共查询到19条相似文献，搜索用时 122 毫秒
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日冕物质抛射与太阳粒子事件 总被引：1，自引：0，他引：1
本文介绍了２０多年来对日冕物质抛射与太阳粒子事件的关系和太阳粒子事件的源等方面的研究成果和进展。大量的研究表明，太阳粒子事件源于日冕物质抛射并被日冕和行星际激波加速和控制。在无耀斑源的日冕和行星际激波加速和控制。只有极少数产生太阳粒子事件，并且这些事件中多数为低能粒子事件。这些相关日冕物质抛射的共同特征是：无相关的强Ｘ射线爆发，产生的行星际激波速度较快，无激波加速，无Ⅱ和Ⅳ米波爆发。几乎所有的产生 相似文献
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日冕物质抛射—空间天气的扰动源 总被引：5，自引：0，他引：5
日冕物质抛射是引起空间天气扰动的重要起因＿本文对日冕物质抛射的一般参量和形态、它与其它太阳活动现象的关系、它在行星际空间的表现以及它导致的地球空间环境扰动的研究进展作了介绍和讨论 相似文献
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本文对太阳活动区ＡＲ６８９１ 中两个暗条爆发的磁场环境、及爆发所引起的日地物理效应进行了比较和分析结果表明, 出现在靠近大尺度单极区的活动区暗条爆发, 可能导致较强烈的日冕物质抛射 相似文献
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在一维球坐标系下模拟了1998年11月4日至5日3个连续日冕物质抛射(CME)在行星际空间的传播和相互作用并最终形成“复杂抛射”的日地传输过程.首先在磁流体力学(MHD)数值模拟中应用Harten总变差减小(TVD)格式,通过调节计算模型中的引力无量纲参数α、等离子体参数β和气体多方指数γ,构造出数值计算所需的初态背景,使之在拉格朗日点处L1的太阳风速度vr、质子数密度Np及质子热压力与磁压力的比值βp与ACE卫星的观测数据一致.接着仅采用速度脉冲的扰动形式,其输入的幅度和持续时间由Lasco/C2、GOES、LEAR的观测数据并结合Michalek等提出的CME“锥模型”来确定.数值计算结果得到的两个激波到达时间和ACE卫星观测值的时间误差分别是3h和4h.这表明该模型能估算续发CME在行星际空间演化后驱动激波的到达时间和大致强度,在空间天气的激波到达时间的预报方面有潜在的应用价值. 相似文献
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本文统计了第２２ 太阳活动周期间（１９９１ ～１９９５ 年） 发生的２５ 个太阳质子事件与太阳耀斑及日冕物质抛射（ＣＭＥ） 事件的关系 统计结果表明, 所有的太阳质子事件都与耀斑发生相关, 除２ 个质子事件（１９９４１０２０ 和１９９５１０２０ 日发生的太阳质子事件） 与ＣＭＥ发生无关, 其余质子事件也都与ＣＭＥ 相关 值得注意的是, 与质子事件相关的耀斑有１６ 个是双带耀斑, 其中包括与ＣＭＥ无关的２ 个事件的耀斑, 占总数的６４ ％ 上述统计结果证实了无论是太阳耀斑, 还是物质抛射, 它们对太阳质子事件的发生同样起着非常重要的作用 相似文献
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日冕物质抛射（ＣＭＥ） 是一个极为复杂的动力学过程本文基于开放场、闭合场的物理条件及射电爆发理论, 研究了ＣＭＥｓ 与相伴随的射电Ⅱ型、Ⅲ型、Ⅳ型爆发、软χ射线增强及太阳耀斑的关系给出了它们相伴随的条件： 当磁通量喷发, 能量释放时, 等离子体将被加速如果加速区在开放场, 可能会产生Ⅲ型爆发; 如果是闭合场, 被加速的高能质子和高能电子将被磁环捕获高能质子在磁环腿部呈损失锥分布, 当Ｅ≥ＥＴ 时会产生软χ射线增强随着磁环内的热压Ｐ和磁压Ｐｍ 的升高, 当β≥βＴ 时, 磁环将炸裂, 产生ＣＭＥｓ抛射出的高能相对论电子绕开放场线作螺旋飞行时, 会产生Ⅳ型爆发; 而亚相对论电子以零入射角沿开放磁场线逃逸时, 会产生Ⅲ型爆发高速飞行的等离子体产生激波时, 会产生Ⅱ型爆发当ＣＭＥｓ 源接近耀斑时, 会触发耀斑爆发 相似文献
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《地球物理学进展》2016,(1)
日冕物质抛射(Coronal Mass Ejection,简称CME)可在短时间内将约1011~1013千克物质抛向行星际空间,是灾害性空间天气的主要驱动源之一.CME引发的空间天气事件可能会对卫星、航空器、航天器、电网、输油管道,以及航天员、航班机组人员和乘客健康造成严重危害.CME源区研究是理解CME的重要途径.本文旨在介绍近年来CME源区观测和理论研究进展,通过综合Hinode、STEREO、SDO等卫星的最新观测结果,对CME源区的观测特征进行描述;在此基础上,对stealth CME、twin-CME、大尺度活动等概念、观测现象背后的磁场机制、磁绳的观测和模拟,新的日冕磁场外推方法、CME的三维重构等进行概述.CME预报仍是目前空间天气领域的难点之一,结合最新观测数据对CME事件及其源区、尤其是源区大尺度磁场结构进行分析,对理解和预报CME及相关的空间天气事件具有重要意义. 相似文献
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《Journal of Atmospheric and Solar》2000,62(16):1457-1469
Coronal mass ejections (CMEs) are large-scale magnetized plasma structures ejected from closed magnetic field regions of the Sun. White light coronagraphic observations from ground and space have provided extensive information on CMEs in the outer corona. However, our understanding of the solar origin and early life of CMEs is still in an elementary stage because of lack of adequate observations. Recent space missions such as Yohkoh and Solar and Heliospheric Observatory (SOHO) and ground-based radioheliographs at Nobeyama and Nancay have accumulated a wealth of information on the manifestations of CMEs near the solar surface. We review some of these observations in an attempt to relate them to what we already know about