| OBSERVATIONAL EVIDENCE FOR THE RELATIONSHIP BETWEEN WALEN SLOPE AND AMPLITUDE RATIO OF INWARD TO OUTWARD ALFVEN WAVES IN THE SOLAR WIND | |
| Yang, L.; Lee, L. C.; Chao, J. K.; Hsieh, W. C.; Luo, Q. Y.; Li, J. P.; Shi, J. K.; Wu, D. J.; Yang, L (reprint author), Chinese Acad Sci, Purple Mt Observ, Nanjing 210008, Peoples R China.; Yang, L (reprint author), Chinese Acad Sci, Natl Space Sci Ctr, State Key Lab Space Weather, Beijing 100190, Peoples R China.; Lee, LC (reprint author), Natl Cent Univ, Inst Space Sci, Jhongli 320, Taiwan.; Lee, LC (reprint author), Acad Sinica, Inst Earth Sci, Taipei 11529, Taiwan. | |
| Department | 空间科学部 |
| Source Publication | ASTROPHYSICAL JOURNAL
 |
| 2016 | |
| Volume | 817Issue:2Pages:178 |
| ISSN | 0004-637X |
| Language | 英语 |
| Keyword | Magnetohydrodynamics (Mhd) Methods: Analytical Plasmas Solar Wind Waves |
| Abstract | Assuming that the observed Alfven waves in the solar wind are the superposition of inward-and outward-propagating Alfven waves, we obtain an analytical relation from which the observed Walen slope R-W can give a theoretical estimate of the amplitude ratio R-vA of inward to outward waves. From the Wind data at 1 AU, we select 37 Alfven wave events classified observationally as three kinds: dominant outward Alfven waves with vertical bar R-W vertical bar >= 0.75 (Class A), dominant outward Alfven waves with vertical bar R-W vertical bar < 0.75 (Class B), and dominant inward Alfven waves with vertical bar R-W vertical bar < 0.75 (Class C). For Class A events the theoretical predictions of R-vA based on R-W deviate from the wave amplitude observations, but for Class B and C events the theoretical predictions agree well with related observations, being a direct observational evidence that the superposition of inward and outward Alfven waves can cause the subunity of R-W. A simple simulation is made with a white Gaussian noise to demonstrate that a small noise could reproduce the observed properties of all three kinds of events cause the measured parameters of waves with vertical bar R-W vertical bar >= 0.75 in Class A to deviate significantly from the true values more than waves with vertical bar R-W vertical bar < 0.75. The simulation implies that the observational results based on wave amplitudes seem. reliable only for waves with vertical bar R-W vertical bar < 0.75. The R-vA ratios calculated from the analytical relation based on R-W are closer to true values than those obtained from wave amplitude observations. |
| Indexed By | SCI |
| Document Type | 期刊论文 |
| Identifier | http://ir.nssc.ac.cn/handle/122/5294 |
| Collection | 空间科学部 |
| Corresponding Author | Yang, L (reprint author), Chinese Acad Sci, Purple Mt Observ, Nanjing 210008, Peoples R China.; Yang, L (reprint author), Chinese Acad Sci, Natl Space Sci Ctr, State Key Lab Space Weather, Beijing 100190, Peoples R China.; Lee, LC (reprint author), Natl Cent Univ, Inst Space Sci, Jhongli 320, Taiwan.; Lee, LC (reprint author), Acad Sinica, Inst Earth Sci, Taipei 11529, Taiwan. |
| Recommended Citation GB/T 7714 | Yang, L.,Lee, L. C.,Chao, J. K.,et al. OBSERVATIONAL EVIDENCE FOR THE RELATIONSHIP BETWEEN WALEN SLOPE AND AMPLITUDE RATIO OF INWARD TO OUTWARD ALFVEN WAVES IN THE SOLAR WIND[J]. ASTROPHYSICAL JOURNAL,2016,817(2):178. |
| APA | Yang, L..,Lee, L. C..,Chao, J. K..,Hsieh, W. C..,Luo, Q. Y..,...&Lee, LC .(2016).OBSERVATIONAL EVIDENCE FOR THE RELATIONSHIP BETWEEN WALEN SLOPE AND AMPLITUDE RATIO OF INWARD TO OUTWARD ALFVEN WAVES IN THE SOLAR WIND.ASTROPHYSICAL JOURNAL,817(2),178. |
| MLA | Yang, L.,et al."OBSERVATIONAL EVIDENCE FOR THE RELATIONSHIP BETWEEN WALEN SLOPE AND AMPLITUDE RATIO OF INWARD TO OUTWARD ALFVEN WAVES IN THE SOLAR WIND".ASTROPHYSICAL JOURNAL 817.2(2016):178. |
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