日冕物质抛射的对地有效性和近地空间环境的研究

作为灾害性空间天气的一种重要志源——日冕物质抛射(CME),一直是空间物理学家关注和研究的热点;另一方面,做为空间天气的最直接表现的层次——近地空间环境,随着地基探测手段的不断建立和完善也成为日-地关系链研究中的一个重要方面.主要从空间天气这因果两端出发,对CME的对地有效性问题,以及近地空间环境的探测和动力学过程进行了初步研究.在CME的对地有效性方面,主要工作包括:(1)CME冰淇淋锥模型的建立;(2)分析了CME对地有效性的主要影响因素;(3)分析了CME对地有效性的特大地磁暴起因.在近地空间环境研究方面,主要工作包括:(1)参与建立了中国科学技术大学米-瑞利-钠荧光激光雷达,并给出其对80~110km高度钠层的初步观测结果;(2)利用流星雷达研究了中高层大气周日、半日潮汐的典型相关模式.     

侦测太阳风暴

2003年10月19日，太阳表面爆发一个巨大的太阳耀斑，同时三个巨大的太阳黑子群引起科学家们的注意，它们在此后的两个星期中共产生了124个太阳耀斑，其中三个是有记录以来最大的耀斑。伴随着电磁辐射的喷发，随之而来的是被称为日冕物质抛射(CME）的巨大的磁化等离子体云，这些不可预知的等离子体云由数十亿     

程鑫：追逐太阳狂暴之谜

正太阳让地球拥有了一片欣欣向荣的景色,但在更近的观察距离上它却具有狂暴的一面。它的外层——日冕,是一个炎热且充满活力的地方,在那里会不断发出带电粒子流形成太阳风,更会有太阳系中最大尺度的爆发现象——日冕物质抛射(CME)发生。CME发生时,数十亿吨磁化等离子体爆炸喷发的物质会对地球产生     

太阳光球磁场和磁活动现象

概述了太阳磁场和太阳上几种常见的几种磁活动现象:光球层的黑子、色球层的耀斑、日珥和暗条,以及日冕层的日冕物质抛射.介绍了这些磁活动现象的国内外研究概况.     

日地系统扰动多层次综合研究

本文介绍对日地系统扰动作多层次综合研究所取得的最新成果,分析了磁暴形态类型对行星际扰动结构,包括激波、高密度结构、强磁场结构、高速流等的响应特征,讨论了磁暴主相形成、延迟和消隐,及初相形成的条件,发现了行星际强磁场膨胀结构的动力学效应,及新的亚阿尔文波速流事例。     

环状日冕物质抛射事件的数值模拟

在对二维理想磁流体力学方程组采用多步隐格式进行数值处理后，利用长时间渐近方法计算得到了太阳风的盔状流动解。并以较切合实际的解作为背景初态，对盔状冕流底部磁通量喷发的大气响应进行了数值模拟。结果表明：在新的扰动磁场作用下，原冕流底部的物质将受到压缩并向上运动，形成高密度亮环结构，在环的下方出现低密度暗腔；在环的顶部向外运动过程的同时，其足部几乎保持不动。模拟结果再现了环状日冕物质抛射的主要观测特征。数值结果还表明了向外流动的太阳风，有助于环状高密度结构向行星际空间传播，并得到了与观测结果相近的环的运动速度。     

磁层亚暴面临的难题及研究方向

文章就磁层亚暴研究中遇到的问题,包括对其整体过程,行星际磁场南北方向 分量的起源,对行星际条件影响的定量关系,太阳风驱动过程,膨胀相触发区的位置, 以及与磁暴的关系等作了叙述。同时,作者还指出了今后的研究方向。     

天医携手 悬壶问天——昆明医科大学附一院联手中科院云南天文台研究空间天气对人体活动影响

<正>太阳是离地球最近的恒星,孕育了地球上的生命,不断带给我们光和热。但是太阳活动也给人类的生产生活带来了许多负面影响,例如:干扰卫星通信,影响电力传输等。同时人体健康也受到太阳活动影响,研究表明当太阳活动中日冕物质抛射物(CME)影响地球磁场时会有心脑血管疾病和精神疾病的发病率有上升趋势。国际上通过观测CME影响宇宙线流量的现象——福布希下降(Forbush Decrease)来预警心脑血管疾病发生时间,获得了12小时的预警时间。     

