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1.
从理论和观测两个方面来介绍和讨论出现在太阳爆发过程中的磁重联电流片及其物理本质和动力学特征。首先介绍在理论研究和理论模型中,磁重联电流片是如何在爆发磁结构当中形成并发展的,对观测研究有什么指导意义。然后介绍观测工作是从哪几个方面对理论模型预测的电流片进行证认和研究的。第三,将介绍观测研究给出了哪些过去所没有能够预期的结果,这些结果对深入研究耀斑一CME电流片以及其中的磁重联过程的理论工作有什么重要的、挑战性的意义。第四,讨论最新的与此有关的理论研究和数值实验。最后,对未来的研究方向和重要课题进行综述和展望。 相似文献
2.
在本文中,我们对米波太阳射电爆发的观测和研究（Ｓｐｉｋｅｓ以及各类爆发）进行了较全面的总结,对Ｓｐｉｋｅｓ、米波射电爆发及基和太阳耀斑、ＣＭＥ（日冕物质抛射）的相互关系也给出了比较详细的讨论关加以概括;针对米波射电的未来观测和研究、米波Ｓｐｉｋｅｓ与广泛的其它太阳耀斑现象的米波射电爆发才耀斑及ＣＭＥ的关系和米波射电辐射的理论问题,在理论和观测两方面提出了未来工作的设想和建议。主要观战和结论有： 相似文献
3.
北京天文台对FFS事件的观测研究 总被引：1，自引：0，他引：1
从观测手段和取得的资料两个方面,评价了两个太阳峰年中北京天文台所观测到的太阳射电爆发中毫秒级快速精细结构（FFS）的观测结果．估计了新的观测仪器在第23周峰年将取得的观测结果．也讨论了在观测研究中值得重视的一些问题． 相似文献
4.
<正>太阳耀斑、暗条爆发以及日冕物质抛射(CME)对我们生存的空间环境有着重大影响.这些爆发所释放的能量储存在剪切的或扭曲的非势性磁场中.本论文对与太阳爆发有关的剪切磁场位型及其在爆发中的重要作用进行了深入系统的研究.这对理解和预言空间灾害性天气起着至关重要的作用.本论文的研究方法包括多波段观测(从个例的深入研究到大样本的统计分析)和数值模拟. 相似文献
5.
本文介绍了太阳射电Ⅱ型爆发中的一种独特的精细结构现象－频率分裂，并对它的观测特征和理论解释做了总结，最后，还对现存众多的理论模型逐一作了讨论。 相似文献
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太阳米波和分米波的射电观测是对太阳爆发过程中耀斑和日冕物质抛射现象研究的重要观测手段。米波和分米波的太阳射电暴以相干等离子体辐射为主导,表现出在时域和频域的多样性和复杂性。其中Ⅱ型射电暴是激波在日冕中运动引起电磁波辐射的结果。在Ⅱ型射电暴方面,首先对米波Ⅱ型射电暴的激波起源问题和米波Ⅱ型射电暴与行星际Ⅱ型射电暴的关系问题进行了讨论;其次,结合Lin-Forbes太阳爆发理论模型对Ⅱ型射电暴的开始时间和起始频率进行讨论:最后,对Ⅱ型射电暴信号中包含的两种射电精细结构,Herringbone结构(即鱼骨结构)和与激波相关的Ⅲ型射电暴也分别进行了讨论。Ⅲ型射电暴是高能电子束在日冕中运动产生电磁波辐射的结果。在Ⅲ型射电暴方面,首先介绍了利用Ⅲ型射电暴对日冕磁场位形和等离子体密度进行研究的具体方法;其次,对利用Ⅲ型射电暴测量日冕温度的最新理论进行介绍;最后,对Ⅲ型射电暴和Ⅱ型射电暴的时间关系、Ⅲ型射电暴和粒子加速以及Ⅲ型射电暴信号中包含的射电精细结构(例如斑马纹、纤维爆发及尖峰辐射)等问题进行讨论并介绍有关的最新研究进展。 相似文献
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这篇报告扼要地叙述了太阳耀斑硬X射线爆发的观测结果,着重介绍时间轮廓、能谱特征、X辐射的偏振以及硬X射线爆发源的位置和结构。全文共分六节,第一节简要地介绍太阳硬X射线爆发的观测史及“太阳峰年”卫星和“火鸟”卫星上的仪器,第二节描述两类太阳硬X射线爆发的特征,第三节描述能谱特征,第四节给出X辐射偏振的观测资料,第五节叙述太阳硬X射线源的位置和结构,最后,在第六节里提出我们对今后从事这项工作的看法。 相似文献
10.
