共查询到20条相似文献，搜索用时 31 毫秒
1.
Reliable information on the distribution of magnetic fields across the whole surface of the Sun is urgently needed to predict conditions in the solar corona, in the interplanetary medium, and in the near-Earth space (space weather). Several space- and ground-based solar instruments currently provide full-disk magnetograms. However, these measurements sometimes differ very significantly, which makes a cross-calibration of different datasets and searching for the reasons for such differences a very crucial task. Here, we analyze the Huairou Solar Observing Station (HSOS) Solar Magnetism and Activity Telescope (SMAT) full-disk line-of-sight magnetograms in comparison with magnetograms taken at the Solar Dynamic Observatory/Helioseismic and Magnetic Imager (SDO/HMI) and Solar Telescope for Operative Predictions (STOP) instruments. We show systematic differences between original SMAT magnetograms and those of other telescopes. The differences are caused by some SMAT instrumental problems, which we investigate. We suggest methods for compensating for these effects that have improved the quality of SMAT magnetograms. These methods will enable us to use SMAT measurements to solve many solar physics problems that are related to studying global solar magnetism and space weather. 相似文献
2.
R. Brajša S. Pohjolainen V. Ruždjak T. Sakurai S. Urpo B. Vršnak H. Wöhl 《Solar physics》1996,163(1):79-91
Measurements of the Sun in the near-infrared He i 10830 Å absorption line were performed using the echelle spectrograph with a dispersion of 6.71 mÅ per pixel at the Vacuum Tower Telescope (German Solar Telescopes, Teide Observatory, Izaña, Tenerife, Spain) on May 26, 1993. These measurements were compared with full-disc soft X-ray images of the Sun (Japanese solar satellite Yohkoh), full-disc solar images in H (Big Bear Solar Observatory), full-disc solar images in the He i 10830 Å line (National Solar Observatory, Kitt Peak) and with full-disc microwave solar maps at 37 GHz (Metsähovi Radio Research Station). In the He 10830 Å line the Sun displays a limb darkening similar to that in the visible part of the spectrum. Active regions and H filaments show a strong absorption in the He 10830 Å line, whereas the absorption is weak in coronal holes. 相似文献
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磁场是太阳物理的第1观测量,当前太阳磁场观测研究正迈向大视场、高时空分辨率、高偏振测量精度以及空间观测的时代.中国首颗太阳观测卫星—先进天基太阳天文台(ASO-S)也配置了具有高时空分辨率、高磁场灵敏度的全日面矢量磁像仪(FMG)载荷,针对FMG载荷的需求,讨论了大面阵、高帧频互补金属氧化物半导体(Complementary Metal Oxide Semiconductor, CMOS)图像传感器应用于太阳磁场观测的可行性.首先,基于滤光器型太阳磁像仪观测的原理,比较分析了目前CMOS图像传感器(可用的或是可选的两种快门模式)的特点,指出全局快门类型更适合FMG;其次搭建了CMOS传感器实验室测试系统,测量了CMOS图像传感器的像素增益及其分布规律;最后在怀柔太阳观测基地的全日面太阳望远镜上开展了实测验证,获得预期成果.在这些研究基础上,形成了FMG载荷探测器选型方向. 相似文献
5.
O.V.Chumak 《中国天文和天体物理学报》2003,3(2):175-182
We present a study of the relationship between integral area and corresponding total magnetic flux for solar active regions. It is shown that some of these relationships are satisfied to simple power laws. Fractal examination showed that some of these power laws can not be justified inside the simple models of stationary magnetic flux tube aggregation. All magnetic fluxes and corresponding areas were calculated using the data measured with the Solar Magnetic Field Telescope of the Huairou Solar Observing Station in Beijing. 相似文献
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Hong-Qi Zhang Xing-Ming Bao Yin Zhang Ji-Hong Liu Shu-Dong Bao Yuan-Yong Deng Wei Li Jie Chen Jin-Ping Dun Jiang-Tao Su Juan Guo Xiao-Fan Wang Ke-Liang Hu Gang-Hua Lin Dong-Guang WangNational Astronomical Observatories Chinese Academy of Sciences Beijing 《中国天文和天体物理学报》2003,3(6):491-494
We analyze the magnetic configurations of three super active regions, NOAA 10484, 10486 and 10488, observed by the Huairou Multi-Channel Solar Telescope (MCST) from 2003 October 18 to November 4. Many energetic phenomena, such as flares (including a X-28 flare) and coronal mass ejections (CMEs), occurred during this period. We think that strong shear and fast emergence of magnetic flux are the main causes of these events. The question is also of great interest why these dramatic eruptions occurred so close together in the descending phase of the solar cycle. 相似文献
8.
