| AN EFFECT OF PERPENDICULAR DIFFUSION ON THE ANISOTROPY OF SOLAR ENERGETIC PARTICLES FROM UNCONNECTED SOURCES | |
Qin, G. ; He, H. -Q.; Zhang, M.; Qin, G (reprint author), Chinese Acad Sci, State Key Lab Space Weather, Ctr Space Sci & Appl Res, Beijing 100190, Peoples R China.
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| Department | 空间科学部 |
| Source Publication | ASTROPHYSICAL JOURNAL
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| 2011 | |
| Volume | 738Issue:1Pages:28 |
| ISSN | 0004-637X |
| Language | 英语 |
| Keyword | Diffusion Interplanetary Medium Sun: Flares Sun: Particle Emission |
| Abstract | 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.; 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. |
| Indexed By | SCI |
| Funding Project | 中国科学院空间科学与应用研究中心 |
| Document Type | 期刊论文 |
| Identifier | http://ir.nssc.ac.cn/handle/122/3191 |
| Collection | 空间科学部 |
| Corresponding Author | Qin, G (reprint author), Chinese Acad Sci, State Key Lab Space Weather, Ctr Space Sci & Appl Res, Beijing 100190, Peoples R China. |
| Recommended Citation GB/T 7714 | Qin, G.,He, H. -Q.,Zhang, M.,et al. 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.,&Qin, G .(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. |
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