七十年代以来的空间和地面观测表明,太阳耀斑是太阳大气中最剧烈的动力学过程。耀斑动力学的研究已成为当今太阳物理研究中重要的前沿课题之一.本文概要地介绍近年来在耀斑动力学过程的观测和理论方面的重要进展以及耀斑大气动力学的光谱诊断方法,并讨论了今后在观测和理论两方面的努力方向,为我国在即将到来的太阳22周峰年中的耀斑动力学研究提供参考. 相似文献
11.
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
12.
B. V. Somov 《Astronomy Letters》2010,36(7):514-519
In connection with the RHESSI satellite observations of solar flares, which have revealed new properties of hard X-ray sources
during flares, we offer an interpretation of these properties. The observed motions of coronal and chromospheric sources are
shown to be the consequences of three-dimensional magnetic reconnection at the separator in the corona. During the first (initial)
flare phase, the reconnection process releases an excess of magnetic energy related predominantly to themagnetic tensions
produced before the flare by shear plasma flows in the photosphere. The relaxation of a magnetic shear in the corona also
explains the downward motion of the coronal source and the decrease in the separation between chromospheric sources. During
the second (main) flare phase, ordinary reconnection dominates; it describes the energy release in the terms of the “standard
model” of large eruptive flares accompanied by the rise of the coronal source and an increase in the separation between chromospheric
sources. 相似文献
13.
The relationship between the velocity of CMEs and the plasma temperature of the associated X-ray solar flares is investigated.The velocity of CMEs increases with plasma temperature(R=0.82)and photon index below the break energy(R=0.60)of X-ray flares.The heating of the coronal plasma appears to be significant with respect to the kinetics of a CME from the reconnection region where the flare also occurs.We propose that the initiation and velocity of CMEs perhaps depend upon the dominant process of conversion of the magnetic field energy of the active region to heating/accelerating the coronal plasma in the reconnected loops.Results show that a flare and the associated CME are two components of one energy release system,perhaps,magnetic field free energy. 相似文献
14.
Jun LinHarvard-Smithsonian Center for Astrophysics Garden Street Cambridge MA USA 《中国天文和天体物理学报》2002,2(6)
Based on previous work, we investigate the propagation of CMEs in a more realistic plasma environment than the isothermal atmosphere, and find that it is a slightly faster reconnection for flux ropes to break free. The average Alfven Mach number MA for the inflow into the reconnection site has to be at least 0.013 in order to give a plausible eruption (compared to MA = 0.005 for the isothermal atmosphere). Taking MA = 0.1, we find that the energy output and the electric field induced inside the current sheet match the temporal behavior inferred from the energetic, long duration, CME-associated X-ray events. The results indicate that catastrophic loss of equilibrium in the coronal magnetic field provides the most promising mechanism for major solar eruptions, and that the more energetic the eruption is, the earlier the associated flare peaks. The variation of the output power with the background field strength revealed by our calculations implies the poor correlation between slow CMEs and solar flares. Th 相似文献
15.
Kazunari Shibata 《Astrophysics and Space Science》1998,264(1-4):129-144
The solar X-ray observing satellite Yohkoh has discovered various new dynamic features in solar flares and corona, e.g., cusp-shaped
flare loops, above-the-loop-top hard X-ray sources, X-ray plasmoid ejections from impulsive flares, transient brightenings
(spatially resolved microflares), X-ray jets, large scale arcade formation associated with filament eruption or coronal mass
ejections, and so on. It has soon become clear that many of these features are closely related to magnetic reconnection. We
can now say that Yohkoh established (at least phenomenologically) the magnetic reconnection model of flares. In this paper,
we review various evidence of magnetic reconnection in solar flares and corona, and present unified model of flares on the
basis of these new Yohkoh observations.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
16.
Maria D. Kazachenko Richard C. Canfield Dana W. Longcope Jiong Qiu 《Solar physics》2012,277(1):165-183
In order to better understand the solar genesis of interplanetary magnetic clouds (MCs), we model the magnetic and topological
properties of four large eruptive solar flares and relate them to observations. We use the three-dimensional Minimum Current Corona model (Longcope, 1996, Solar Phys.
169, 91) and observations of pre-flare photospheric magnetic field and flare ribbons to derive values of reconnected magnetic
flux, flare energy, flux rope helicity, and orientation of the flux-rope poloidal field. We compare model predictions of those
quantities to flare and MC observations, and within the estimated uncertainties of the methods used find the following: The
predicted model reconnection fluxes are equal to or lower than the reconnection fluxes inferred from the observed ribbon motions.
