323
We have examined the relationships among coronal holes (CHs), corotating interaction regions (CIRs), and geomagnetic storms in the period 1996?–?2003. We have identified 123 CIRs with forward and reverse shock or wave features in ACE and Wind data and have linked them to coronal holes shown in National Solar Observatory/Kitt Peak (NSO/KP) daily He i 10?830 Å maps considering the Sun?–?Earth transit time of the solar wind with the observed wind speed. A sample of 107 CH?–?CIR pairs is thus identified. We have examined the magnetic polarity, location, and area of the CHs as well as their association with geomagnetic storms (Dst≤?50 nT). For all pairs, the magnetic polarity of the CHs is found to be consistent with the sunward (or earthward) direction of the interplanetary magnetic fields (IMFs), which confirms the linkage between the CHs and the CIRs in the sample. Our statistical analysis shows that (1) the mean longitude of the center of CHs is about 8°E, (2) 74% of the CHs are located between 30°S and 30°N (i.e., mostly in the equatorial regions), (3) 46% of the CIRs are associated with geomagnetic storms, (4) the area of geoeffective coronal holes is found to be larger than 0.12% of the solar hemisphere area, and (5) the maximum convective electric field E y in the solar wind is much more highly correlated with the Dst index than any other solar or interplanetary parameter. In addition, we found that there is also a semiannual variation of CIR-associated geomagnetic storms and discovered new tendencies as follows: For negative-polarity coronal holes, the percentage (59%; 16 out of 27 events) of CIRs associated with geomagnetic storms in the first half of the year is much larger than that (25%; 6 out of 24 events) in the second half of the year and the occurrence percentage (63%; 15 out of 24 events) of CIR-associated storms in the southern hemisphere is significantly larger than that (26%; 7 out of 27 events) in the northern hemisphere. Positive-polarity coronal holes exhibit an opposite tendency. 相似文献
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The parameters of the magnetic flux distribution inside low-latitude coronal holes (CHs) were analyzed. A statistical study of 44 CHs based on Solar and Heliospheric Observatory (SOHO)/MDI full disk magnetograms and SOHO/EIT 284?Å images showed that the density of the net magnetic flux, B net, does not correlate with the associated solar wind speeds, V x . Both the area and net flux of CHs correlate with the solar wind speed and the corresponding spatial Pearson correlation coefficients are 0.75 and 0.71, respectively. A possible explanation for the low correlation between B net and V x is proposed. The observed non-correlation might be rooted in the structural complexity of the magnetic field. As a measure of the complexity of the magnetic field, the filling factor, f(r), was calculated as a function of spatial scales. In CHs, f(r) was found to be nearly constant at scales above 2 Mm, which indicates a monofractal structural organization and smooth temporal evolution. The magnitude of the filling factor is 0.04 from the Hinode SOT/SP data and 0.07 from the MDI/HR data. The Hinode data show that at scales smaller than 2 Mm, the filling factor decreases rapidly, which means a multifractal structure and highly intermittent, burst-like energy release regime. The absence of the necessary complexity in CH magnetic fields at scales above 2 Mm seems to be the most plausible reason why the net magnetic flux density does not seem to be related to the solar wind speed: the energy release dynamics, needed for solar wind acceleration, appears to occur at small scales below 1 Mm. 相似文献
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Coronal holes (CHs) are regions of open magnetic field lines in the solar corona and the source of the fast solar wind. Understanding the evolution of coronal holes is critical for solar magnetism as well as for accurate space weather forecasts. We study the extreme ultraviolet (EUV) synoptic maps at three wavelengths (195 Å/193 Å, 171 Å and 304 Å) measured by the Solar and Heliospheric Observatory/Extreme Ultraviolet Imaging Telescope (SOHO/EIT) and the Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA) instruments. The two datasets are first homogenized by scaling the SDO/AIA data to the SOHO/EIT level by means of histogram equalization. We then develop a novel automated method