地球极区电离层对行星际激波的响应

	地球极区电离层对行星际激波的响应
	郭孝城 ; 胡友秋
刊名	地球物理学报
	2007
卷号	50 期号:4 页码:951-956
关键词	地球磁层电离层行星际激波场向电流数值模拟
ISSN号	0001-5733
其他题名	Response of Earth s ionosphere to interplanetary shocks
通讯作者	北京8701信箱
中文摘要	本文就地球电离层对行星际激波的动力学响应进行三维全球数值模拟研究.背景行星际磁场为螺旋场,南北分量为零;初始电离层由Ⅰ区场向电流和相应的晨昏电场所主导;行星际激波沿日地连线方向撞击地球.模拟结果表明,在激波的作用下,电离层Ⅰ区电流系统向子夜方向运动,在向阳侧相继出现与原Ⅰ区电流反向的异常场向电流对和同向的新生Ⅰ区电流对.该异常场向电流对在极盖区形成瞬间昏晨电场,尾随原Ⅰ区电流向夜侧方向漂移直至湮没.与此同时,新生的Ⅰ区电流不断增强并向夜侧和赤道方向延伸,最终取代原Ⅰ区电流,相应极盖区又恢复到原来的晨昏电场状态.这一响应过程和行星际激波强度有关:激波强度越强,新生的Ⅰ区场向电流也越强,它向赤道方向延伸的距离也越大,能到达的纬度也越低.上述结果在趋势上与观测到的输运对流涡旋和亚极光块的运动特征一致.
英文摘要	This paper presents three-dimensional，golbal numerical simulations of the dynamic response of the Earth’s ionosphere to interplanetary shocks. The background interplanetary magnetic field is spiral with a vanishing south-north component，the initial ionosphere is dominated by the region I field aligned current (FAC) and the corresponding dawn-dusk electric field，and the interplanetary shock collides with the Earth along the Sun-Earth line.It is shown that under the action of the shock，the region I current moves towards the midnight，accompanied by a successive occurrence of two FAC structures:an anomalous FAC pair of opposite direction to the region I current and a new region I current of the same direction. The anomalous FAC pair creates a transient dusl-dawn electric field over the polar cap，tailing behind the oniginal region I current and drifting towards the night side until it falls into oblivion. In the meantime，the new region I current keeps increasing and expanding towards the night and equator side，and it eventually replaces the oniginal region I current，so the polar cap returns to a state as on乡nal with a dawn-dusk electric field. Such a response depends on the strength of the interplanetary shock:for a stronger shock，the new region I current gets stronger，extends for a longer observations distance towards the equator，and reaches a lower latitude. These results tend to agree with the associated with traveling convection }rtices and midday sub-auroral patches.
学科主题	空间物理
资助信息	国家自然科学基金
语种	中文
内容类型	期刊论文
源URL	[http://ir.cssar.ac.cn/handle/122/1196]
专题	国家空间科学中心_空间科学部
推荐引用方式 GB/T 7714	郭孝城,胡友秋. 地球极区电离层对行星际激波的响应[J]. 地球物理学报,2007,50(4):951-956.
APA	郭孝城,&胡友秋.(2007).地球极区电离层对行星际激波的响应.地球物理学报,50(4),951-956.
MLA	郭孝城,et al."地球极区电离层对行星际激波的响应".地球物理学报 50.4(2007):951-956.