Xing-Ming Bao Hong-Qi ZhangNational Astronomical Observatories Chinese Academy of Sciences Beijing baoxm@sunlO.bao.ac.cn 《中国天文和天体物理学报》2003,3(1):87-97
We observed the line-of-sight magnetic field in the chromosphereand photosphere of a large quiescent filament on the solar disk on September 6, 2001 using the Solar Magnetic Field Telescope in Huairou Solar Observing Station. The chromospheric and photospheric magnetograms together with Hβ filtergrams of the filament were examined. The filament was located on the neutral line of the large scale longitudinal magnetic field in the photosphere and the chromosphere. The lateral feet of the filament were found to be related to magnetic structures with opposite polarities. Two small lateral feet are linked to weak parasitic polarity. There is a negative magnetic structure in the photosphere under a break of the filament. At the location corresponding to the filament in the chromospheric magnetograms, the magnetic strength is found to be about 40-70 Gauss (measuring error about 39 Gauss). The magnetic signal indicates the amplitude and orientation of the internal magnetic field in the filament. We discuss several possible causes which may produce such a measured signal. A twisted magnetic configuration inside the filament is suggested . 相似文献
9.
S. Liu 《Astrophysics and Space Science》2014,351(2):409-416
Magnetic fields dominate most solar activities, there exist direct relations between solar flare and the distributions of magnetic field, and also its corresponding magnetic energy. In this paper, the statistical results about the relationships between the spatial magnetic field and solar flare are given basing on vector magnetic field observed by the Solar Magnetic Field Telescope (SMFT) at Huairou Solar Observing Station (HSOS). The spatial magnetic fields are obtained by extrapolated photosphere vector magnetic field observed by SMFT. There are 23 active regions with flare eruption are chosen as data samples, which were observed from 1997 to 2007. The results are as follows: 1. Magnetic field lines become lower after flare for 16 (69 %) active regions; 2. The free energy are decreased after flare for 17 (74 %) active regions. It can conclude that for most active regions the changes of magnetic field after solar flare re coincident with the previous observations and studies. 相似文献
10.
P. J. Crockett D. B. Jess M. Mathioudakis F. P. Keenan 《Monthly notices of the Royal Astronomical Society》2009,397(4):1852-1861
Magnetic bright points (MBPs) in the internetwork are among the smallest objects in the solar photosphere and appear bright against the ambient environment. An algorithm is presented that can be used for the automated detection of the MBPs in the spatial and temporal domains. The algorithm works by mapping the lanes through intensity thresholding. A compass search, combined with a study of the intensity gradient across the detected objects, allows the disentanglement of MBPs from bright pixels within the granules. Object growing is implemented to account for any pixels that might have been removed when mapping the lanes. The images are stabilized by locating long-lived objects that may have been missed due to variable light levels and seeing quality. Tests of the algorithm, employing data taken with the Swedish Solar Telescope, reveal that ≈90 per cent of MBPs within a 75 × 75 arcsec2 field of view are detected. 相似文献
11.
H. Q. Zhang 《Astrophysics and Space Science》2006,305(3):211-224
We discuss the study of solar magnetic fields based on the photospheric vector magnetograms of solar active regions which were obtained at Huairou Solar Observing Station near Beijing in the period of 22nd and 23th solar cycles. The measurements of the chromospheric magnetic field and the spatial configuration of the field at the lower solar atmosphere inferred by the distribution of the solar photospheric and chromospheric magnetic field. After the analysis on the formation process of delta configuration in some super active regions based on the photospheric vector magnetogram observations, some results are obtained: (1) The analysis of magnetic writhe of whole active regions cannot be limited in the strong field of sunspots, because the contribution of the fraction of decayed magnetic field is non-negligible. (2) The magnetic model of kink magnetic ropes, proposed to be generated in the subatmosphere, is not consistent with the evolution of large-scale twisted photospheric transverse magnetic field and the relationship with magnetic shear in some delta active regions completely. (3) The proposition is that the large-scale delta active regions are formed from contribution by highly sheared non-potential magnetic flux bundles generated in the subatmosphere. We present some results of a study of the magnetic helicity. We also compare these results with other data sets obtained by magnetographs (or Stokes polarimeters) at different observatories, and analyze the basic chirality of the magnetic field in the solar atmosphere. 相似文献
12.