太阳日冕爆发现象的观测研究

<正>太阳日冕爆发现象的观测研究项目利用最优秀的、涵盖从光球到日冕的多台地、空基太阳望远镜的观测资料,开展了多种太阳日冕爆发事件的观测研究,研究成果主要集中在以下5个方面:1.详细研究了几个暗条不稳定性事件及相应的光球磁活动,并强调指出,由暗条     

深空探索

太阳耀斑触发机制研究中国科学院紫金山天文台“太阳活动的多波段观测研究”团组为光球剪切运动触发耀斑及磁内爆猜想提供了新证据。相关成果发表于《天体物理学杂志快报》（The Astrophysical Journal Letters）。太阳耀斑,以及日冕物质抛射和暗条爆发,被认为是太阳大气中同一种爆发现象的不同表现形式。研究团队基于太阳动力学天文台（SDO）的大气成像仪（AIA）以及日震磁像仪（HMI）数据,研究了2013年8月17日位于活动区11818的一个M3.3级耀斑。本次事件展示了太阳大气中不同高度的相互磁作用,     

Solar Coronal Mass Ejection as a Result of Magnetic Helicity Accumulation in the Corona

Coronal mass ejections（CMEs） are a major form of solar activities.A CME takes away 10^15-16 g of plasma from solar low corona,to disturb the near-Earth space if the CME direction is favorable.Here we summarize our understandings and reasoning that lead us to conclude that CMEs are the unavoidable products of magnetic helicity accumulation in the corona.Our study puts the formation of magnetic flux ropes and CME eruptions as natural and unavoidable results of coronal evolution.     

Relativistic solar cosmic rays

Solar and galactic cosmic rays are of profound astrophysical interest. One facet of contemporary cosmic ray research utilizes these energetic particles as space probes for studying the characteristics of the solar-controlled interplanetary medium, the heliosphere, which is essentially the extension of the solar corona to a considerable distance beyond the orbit of earth. Solar cosmic ray observations in particular contribute to our understanding of the earth's environs, the interplanetary medium, and the sun itself. Appropriately deployed ground-based cosmic ray detectors utilize the earth as a spacedraft for carrying out experiments that are far beyond the capacity of artificial satellites. In interpreting the observations, however, the effects of the geomagnetic field and of the atmosphere must be taken into account by appropriate analytical procedures. Theoretical models account for many of the characteristics of the observed modulations and anisotropies, which manifest themselves as temporal or spatial intensity variations. Analysis of the measurements in terms of various models provides an understanding of the physical mechanisms, as well as the determination of the relevant parameters. Properties of solar cosmic rays that have been investigated include spectra, angular distributions, transport mechanisms and the acceleration to relativistic energies.     

Equatorial aurora: the aurora-like airglow in the negative magnetic anomaly

The most fantastic optical phenomena in the Earth''s upper atmosphere are the auroras. They are highly informative indicators of solar activity, geomagnetic activity, upper atmospheric structures and dynamics, and magnetospheric energetic particles. An area where the geomagnetic field differs significantly from the expected symmetric dipole, such as at the South Atlantic Anomaly, where the magnetic field intensity is low, gives rise to stronger precipitation of energetic particles into the upper atmosphere. Impact excitation and the subsequent airglow emissions exhibit aurora-like dynamic signatures. Nomenclatures of nonpolar aurora or equatorial auroras are similar to those used with the polar auroras owing to their similar excitation mechanisms. This paper provides an overview of the knowledge and the challenges concerning auroral activity at the South Atlantic Anomaly, or more generally, at the negative magnetic anomaly. We emphasize systematic investigation of the equatorial auroras to reveal the temporal and spatial evolution of the magnetic anomaly and the behaviour of energetic particles in near-Earth space.     

