共查询到20条相似文献，搜索用时 31 毫秒
1.
Jun Lin 《中国天文和天体物理学报》2007,7(4):457-476
Large-scale magnetic structures are the main carrier of major eruptions in the solar atmosphere. These structures are rooted in the photosphere and are driven by the unceas-ing motion of the photospheric material through a series of equilibrium configurations. The motion brings energy into the coronal magnetic field until the system ceases to be in equilib-rium. The catastrophe theory for solar eruptions indicates that loss of mechanical equilibrium constitutes the main trigger mechanism of major eruptions, usually shown up as solar flares, eruptive prominences, and coronal mass ejections (CMEs). Magnetic reconnection which takes place at the very beginning of the eruption as a result of plasma instabilities/turbulence inside the current sheet, converts magnetic energy into heating and kinetic energy that are responsible for solar flares, and for accelerating both plasma ejecta (flows and CMEs) and energetic particles. Various manifestations are thus related to one another, and the physics behind these relationships is catastrophe and magnetic reconnection. This work reports on re- cent progress in both theoretical research and observations on eruptive phenomena showing the above manifestations. We start by displaying the properties of large-scale structures in the corona and the related magnetic fields prior to an eruption, and show various morphological features of the disrupting magnetic fields. Then, in the framework of the catastrophe theory, we look into the physics behind those features investigated in a succession of previous works, and discuss the approaches they used. 相似文献
2.
Cheng Fang School of Astronomy Space Science Nanjing University Nanjing China Key Laboratory of Modern Astronomy Astrophysics Ministry of Education 《中国天文和天体物理学报》2011,(12)
Owing to the largely improved facilities and working conditions,solar physics research in China has recently shown marked development.This paper reports on the recent progress of solar physics research in Mainland China,mainly focusing on several hot issues,including instrumentations,magnetic field observations and research,solar flares,filaments and their eruptions,coronal mass ejections and related processes,as well as active regions and the corona,small-scale phenomena,solar activity and its predictions.... 相似文献
3.
Chen Zhang Shuang-Nan Zhang 《中国天文和天体物理学报》2009,9(3)
High angular resolution X-ray imaging is always useful in astrophysics and solar physics. In principle, it can be performed by using coded-mask imaging with a very long mask-detector distance. Previously, the diffraction-interference effect was thought to degrade coded-mask imaging performance dramatically at the low energy end with its very long mask-detector distance. The diffraction-interference effect is described with numerical calculations, and the difffraction-interference cross correlation reconstruction method (DICC) is developed in order to overcome the imaging performance degradation. Based on the DICC, a super-high angular resolution principle (SHARP) for coded-mask X-ray imaging is proposed. The feasibility of coded mask imaging beyond the diffraction limit of a single pinhole is demonstrated with simulations. With the specification that the mask element size is 50 × 50 μm2 and the mask-detector distance is 50 m, the achieved angular resolution is 0.32arcsec above about 10keV and 0.36arcsec at 1.24keV (λ = 1 nm), where diffraction cannot be neglected. The on-axis source location accuracy is better than 0.02 arcsec. Potential applications for solar observations and wide-field X-ray monitors are also briefly discussed. 相似文献
4.
This paper is part I of a limited review of the applications of the spectral theory of linear operators in an astrophysical context. The ideal magnetohydrodynamic equations arise in the study of magnetic flux tubes in the solar corona, and in the plasma physics of nuclear containment devices. The system described by these equations is very rich both mathematically and physically, and there are many open problems associated with these models. The underlying mathematical principles are discussed in a qualitative manner in Paper I, and in a more technical manner in subsequent Paper II. 相似文献
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6.
Solar Maximum Mission 总被引：1，自引：0，他引：1
J. David Bohlin Kenneth J. Frost Peter T. Burr Arun K. Guha George L. Withbroe 《Solar physics》1980,65(1):5-14
7.
太阳物理学中的分形和混沌 总被引：1，自引：0，他引：1
对非线性科学的两个重要分支；分形和混沌在太阳物理学中的应用情况作了综述信要内容包括；太阳活动混沌性的揭示；对太阳活动混沌性的可能解释－太阳非线性发电机理论；一些太阳现象的分形描述；耀斑的自组织临界行为研究，最后给出了作者对这一领域工作前景的展望。 相似文献
8.
