South - North Hemispheric Asymmetry of the FAE Distribution Around the Cusp Region: Cluster Observation

doi:10.1029/2019JA026582

	South - North Hemispheric Asymmetry of the FAE Distribution Around the Cusp Region: Cluster Observation
	Shi, Jiankui; Zhang, Ziying; Torkar, Klaus; Cheng, Zhengwei; Escoubet, Phillipe; Farzakeley, Andrew; Dunlop, Malcolm; Carr, Chris
刊名	JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
	2019
卷号	124 期号:7 页码:5342-5352
关键词	FAE events cusp region north-south asymmetry Cluster observation
DOI	10.1029/2019JA026582
英文摘要	Cluster data from late July to early October were used to study the distribution of field-aligned electron (FAE) events around the two cusps. An FAE event was defined as electron parallel flux >3 x 10(8) (cm(2) s)(-1). The total number of FAE events around the two cusps was basically identical, but downward FAE events prevailed in the south and upward FAE events in the north. In the southern cusp, the peak of the FAE events distribution versus altitude was about 1.3 R-E higher and the peak of the FAE events distribution versus invariant latitude (ILAT) was about 4 degrees ILAT lower. Only the downward FAEs around the southern cusp had a second ILAT peak, which was located about 11 degrees higher than the main peak. The normalized number of FAEs showed nearly the same features as the unnormalized number of the FAEs events. These results indicated a north-south asymmetry of the FAE distribution around the two cusps. Some causes for the asymmetry are discussed, the main ones being the asymmetry of the magnetospheric configuration resulting from geomagnetic dipolar tilt and solar wind flows, the interplanetary magnetic field asymmetry related to the magnetosphere, and the difference of ionospheric conductivity in the two hemispheres. Various solar wind-magnetosphere interaction processes, such as quasi-viscous interaction and reconnection, are responsible for the asymmetry, too. The second distribution peak (at higher ILAT) of the downward FAE events around the southern cusp corresponded to high solar wind speed and may be associated with the northward interplanetary magnetic field B-z field-aligned current at low altitude. This requires further studies, however.
语种	英语
内容类型	期刊论文
源URL	[http://ir.nssc.ac.cn/handle/122/7086]
专题	国家空间科学中心_空间科学部
推荐引用方式 GB/T 7714	Shi, Jiankui,Zhang, Ziying,Torkar, Klaus,et al. South - North Hemispheric Asymmetry of the FAE Distribution Around the Cusp Region: Cluster Observation[J]. JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS,2019,124(7):5342-5352.
APA	Shi, Jiankui.,Zhang, Ziying.,Torkar, Klaus.,Cheng, Zhengwei.,Escoubet, Phillipe.,...&Carr, Chris.(2019).South - North Hemispheric Asymmetry of the FAE Distribution Around the Cusp Region: Cluster Observation.JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS,124(7),5342-5352.
MLA	Shi, Jiankui,et al."South - North Hemispheric Asymmetry of the FAE Distribution Around the Cusp Region: Cluster Observation".JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 124.7(2019):5342-5352.