Both observed and model reconnection fluxes match the MC poloidal fluxes. The predicted flux-rope helicities match the MC
helicities. The predicted free energies lie between the observed energies and the estimated total flare luminosities. The
direction of the leading edge of the MC’s poloidal field is aligned with the poloidal field of the flux rope in the AR rather
than the global dipole field. These findings compel us to believe that magnetic clouds associated with these four solar flares
are formed by low-corona magnetic reconnection during the eruption, rather than eruption of pre-existing structures in the
corona or formation in the upper corona with participation of the global magnetic field. We also note that since all four
flares occurred in active regions without significant pre-flare flux emergence and cancelation, the energy and helicity that
we find are stored by shearing and rotating motions, which are sufficient to account for the observed radiative flare energy
and MC helicity. 相似文献
17.
L.M. Green S.A. Matthews L. van Driel-Gesztelyi L.K. Harra J.L. Culhane 《Solar physics》2002,205(2):325-339
Developments in our knowledge of coronal mass ejections (CMEs) have shown that many of these transients occur in association with solar flares. On the occasions when there is a common occurrence of the eruption and the flare, it is most likely that the flare is of high intensity and/or long-duration (Burkepile, Hundhausen, and Webb, 1994; Munro et al., 1979; Webb and Hundhausen, 1987). A model for the relationship between the long-duration event and eruption has been developed (Carmichael, 1964; Sturrock, 1966; Hirayama, 1974; Kopp and Pneuman, 1976), but not so for the high-intensity flares and eruptions. This work investigates the magnetic topology changes that occur for a X1.2 GOES classification flare which has no associated CME. It is found that the flare is likely to result from the interaction between two pre-existing loops low in the corona, producing a confined flare. Slightly higher in the corona, a loop is observed which exhibits an outward motion as a result of the reconfiguration during reconnection. The objective of this work is to gain insight on the magnetic topology of the event which is critical in order to determine whether a high-intensity flare is likely to be related to a CME or not. 相似文献
18.
Based on our previous works regarding solar eruptions, we focus on the relationships among different eruptive phenomena, such
as solar flares, eruptive prominences and coronal mass ejections (CMEs). The three processes show clear correlations under
certain circumstances. The correlation between a CME and solar flare depends the energy that stored in the relevant magnetic
structure, which is available to drive the eruption: the more energy that is stored, the better the correlation is; otherwise,
the correlation is poor. The correlation between a CME and eruptive prominence, on the other hand, depends on the plasma mass
concentration in the configuration prior to the eruption: if the mass concentration is significant, a CME starts with an eruptive
prominence, otherwise, a CME develops an without an apparent associated eruptive prominence. These results confirm that solar
flares, eruptive prominences and CMEs are different significances of a single physical process that is related to the energy
release in a disrupted coronal magnetic field. The impact of gravity on CME propagation and the above correlations is also
investigated. Our calculations indicate that the effect of gravity is not significant unless the strength of the background
field in the disrupted magnetic configuration becomes weak, say weaker than 30 G. 相似文献
19.
We review recent progress on our understanding of radio emission from solar flares and coronal mass ejections (CMEs) with emphasis on those aspects of the subject that help us address questions about energy release and its properties, the configuration of flare?–?CME source regions, coronal shocks, particle acceleration and transport, and the origin of solar energetic particle (SEP) events. Radio emission from electron beams can provide information about the electron acceleration process, the location of injection of electrons in the corona, and the properties of the ambient coronal structures. Mildly relativistic electrons gyrating in the magnetic fields of flaring loops produce radio emission via the gyrosynchrotron mechanism, which provides constraints on the magnetic field and the properties of energetic electrons. CME detection at radio wavelengths tracks the eruption from its early phase and reveals the participation of a multitude of loops of widely differing scale. Both flares and CMEs can ignite shock waves and radio observations offer the most robust tool to study them. The incorporation of radio data into the study of SEP events reveals that a clear-cut distinction between flare-related and CME-related SEP events is difficult to establish. 相似文献
20.
A topological model with magnetic reconnection at two separators in the corona is used to account for the recently discovered changes of the photospheric magnetic field in the active region NOAA 9077 during the July 14, 2000 flare. The model self-consistently explains the following observed effects: (1) the magnetic field strength decreases on the periphery of the active region but increases in its inner part near the neutral line of the photospheric magnetic field; (2) the center-of-mass positions of the fields of opposite (northern and southern) polarities converge; and (3) the magnetic flux of the active region decreases after the flare. The topological model gives not only a qualitative interpretation of the flare phenomena (the structure of the interacting magnetic fluxes in the corona, the location of the energy sources, the shape of the flare ribbons and kernels in the chromosphere and photosphere), but also correct quantitative estimates of the large-scale processes that form the basis for solar flares. The electric field emerging in the flare during large-scale reconnection is calculated. The electric field strength correlates with the observed intensity of the hard X-ray bremsstrahlung, suggesting an electron acceleration as a result of reconnection. 相似文献