R. N. Bracewell 《Solar physics》1988,117(2):261-267
The discovery of 680-million year old varves by George Williams in South Australia, recording several millennia of fossil solar cycles, is a most exciting development that is bound to make an impact on solar physics. Already new problems of physical understanding have been posed by the 315-year Elatina cycle and the separate 350-year cycle, or undulation (Williams, 1985, 1986; Williams and Sonett, 1985). The Elatina cycle evidences itself multiplicatively in the form of amplitude modulation with a distinctive nonsinusoidal envelope, while the undulation is additive and quasisinusoidal (Bracewell and Williams, 1986). Both of these periodic phenomena are present in historical records of sunspots, but would not have been discerned from modern solar observations, which do not date back far enough. The explanation of two such sharply defined periods, in addition to the less sharply defined 22-year magnetic cycle, will require an understanding of solar physics that we do not yet have. Examples of the impact that the varve discovery is beginning to make are given, and a previously proposed mechanism for driving the activity cycle is extended in terms of a magnetic wave propagated radially outward from a deep torsional oscillator.Invited Talk to the 2nd Solar Cycle Workshop. 相似文献
9.
Juan Zhao Yan-Ben Han Zhi-An LiDepartment of Astronomy Beijing Normal University Beijing zj@bnu.edu.cnNational Astronomical Observatories Chinese Academy of Sciences Beijing 《中国天文和天体物理学报》2004,4(2):189-197
Using continuous wavelet transform, we examine the relationship between solar activity and the annual precipitation in the Beijing area. The results indicate that the annual precipitation is closely related to the variation of sunspot numbers, and that solar activity probably plays an important role in influencing the precipitation on land. 相似文献
10.
Kunitomo Sakurai 《Astrophysics and Space Science》1974,28(2):375-519
This paper discusses solar cosmic ray phenomena and related topics from the solar physical point of view. Basic physics of the solar atmosphere and solar flare phenomena are, therefore, considered in some detail. Since solar cosmic rays are usually produced by solar flares, we must first understand the processes and mechanism of solar flares, especially the so-called proton flares, in order to understand the acceleration mechanism of solar cosmic rays and their behaviour in both the solar atmosphere and interplanetary space. For this reason, detailed discussion is given on various phenomena associated with solar flares, proton flare characteristics, and the mechanism of solar flares.Since the discovery of solar cosmic rays by Forbush, the interplanetary space has been thought of as medium in which solar cosmic rays propagate. In this paper, the propagation of solar cosmic rays in this space is, therefore, discussed briefly by referring to the observed magnetic properties of this space. Finally, some problems related to the physics of galactic cosmic rays are discussed.Astrophysics and Space Science Review Paper. 相似文献
11.
Fundamental advances in the physics of the solar corona from the 1960's to the present time are briefly reviewed. Progress in coronal investigations has mainly been associated with major space missions, which have discovered such new phenomena as coronal holes and coronal mass ejections, and have enabled detailed study of coronal arch systems. The role of magnetic fields on various scales in quasi-steady-state phenomena is discussed for various phases of the solar activity cycle. 相似文献
12.
Dramatic extensions of experimental possibilities (spacecraft RHESSI, CORONAS-F and others) in solar gamma-ray astronomy call for urgent, detailed theoretical consideration of a set of physical problems of solar activity and solar-terrestrial relationships that earlier may have only been outlined. Here we undertake a theoretical analysis of issues related to the production of gamma-radiation in the processes of interactions of energetic (accelerated) heavy and middle nuclei with the nuclei of the solar atmosphere (the so-called i-j interactions). We also make an estimate of the contribution of these interactions to the formation of nuclear and isotopic abundances of the solar atmosphere in the range of light and rare elements. The analysis is carried out for solar flares in the wide range of their intensities. We compare our theoretical estimates with RHESSI observations for the flare of 2002 July 23. It was shown that the 24Mg gamma-ray emission in this event was produced by the newly generated Mg nucle 相似文献
13.
This paper will review the input of 65 years of radio observations to our understanding of solar and solar–terrestrial physics. It is focussed on the radio observations of phenomena linked to solar activity in the period going from the first discovery of the radio emissions to present days. We shall present first an overview of solar radio physics focussed on the active Sun and on the premices of solar–terrestrial relationships from the discovery to the 1980s. We shall then discuss the input of radioastronomy both at metric/decimetric wavelengths and at centimetric/millimetric and submillimetric wavelengths to our understanding of flares. We shall also review some of the radio, X-ray and white-light signatures bringing new evidence for reconnection and current sheets in eruptive events. The input of radio images (obtained with a high temporal cadence) to the understanding of the initiation and fast development in the low corona of coronal mass ejections (CMEs) as well as the radio observations of shocks in the corona and in the interplanetary medium will be reviewed. The input of radio observations to our knowledge of the interplanetary magnetic structures (ICMEs) will be summarized; we shall show how radio observations linked to the propagation of electron beams allow to identify small scale structures in the heliosphere and to trace the connection between the Sun and interplanetary structures as far as 4AU. We shall also describe how the radio observations bring useful information on the relationship and connections between the energetic electrons in the corona and the electrons measured in-situ. The input of radio observations on the forecasting of the arrival time of shocks at the Earth as well as on Space Weather studies will be described. In the last section, we shall summarize the key results that have contributed to transform our knowledge of solar activity and its link with the interplanetary medium. In conclusion, we shall indicate the instrumental radio developments at Earth and in space, which are from our point of view, necessary for the future of solar and interplanetary physics. 相似文献
14.