to identify CHs from these homogenized maps by determining the intensity threshold of CH regions separately for each synoptic map. This is done by identifying the best location and size of an image segment, which optimally contains portions of coronal holes and the surrounding quiet Sun allowing us to detect the momentary intensity threshold. Our method is thus able to adjust itself to the changing scale size of coronal holes and to temporally varying intensities. To make full use of the information in the three wavelengths we construct a composite CH distribution, which is more robust than distributions based on one wavelength. Using the composite CH dataset we discuss the temporal evolution of CHs during the Solar Cycles 23 and 24. 相似文献
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通过对１２－２２周（（１８７８－１９９５年）太阳大黑子群分布南北半球不对称的整体特征的研究,探讨了太阳活动周的长期演化趋势．约定Ｎ与Ｓ分别表示北南半球大黑子群数之和,ＢＮ与ＢＳ为北南半球大黑子群的纬度和．由这４个物理量定义了太阳活动周的３个参量：（１）太阳活动不对称指数ＡＳ＝（Ｎ－Ｓ）／（Ｎ＋Ｓ）;（２）平均纬度ＢＴ＝（ＢＮ＋ＢＳ）／（Ｎ＋Ｓ）,ＢＳ取负值;（３）太阳活动带的宽度ＢＷ＝ＢＮ／Ｎ－ＢＳ／Ｓ．对上述１１个活动周,得到了有关８０年周期的性质及奇偶数周大黑子群数变化的有意义的统计结果． 相似文献
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QIAN Ya-wen FENG Song DENG Lin-hua LIU Wei-hang 《Chinese Astronomy and Astrophysics》2019,43(3):365-374
The study on the 1.3–1.7 yr period of the solar and geomagnetic activities is very important for understanding the possible physical processes in the solar-terrestrial coupling system. The sunspot is the most prominent magnetic field structure in the solar photosphere, and the Ap index is an important indicator for the global geomagnetic activity level. The 1.3–1.7 yr period for the sunspot number and the geomagnetic Ap index is obtained by the synchro-squeezing wavelet transform, and the phase relationship between them is studied by the cross-correlation analysis. The main results are as follows: (1) The 1.3–1.7 yr period of the geomagnetic Ap index and sunspot number exhibits an intermittent evolutionary characteristics, and changes continuously with the time; (2) the geomagnetic Ap index has a higher periodic component in the odd solar cycles than the neighboring even solar cycles, which is characterized by fluctuations; (3) the phase relationship between the geomagnetic Ap index and the sunspot number is not always invariant, in most cases the geomagnetic Ap index lags behind the sunspot number, except in the 18th and 22th solar cycles. 相似文献
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K. Wilhelm L. Abbo F. Auch��re N. Barbey L. Feng A. H. Gabriel S. Giordano S. Imada A. Llebaria W. H. Matthaeus G. Poletto N.-E. Raouafi S. T. Suess L. Teriaca Y.-M. Wang 《Astronomy and Astrophysics Review》2011,19(1):1-70
Coronal plumes, which extend from solar coronal holes (CH) into the high corona and??possibly??into the solar wind (SW), can now continuously be studied with modern telescopes and spectrometers on spacecraft, in addition to investigations from the ground, in particular, during total eclipses. Despite the large amount of data available on these prominent features and related phenomena, many questions remained unanswered as to their generation and relative contributions to the high-speed streams emanating from CHs. An understanding of the processes of plume formation and evolution requires a better knowledge of the physical conditions at the base of CHs, in plumes and in the surrounding inter-plume regions. More specifically, information is needed on the magnetic field configuration, the electron densities and temperatures, effective ion temperatures, non-thermal motions, plume cross sections relative to the size of a CH, the plasma bulk speeds, as well as any plume signatures in the SW. In spring 2007, the authors proposed a study on ??Structure and dynamics of coronal plumes and inter-plume regions in solar coronal holes?? to the International Space Science Institute (ISSI) in Bern to clarify some of these aspects by considering relevant observations and the extensive literature. This review summarizes the results and conclusions of the study. Stereoscopic observations allowed us to include three-dimensional reconstructions of plumes. Multi-instrument investigations carried out during several campaigns led to progress in some areas, such as plasma densities, temperatures, plume structure and the relation to other solar phenomena, but not all questions could be answered concerning the details of plume generation process(es) and interaction with the SW. 相似文献