On the origin of microbial magnetoreception

A broad range of organisms, from prokaryotes to higher animals, have the ability to sense and utilize Earth''s geomagnetic field—a behavior known as magnetoreception. Although our knowledge of the physiological mechanisms of magnetoreception has increased substantially over recent decades, the origin of this behavior remains a fundamental question in evolutionary biology. Despite this, there is growing evidence that magnetic iron mineral biosynthesis by prokaryotes may represent the earliest form of biogenic magnetic sensors on Earth. Here, we integrate new data from microbiology, geology and nanotechnology, and propose that initial biomineralization of intracellular iron nanoparticles in early life evolved as a mechanism for mitigating the toxicity of reactive oxygen species (ROS), as ultraviolet radiation and free-iron-generated ROS would have been a major environmental challenge for life on early Earth. This iron-based system could have later been co-opted as a magnetic sensor for magnetoreception in microorganisms, suggesting an origin of microbial magnetoreception as the result of the evolutionary process of exaptation.     

用三维运动学模型研究行星际激波与共转高速流的相互作用

利用三维运动学模型模拟研究行星际激波与共转高速流(CHSS)的相互作用。通过改变模式输入条件中耀斑的强度及位置,研究相互作用对CHSS到达地球时间的影响,以及对激波的传播和激波形态的影响。模拟结果表明:(1)行星际激波与CHSS相互作用对彼此到达地球时间都有影响;(2)有激波比没有激波条件下的CHSS到达地球时间要早,且CHSS到达地球时间与驱动激波的耀斑的强度以及扰动源区的位置有关,耀斑的强度越大、扰动源区与CHSS前的电流片的经度距离越近,则CHSS到达地球时间也越早;(3)激波在以CHSS为背景的太阳风中传播比在没有CHSS的均匀背景场中传播得快,但激波与CHSS的相互作用对激波到达地球时间的影响远没有对CHSS到达地球时间的影响大;(4)当耀斑位于CHSS前电流片的东边时,耀斑驱动的激波与CHSS相互作用可能会使激波形态发生改变,呈双峰结构。     

一个交叉研究领域——动物地磁导航的研究进展

地磁场在一些动物的长距离迁徙等活动中扮演着定向和导航作用。本 文以鸟类为例 ，详细介绍动物地磁导航研究的主要进展，指出地磁场在鸟类归巢和迁徙活动中发挥重要的 “罗盘”作用。同时提出当前地磁导航研究中迫切需要解决的两个问题。     

北大西洋沙尘与大气稳定度以及层云的关系

来自于西北非洲的沙尘粒子经常被输送到北大西洋(5 0°W～ 2 0°W,1 0°N～ 2 5°N)区域,夏季 7月份最为明显,沙尘输送带位于两逆温层之间.沙尘的辐射效应主要体现在冷却海表面而加热低对流层,因此沙尘有可能通过影响大气垂直稳定度从而影响海洋层云.试图通过分析 1 984年至 1 989年共 6年的7月份沙尘气溶胶、云观测资料来揭示沙尘气溶胶与大气稳定度以及层云之间的相互关系.结果表明,沙尘气溶胶能够通过影响大气稳定度而对层云产生影响,尽管该信号由于受到其他因素的干扰不容易提取出来     

Weather phenomena of the Colorado rockies

From field observations in the mountain region of Colorado, it was determined that the major portion of the state's moisture is brought in by the winter cyclones. Winter winds redistribute the snow, and Chinook winds remove a portion of it from the mountain region and adjacent plains.Summer storms of three types tend to redistribute the moisture derived from melting snow. Two types, of almost daily summer occurrence, the regional and local or valley storms, are topographically-confined convection phenomena, which daily transfer small amounts of moisture across divides. Cyclones tend to augment the violence of both other types; anticyclones inhibit the regional storms, but have a negligible effect on the local storms.Numerous barometric, electrical, and optical phenomena of great interest but minor climatic importance are briefly described. Hypotheses explaining the various major and minor phenomena are presented, and possible applications of the results of this and further studies of mountain weather conditions are suggested.