Radio observations of some active regions (ARs) obtained with the Nobeyama radioheliograph at λ=1.76cm are used for estimating the magnetic field strength in the upper chromosphere, based on thermal bremsstrahlung. The results are compared with the magnetic field strength in the photosphere from observations with the Solar Magnetic Field Telescope (SMFT) at Huairou Solar Observing Station of Beijing Astronomical Observatory. The difference in the magnetic field strength between the two layers seems reasonable. The solar radio maps of active regions obtained with the Nobeyama radioheliograph, both in total intensity (I-map) and in circular polarizations (V-map), are compared with the optical magnetograms obtained with the SMFT. The comparison between the radio map in circular polarization and the longitudinal photospheric magnetogram of a plage region suggest that the radio map in circular polarization is a kind of magnetogram of the upper chromosphere. The comparison of the radio map in total intensity with the photospheric vector magnetogram of an AR shows that the radio map in total intensity gives indications of magnetic loops in the corona, thus we have a method of defining the coronal magnetic structure from the radio I-maps at λ=1.76 cm. Analysing the I-maps, we identified three components: (a) a compact bright source; (b) a narrow elongated structure connecting two main magnetic islands of opposite polarities (observed in both the optical and radio magnetograms); (c) a wide, diffuse, weak component that corresponds to a wide structure in the solar active region which shows in most cases an S or a reversed S contour, which is probably due to the differential rotation of the Sun. The last two components suggest coronal loops on different spatial scales above the neutral line of the longitudinal photospheric magnetic field. 相似文献
13.
On 13 May 2000 parts of a penumbra were observed in an active region NOAA 8990 with the La Palma Stokes Polarimeter attached
to the Swedish Vacuum Solar Telescope. The stratification over the solar atmosphere of different physical parameters is retrieved
from these data by using the Stokes inversion based on response functions. The results confirm the previous findings of the
penumbral structure. In general, the magnetic field becomes weaker and more horizontal with increasing distance from the umbra
and the line-of-sight velocities are increasing towards the outer boundary of the penumbra. The results also suggest the existence
of the unresolved fine structure of the penumbra. The stratifications of the temperature and of the magnetic field strength
indicate the presence of rising flux tubes, which were predicted theoretically by Schlichenmaier, Jahn and Schmidt (1998,
Astron. Astrophys.
337, 897). 相似文献
14.
用口径为１０ｃｍ的全日面磁场望远镜，我们获得了光球的全日面视向磁场观测资料。与３５ｃｍ磁场望远镜的观测结果比对，发现日面上各活动区磁场的形态以及强度都吻合较好，说明全日面磁场望远镜得到的观测资料是可信的。 相似文献
15.
We use 270 pairs of vector magnetograms observed by Haleakala Stokes Polarimeter (HSP) and Solar Magnetic Field Telescope
(SMFT) of Huairou Solar Observing Station from 1997 to 2000 to compare current helicity derived by these two instruments.
We apply the same approach to both data sets to resolve 180∘ azimuth ambiguity and compute α coefficient of linear force-free field. After careful consideration of various aspects of
both data sets, we find that in ≈80% of cases SMFT and HSP data result in the same sign of α, and the Pearson linear correlation
coefficient between two data sets is rp = 0.64.
Operated by the Association of Universities for Research in Astronomy (AURA, Inc) under cooperative agreement with the National
Science Foundation (NSF). 相似文献
16.
We summarize studies of helical properties of solar magnetic fields such as current helicity and twist of magnetic fields in solar active regions (ARs), that are observational tracers of the alpha-effect in the solar convective zone (SCZ). Information on their spatial distribution is obtained by analysis of systematic mag-netographic observations of active regions taken at Huairou Solar Observing Station of National Astronomical Observatories of Chinese Academy of Sciences. The main property is that the tracers of the alpha-effect are antisymmetric about the solar equator. Identifying longitudinal migration of active regions with their individual rotation rates and taking into account the internal differential rotation law within the SCZ known from helioseismology, we deduce the distribution of the effect over depth. We have found evidence that the alpha-effect changes its value and sign near the bottom of the SCZ, and this is in accord with the theoretical studies and numerical simulations. We discuss 相似文献
17.
Li Feng Hui Li Bernd Inhester Bo Chen Bei-Li Ying Lei Lu Weiqun Gan 《天文和天体物理学研究(英文版)》2019,(4):109-118
The Advanced Space-based Solar Observatory(ASO-S) mission aims to explore the two most spectacular eruptions on the Sun: solar flares and coronal mass ejections(CMEs), and their magnetism.For the study of CMEs, the payload Lyman-alpha Solar Telescope(LST) has been proposed. It includes a traditional white-light coronagraph and a Lyman-alpha coronagraph which opens a new window to CME observations. Polarization measurements taken by white-light coronagraphs are crucial for deriving fundamental physical parameters of CMEs. To make such measurements, there are two options for a Stokes polarimeter which have been applied by existing white-light coronagraphs for space missions. One uses a single or triple linear polarizer, the other involves both a half-wave plate and a linear polarizer. We find that the former option is subject to less uncertainty in the derived Stokes vector propagating from detector noise.The latter option involves two plates which are prone to internal reflections and may have a reduced transmission factor. Therefore, the former option is adopted as our Stokes polarimeter scheme for LST. Based on the parameters of the intended linear polarizer(s) colorPol provided by CODIXX and the half-wave plate 2-APW-L2-012 C by Altechna, it is further shown that the imperfect maximum transmittance of the polarizer significantly increases the variance amplification of Stokes vector by at least about 50% when compared with the ideal case. The relative errors of Stokes vector caused by the imperfection of colorPol polarizer and the uncertainty due to the polarizer assembly in the telescope are estimated to be about 5%. Among the considered parameters, we find that the dominant error comes from the uncertainty in the maximum transmittance of the polarizer. 相似文献
18.