CMEs. Our discussion relies heavily on non-coronagraphic data combined with coronagraphic data. Specifically, we discuss the following aspects of CMEs: (i) coronal dimming and global disk signatures, (ii) non-radial propagation during the early phase, (iii) Photospheric magnetic field changes during CMEs, and (iv) acceleration of fast CMEs. The relative positions and evolution of coronal dimming, arcade formation, prominence eruption will be discussed using specific events. The magnitude and spatial extent of CME acceleration may be an important parameter that distinguishes fast and slow CMEs. 相似文献
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Solar coronal mass ejections (CMEs) are a striking manifestation of solar activity seen in the solar corona, which bring out coronal plasma as well as magnetic flux into the interplanetary space and may cause strong interplanetary disturbances and geomagnetic storms. Understanding the initiation of CMEs and forecasting them are an important topic in both solar physics and geophysics. In this paper, we review recent progresses in research on the initiation of CMEs. Several initiation mechanisms and models are discussed. No single model/simulation is able to explain all the observations available to date, even for a single event. 相似文献
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We describe the world's largest synthesis radio telescope, the Very Large Array (VLA), and how it can be used to complement observations with the Solar and Heliospheric Observatory (SOHO) and the Yohkoh solar spacecraft. The VLA provides images with high spatial and temporal resolution, often across the visible solar disk. The VLA also detects nonthermal radiation that is not observed with SOHO and Yohkoh, and provides estimates for the coronal magnetic field strengths that are not directly measured by these spacecraft. The VLA data can be combined with SOHO CDS, SOHO EIT, or Yohkoh SXT observations to provide new insights to the compact, variable sources, called blinkers and bright points, in the solar transition region or low corona. A new 400 cm VLA system provides images of nonthermal burst activity associated with Coronal Mass Ejections (CMEs), and may detect thermal emission from CMEs, that can be compared with SOHO's LASCO and EIT instruments to obtain new information about the origin and evolution of CMEs. 相似文献
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对1970-1980年1AU附近太阳风的观测资料所进行的分析表明,60％的冕旒相关流和40％的CME相关云的流速都不大于350km/s;80％的流速不大于350km/s的低速风起源于冕旒,且除冕旒和CMEs外,看来还存在别的低速风日冕源区.有关冷风的分析表明,近80％的冷风的流速不大于350km/s,80％的冷风起源于冕旒;也有一小部分冷风既非起源于冕旒,也不起源于CMEs.低速风的11年变化显示,在太阳活动各位相,冕旒总是低速风的主要日冕源区.但是,极大位相时的冕旒宽度很可能大于极小和下降位相. 相似文献
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《Journal of Atmospheric and Solar》2000,62(16):1427-1435