Barbara J. Thompson Sarah E. Gibson Peter C. Schroeder David F. Webb Charles N. Arge Mario M. Bisi Giuliana de Toma Barbara A. Emery Antoinette B. Galvin Deborah A. Haber Bernard V. Jackson Elizabeth A. Jensen Robert J. Leamon Jiuhou Lei Periasamy K. Manoharan M. Leila Mays Patrick S. McIntosh Gordon J. D. Petrie Simon P. Plunkett Liying Qian Peter Riley Steven T. Suess Munetoshi Tokumaru Brian T. Welsch Thomas N. Woods 《Solar physics》2011,274(1-2):29-56
We present an overview of the data and models collected for the Whole Heliosphere Interval, an international campaign to study the three-dimensional solar?Cheliospheric?Cplanetary connected system near solar minimum. The data and models correspond to solar Carrington Rotation 2068 (20 March??C?16 April 2008) extending from below the solar photosphere, through interplanetary space, and down to Earth??s mesosphere. Nearly 200 people participated in aspects of WHI studies, analyzing and interpreting data from nearly 100 instruments and models in order to elucidate the physics of fundamental heliophysical processes. The solar and inner heliospheric data showed structure consistent with the declining phase of the solar cycle. A closely spaced cluster of low-latitude active regions was responsible for an increased level of magnetic activity, while a highly warped current sheet dominated heliospheric structure. The geospace data revealed an unusually high level of activity, driven primarily by the periodic impingement of high-speed streams. The WHI studies traced the solar activity and structure into the heliosphere and geospace, and provided new insight into the nature of the interconnected heliophysical system near solar minimum. 相似文献
15.
Richard F. Donnelly 《Solar physics》1987,109(1):37-58
Several progressions in the temporal characteristics of full-disk solar UV and EUV fluxes have been identified that raise many questions about the solar physics involved. The collective effect of numerous enhancements smaller than scaled plages contribute significantly to the solar cycle variations, especially for emissions from the cooler portions of the corona and the chromosphere. Active-region remnants are suggested to have a strong role even in solar-rotation induced variations late in an episode of major activity. Although cool coronal EUV emissions are long lasting, the persistence of the solar-rotation induced variations is even greater at photospheric UV wavelengths. Gyroresonance and possibly nonthermal radio emission at centimeter wavelengths are suggested to be particularly important during the first solar rotation of an episode of major activity. 相似文献
16.
Richard F. Donnelly 《Solar physics》1971,109(1):37-58
Several progressions in the temporal characteristics of full-disk solar UV and EUV fluxes have been identified that raise many questions about the solar physics involved. The collective effect of numerous enhancements smaller than scaled plages contribute significantly to the solar cycle variations, especially for emissions from the cooler portions of the corona and the chromosphere. Active-region remnants are suggested to have a strong role even in solar-rotation induced variations late in an episode of major activity. Although cool coronal EUV emissions are long lasting, the persistence of the solar-rotation induced variations is even greater at photospheric UV wavelengths. Gyroresonance and possibly nonthermal radio emission at centimeter wavelengths are suggested to be particularly important during the first solar rotation of an episode of major activity. 相似文献
17.
18.
Can Asymmetry of Solar Activity be Extended into Extended Cycle？ 总被引：1，自引：0，他引：1
With the use of the Royal Greenwich Observatory data set of sunspot groups,an attempt is made to examine the north-south asymmetry of solar activity in the “extended” solar cycles. It is inferred that the asymmetry established for individual solar cycles does not extend to the “extended” cycles. 相似文献
19.
Gui-Ming LeNational Astronomical Observatories Chinese Academy of Sciences Beijing Center for Space Science Applied Research Center Chinese Academy of Sciences Beijing 《中国天文和天体物理学报》2004,4(6):578-582
Properties of the Schwabe cycles in solar activity are investigated by using wavelet transform. We study the main range of the Schwabe cycles of the solar activity recorded by relative sunspot numbers, and find that the main range of the Schwabe cycles is the periodic span from 8-year to 14-year. We make the comparison of 11-year‘s phase between relative sunspot numbers and sunspot group numbers. The results show that there is some difference between two phases for the interval from 1710 to 1810, while the two phases are almost the same for the interval from 1810 to 1990. 相似文献
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