| Where is the cosmic-ray modulation boundary of the heliosphere? | |
| Zhang, Ming; Luo, Xi; Pogorelov, Nikolai | |
| Department | 空间科学部 |
| Source Publication | Physics of Plasmas
 |
| 2015 | |
| Volume | 22Issue:9 |
| ISSN | 1070-664X |
| Language | 英语 |
| Abstract | The intensity of Galactic cosmic rays in the heliosphere is modulated by solar activities. The outer boundary where the solar modulation begins has always been a subject matter of debate in the cosmic-ray and heliophysics community. Various experimental methods and theoretical model calculations have been used to determine the boundary. Although the heliopause was always suspected to be the boundary, it is only until very recently after Voyager 1 had crossed the heliopause did we confirm that the boundary is indeed the heliopause. In this paper, we use a model simulation and detailed Voyager observation of cosmic rays at the heliopause crossing to show that the modulation boundary, in fact, is a fraction of an AU beyond the heliopause. Such a conclusion requires a very low turbulence level of the interstellar magnetic field in the outer heliosheath. According to the quasi-linear theory, a low level of turbulence should result in a very large diffusion coefficient parallel to the magnetic field and a very small perpendicular diffusion coefficient. For the first time, we are confident that Voyager 1 has obtained the truly pristine local interstellar cosmic-ray spectra down to the energies below 1 MeV. The cosmic-ray intensity is rapidly filtered by a thin layer of the interstellar magnetic field immediately outside of the heliopause. Its filtration amount depends on the conditions of magnetic field turbulence on the both sides of the heliopause, thus making it solar-cycle dependent as well. © 2015 AIP Publishing LLC. |
| Indexed By | SCI ; EI |
| Document Type | 期刊论文 |
| Identifier | http://ir.nssc.ac.cn/handle/122/4667 |
| Collection | 空间科学部 |
| Recommended Citation GB/T 7714 | Zhang, Ming,Luo, Xi,Pogorelov, Nikolai. Where is the cosmic-ray modulation boundary of the heliosphere?[J]. Physics of Plasmas,2015,22(9). |
| APA | Zhang, Ming,Luo, Xi,&Pogorelov, Nikolai.(2015).Where is the cosmic-ray modulation boundary of the heliosphere?.Physics of Plasmas,22(9). |
| MLA | Zhang, Ming,et al."Where is the cosmic-ray modulation boundary of the heliosphere?".Physics of Plasmas 22.9(2015). |
| Files in This Item: | ||||||
| File Name/Size | DocType | Version | Access | License | ||
| 2015229.pdf（1686KB） | 期刊论文 | 出版稿 | 开放获取 | CC BY-NC-SA | Application Full Text | |
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