Identifying coronal mass ejection (CME) precursors in the solar corona would be an important step in space weather forecasting, as well as a vital key to understanding the physics of CMEs. Twisted magnetic field structures are suspected of being the source of at least some CMEs. These features can appear sigmoid (S or inverse-S) shaped in soft X-ray (SXR) images. We review recent observations of these structures and their relation to CMEs, using SXR data from the Soft X-ray Telescope (SXT) on the Yohkoh satellite, and EUV data from the EUV Imaging Telescope (EIT) on the SOHO satellite. These observations indicate that the pre-eruption sigmoid patterns are more prominent in SXRs than in EUV, and that sigmoid precursors are present in over 50% of CMEs. These findings are important for CME research, and may potentially be a major component to space weather forecasting. So far, however, the studies have been subject to restrictions that will have to be relaxed before sigmoid morphology can be used as a reliable predictive tool. Moreover, some CMEs do not display a SXR sigmoid structure prior to eruption, and some others show no prominent SXR signature of any kind before or during eruption. 相似文献
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《Journal of Atmospheric and Solar》2000,62(16):1499-1507
It may be possible to calculate the rate of reconnection in the corona by measuring the rate at which the temporary coronal hole formed by a coronal mass ejection (CME) disappears. This calculation is possible if the disappearance of the hole is caused by the same reconnection process which creates the giant X-ray arches associated with CMEs. These arches form just below the vertical current sheet that is created as the CME drags magnetic field lines out into interplanetary space, and they are similar in form to ‘post’-flare loops, except that they often have an upward motion that is different. Instead of continually slowing with time as ‘post’-flare loops do, they move upwards at a rate which increases, or remains nearly constant, with time. This difference has raised doubts about the relevance of reconnection to the formation and propagation of the arches. Using a two-dimensional flux rope model to calculate the size and location of the current sheet as a function of time, we find that the difference between the motion of ‘post’-flare loops and giant arches can be explained simply by the variation of the coronal Alfvén speed with height. 相似文献
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《Journal of Atmospheric and Solar》2000,62(16):1545-1551
Transient large-scale emitting chains and threads, associated with several coronal mass ejections (CMEs), are analyzed by the SOHO/EIT, TRACE, Yohkoh/SXT, Nobeyama Radioheliograph, and some other imaging data. It is illustrated that a pronounced evolution of the chains and threads in the EUV, soft X-ray, microwave, and other ranges can occur many hours both before and after a CME on a considerable part of the solar visible disk, especially near the place of a CME eruption. Such relations between chains and CMEs seem to be plausible due to both phenomena being the consequences of the evolution of large-scale magnetic fields and have often a global character. 相似文献
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Geomagnetism and Aeronomy - Regularities in the formation of coronal mass ejections (CMEs) associated (Radio Loud, RL CME) and not associated (Radio Quiet, RQ CME) with type II radio bursts (RBIIs)... 相似文献