Brightening of onset arc precedes the dipolarization onset: THEMIS observations of two events on 1 March 2008
文献类型：期刊论文
| 作者 | Kan, J. R.; Li, H.; Wang, C.; Frey, H. U.; Kubyshkina, M. V.; Runov, A.; Xiao, C. J.; Lyu, L. H.; Sun, W. |
| 刊名 | ANNALES GEOPHYSICAE
 |
| 出版日期 | 2011 |
| 卷号 | 29期号:11页码:2045-2059 |
| ISSN号 | 0992-7689 |
| 关键词 | Magnetospheric physics Magnetosphere-ionosphere interactions |
| 通讯作者 | Li, H (reprint author), Chinese Acad Sci, Natl Space Sci Ctr, Beijing, Peoples R China. |
| 中文摘要 | We present a new M-I coupling model of substorm during southward IMF based on the THEMIS observations of two events on 1 March 2008. The first event (E-1) was classified as a pseudo-breakup: brightening of the onset arc preceded the first dipolarization onset by similar to 71 +/- 3 s, but the breakup arcs faded within similar to 5 min without substantial poleward expansion and the dipolarization stopped and reversed to thinning. The second event (E-2) was identified as a substorm: brightening of the second onset arc preceded the second dipolarization onset by similar to 80 +/- 3 s, leading to a full-scale expanding auroral bulge during the substorm expansion phase for similar to 20 min. The Alfven travel time from the ionosphere to the dipolarization onset region is estimated at similar to 69.3 s in E-1; at similar to 80.3 s in E-2, which matched well with the observed time delay of the dipolarization onset after the brightening of the onset arc, respectively in E-1 and E-2. Brightening of the onset arc precedes the dipolarization onset suggest that the onset arc brightening is caused by the intense upward field-aligned currents originating from the divergence of the Cowling electrojet in the ionosphere. The Cowling electrojet current loop (CECL) is formed to close the field-aligned currents at all times. The closure current in the Alfven wavefront is anti-parallel to the cross-tail current. Dipolarization onset occurs when the Alfven wavefront incident on the near-Earth plasma sheet to disrupt the cross-tail current in the dipolarization region. Slow MHD waves dominate the disruption of the cross-tail current in the dipolarization region. |
| 英文摘要 | We present a new M-I coupling model of substorm during southward IMF based on the THEMIS observations of two events on 1 March 2008. The first event (E-1) was classified as a pseudo-breakup: brightening of the onset arc preceded the first dipolarization onset by similar to 71 +/- 3 s, but the breakup arcs faded within similar to 5 min without substantial poleward expansion and the dipolarization stopped and reversed to thinning. The second event (E-2) was identified as a substorm: brightening of the second onset arc preceded the second dipolarization onset by similar to 80 +/- 3 s, leading to a full-scale expanding auroral bulge during the substorm expansion phase for similar to 20 min. The Alfven travel time from the ionosphere to the dipolarization onset region is estimated at similar to 69.3 s in E-1; at similar to 80.3 s in E-2, which matched well with the observed time delay of the dipolarization onset after the brightening of the onset arc, respectively in E-1 and E-2. Brightening of the onset arc precedes the dipolarization onset suggest that the onset arc brightening is caused by the intense upward field-aligned currents originating from the divergence of the Cowling electrojet in the ionosphere. The Cowling electrojet current loop (CECL) is formed to close the field-aligned currents at all times. The closure current in the Alfven wavefront is anti-parallel to the cross-tail current. Dipolarization onset occurs when the Alfven wavefront incident on the near-Earth plasma sheet to disrupt the cross-tail current in the dipolarization region. Slow MHD waves dominate the disruption of the cross-tail current in the dipolarization region. |
| 学科主题 | 空间物理 |
| 资助信息 | National Natural Science Foundation of China [40831060]; Specialized Research Fund for State Key Laboratories in China; ONR [N00014-08-1-0439]; Canadian Space Agency |
| 收录类别 | SCI ; EI |
| 语种 | 英语 |
| 公开日期 | 2014-12-15 |
| 源URL | [http://ir.nssc.ac.cn/handle/122/3242]  |
| 专题 | 国家空间科学中心_空间科学部 |
| 推荐引用方式 GB/T 7714 | Kan, J. R.,Li, H.,Wang, C.,et al. Brightening of onset arc precedes the dipolarization onset: THEMIS observations of two events on 1 March 2008[J]. ANNALES GEOPHYSICAE,2011,29(11):2045-2059. |
| APA | Kan, J. R..,Li, H..,Wang, C..,Frey, H. U..,Kubyshkina, M. V..,...&Sun, W..(2011).Brightening of onset arc precedes the dipolarization onset: THEMIS observations of two events on 1 March 2008.ANNALES GEOPHYSICAE,29(11),2045-2059. |
| MLA | Kan, J. R.,et al."Brightening of onset arc precedes the dipolarization onset: THEMIS observations of two events on 1 March 2008".ANNALES GEOPHYSICAE 29.11(2011):2045-2059. |
入库方式： OAI收割
来源：国家空间科学中心
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