AN EFFECT OF PERPENDICULAR DIFFUSION ON THE ANISOTROPY OF SOLAR ENERGETIC PARTICLES FROM UNCONNECTED SOURCES

	AN EFFECT OF PERPENDICULAR DIFFUSION ON THE ANISOTROPY OF SOLAR ENERGETIC PARTICLES FROM UNCONNECTED SOURCES
	Qin, G.; He, H. -Q.; Zhang, M.
刊名	ASTROPHYSICAL JOURNAL
	2011
卷号	738 期号:1 页码:28
关键词	diffusion interplanetary medium Sun: flares Sun: particle emission
ISSN号	0004-637X
通讯作者	Qin, G (reprint author), Chinese Acad Sci, State Key Lab Space Weather, Ctr Space Sci & Appl Res, Beijing 100190, Peoples R China.
中文摘要	Recently, Tan and coworkers studied the 2001 September 24 solar energetic particle (SEP) event observed by the Wind spacecraft at 1 AU and found that there is a counter-streaming particle beam with a deep depression of flux at 90 degrees pitch angle during the beginning of the event. They suggested that it is a result of a reflecting boundary at some distance outside of 1 AU. While this scenario could be true under some specific configuration of an interplanetary magnetic field, in this paper we offer another possible explanation. We simulated the SEP event by solving the five-dimensional focused transport equation numerically for 40 keV electrons with perpendicular diffusion. We find that a counter-streaming particle beam with deep depression at 90 degrees pitch angle can form on Parker magnetic field lines that do not directly connect to the main particle source on the Sun in the beginning of an SEP event. It can happen when a significant number of observed particles come from adjacent field lines through parallel transport to large radial distance first, hopping across field lines through perpendicular diffusion, and then getting scattered back to 1 AU, where they combine with the particles directly coming from the Sun to form a counter-streaming beam.
英文摘要	Recently, Tan and coworkers studied the 2001 September 24 solar energetic particle (SEP) event observed by the Wind spacecraft at 1 AU and found that there is a counter-streaming particle beam with a deep depression of flux at 90 degrees pitch angle during the beginning of the event. They suggested that it is a result of a reflecting boundary at some distance outside of 1 AU. While this scenario could be true under some specific configuration of an interplanetary magnetic field, in this paper we offer another possible explanation. We simulated the SEP event by solving the five-dimensional focused transport equation numerically for 40 keV electrons with perpendicular diffusion. We find that a counter-streaming particle beam with deep depression at 90 degrees pitch angle can form on Parker magnetic field lines that do not directly connect to the main particle source on the Sun in the beginning of an SEP event. It can happen when a significant number of observed particles come from adjacent field lines through parallel transport to large radial distance first, hopping across field lines through perpendicular diffusion, and then getting scattered back to 1 AU, where they combine with the particles directly coming from the Sun to form a counter-streaming beam.
学科主题	空间物理
收录类别	SCI
资助信息	CMA [GYHY201106011]; National High-tech R&D Program of China (863 Program) [2010AA122200]; NASA [NNX08AP91G, NNX09AG29G, NNX09AB24G]; [NNSFC 41074125]; [NNSFC 40921063]
语种	英语
公开日期	2014-12-15
内容类型	期刊论文
源URL	[http://ir.nssc.ac.cn/handle/122/3191]
专题	国家空间科学中心_空间科学部
推荐引用方式 GB/T 7714	Qin, G.,He, H. -Q.,Zhang, M.. AN EFFECT OF PERPENDICULAR DIFFUSION ON THE ANISOTROPY OF SOLAR ENERGETIC PARTICLES FROM UNCONNECTED SOURCES[J]. ASTROPHYSICAL JOURNAL,2011,738(1):28.
APA	Qin, G.,He, H. -Q.,&Zhang, M..(2011).AN EFFECT OF PERPENDICULAR DIFFUSION ON THE ANISOTROPY OF SOLAR ENERGETIC PARTICLES FROM UNCONNECTED SOURCES.ASTROPHYSICAL JOURNAL,738(1),28.
MLA	Qin, G.,et al."AN EFFECT OF PERPENDICULAR DIFFUSION ON THE ANISOTROPY OF SOLAR ENERGETIC PARTICLES FROM UNCONNECTED SOURCES".ASTROPHYSICAL JOURNAL 738.1(2011):28.