Coronal mass ejections (CMEs) and their geoeffectiveness
Coronal mass ejections (CMEs) and their geoeffectiveness
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DOI：
10.1109/27.902210
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发表时间：
2000-12
影响因子：
1.5
通讯作者：
S. Plunkett;S. Wu
中科院分区：
文献类型：
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作者：
S. Plunkett;S. Wu
太阳的活动驱动地球空间（即近地环境）的变化。观测表明，太阳的等离子体喷射，称为日冕物质喷射（CME），是地磁风暴的主要原因。大约三十年前，通过使用星载日冕仪（OSO-7、Skylab/ATM 和 P78-1）发现了日冕物质抛射的全球尺度太阳动力学特征。在了解日冕物质抛射的物理性质方面已经取得了重大进展。观测表明，这些全球规模的日冕物质抛射的大小约为太阳半径（/spl sim/6.7/spl times/10/sup 5/ km），靠近太阳，每次事件的质量约为 10/sup 15/ g，能量相当于 10/sup 32/ ergs 量级的大型耀斑。日冕物质抛射的径向传播速度范围很广，从每秒几十到几千公里。因此，到达近地环境 [即 1 AU（天文单位）] 的传输时间可以快至 40 小时到 100 小时。地理效应事件的典型传播时间为 /spl sim/60-80 小时。本文由两部分组成：1）总结从天空实验室到目前 SOHO 观测到的日冕物质抛射。将特别关注 SOHO/LASCO/EIT 观测及其导致地球有效日冕物质抛射的特征。 2）将回顾解释这一令人着迷的现象的物理本质的理论和模型的时间顺序发展。最后，将通过一个例子通过观测和模型来说明日冕物质抛射的地缘效应。
The Sun's activity drives the variability of geospace (i.e., near-Earth environment). Observations show that the ejection of plasma from the Sun, called coronal mass ejections (CMEs), are the major cause of geomagnetic storms. This global-scale solar dynamical feature of coronal mass ejection was discovered almost three decades ago by the use of space-borne coronagraphs (OSO-7, Skylab/ATM and P78-1). Significant progress has been made in understanding the physical nature of the CMEs. Observations show that these global-scale CMEs have size in the order of a solar radius (/spl sim/6.7/spl times/10/sup 5/ km) near the Sun, and each event involves a mass of about 10/sup 15/ g and an energy comparable to that of a large flare on the order of 10/sup 32/ ergs. The radial propagation speeds of CMEs have a wide range from tens to thousands of kilometers per second. Thus, the transit time to near Earth's environment [i.e., 1 AU (astronomical unit)] can be as fast as 40 hours to 100 hours. The typical transit time for geoeffective events is /spl sim/60-80 h. This paper consists of two parts: 1) A summary of the observed CMEs from Skylab to the present SOHO will be presented. Special attention will be made to SOHO/LASCO/EIT observations and their characteristics leading to a geoeffective CME. 2) The chronological development of theory and models to interpret the physical nature of this fascinating phenomenon will be reviewed. Finally, an example will be presented to illustrate the geoeffectiveness of the CMEs by using both observation and model.