A. M. Broomhall W. J. Chaplin Y. Elsworth R. New 《Monthly notices of the Royal Astronomical Society》2009,397(2):793-801
Birmingham Solar Oscillations Network (BiSON) instruments use resonant scattering spectrometers to make unresolved Doppler velocity observations of the Sun. Unresolved measurements are not homogenous across the solar disc and so the observed data do not represent a uniform average over the entire surface. The influence on the inhomogeneity of the solar rotation and limb darkening has been considered previously and is well understood. Here, we consider a further effect that originates from the instrumentation itself. The intensity of light observed from a particular region on the solar disc is dependent on the distance between that region on the image of the solar disc formed in the instrument and the detector. The majority of BiSON instruments have two detectors positioned on opposite sides of the image of the solar disc and the observations made by each detector are weighted towards differing regions of the disc. Therefore, the visibility and amplitudes of the solar oscillations and the realization of the solar noise observed by each detector will differ. We find that the modelled bias is sensitive to many different parameters such as the width of solar absorption lines, the strength of the magnetic field in the resonant scattering spectrometer, the orientation of the Sun's rotation axis, the size of the image observed by the instrument and the optical depth in the vapour cell. We find that the modelled results best match the observations when the optical depth at the centre of the vapour cell is 0.55. The inhomogeneous weighting means that a 'velocity offset' is introduced into unresolved Doppler velocity observations of the Sun, which varies with time, and so has an impact on the long-term stability of the observations. 相似文献
19.
Zhong-Quan Qu Shuai Wang Cheng-Lin Xu XiaoYu Zhang Ming-Guo Sun Chun-Lan Jin National Astronomical Observatories/Yunnan Astronomical Observatory Chinese Academy of Sciences Kunming zqqu@vip.km.net Graduate School of the Chinese Academy of Sciences Beijing 《中国天文和天体物理学报》2005,5(4):426-432
We analyze the spectral line broadening of those magneto-sensitive lines in solar magnetized atmospheres. The broadening at the line wings is due to the increase of the effective width of energy levels involved in Zeeman splitting, and the broadening at the line core also originated in Zeeman splitting under the condition that the Zeeman components are mixed. Therefore, the magnetoinduced or Zeeman broadening take effects on the whole line. The observed Stokes parameter data in a sunspot and outside it acquired by Solar Stokes Spectrum Telescope (S3T) are analyzed for the demonstration of this mechanism, and the Zeeman broadening rates are calculated for FeI6302.5 under some assumptions. Our result shows that the broadening is increased as the magnetic field strength becomes stronger, but the rate of increase at the line core is decreased as the field strength increases, while the rate at the wing does not show such an obvious regularity. The broadening is more effective in the line core than in the wings. 相似文献
20.
S. Tsuneta K. Ichimoto Y. Katsukawa S. Nagata M. Otsubo T. Shimizu Y. Suematsu M. Nakagiri M. Noguchi T. Tarbell A. Title R. Shine W. Rosenberg C. Hoffmann B. Jurcevich G. Kushner M. Levay B. Lites D. Elmore T. Matsushita N. Kawaguchi H. Saito I. Mikami L. D. Hill J. K. Owens 《Solar physics》2008,249(2):167-196
The Solar Optical Telescope (SOT) aboard the Hinode satellite (formerly called Solar-B) consists of the Optical Telescope Assembly (OTA) and the Focal Plane Package (FPP). The OTA is a 50-cm diffraction-limited
Gregorian telescope, and the FPP includes the narrowband filtergraph (NFI) and the broadband filtergraph (BFI), plus the Stokes
Spectro-Polarimeter (SP). The SOT provides unprecedented high-resolution photometric and vector magnetic images of the photosphere
and chromosphere with a very stable point spread function and is equipped with an image-stabilization system with performance
better than 0.01 arcsec rms. Together with the other two instruments on Hinode (the X-Ray Telescope (XRT) and the EUV Imaging Spectrometer (EIS)), the SOT is poised to address many fundamental questions
about solar magnetohydrodynamics. This paper provides an overview; the details of the instrument are presented in a series
of companion papers.
M. Otsubo is a former NAOJ staff scientist. 相似文献