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DOI | 10.1029/2019GL084163 |
Statistical Properties of Molecular Ions in the Ring Current Observed by the Arase (ERG) Satellite | |
Seki, K.1; Keika, K.1; Kasahara, S.1; Yokota, S.2; Horr, T.3; Asamura, K.4; Higashio, N.1; Takada, M.1; Ogawa, Y.5; Matsuoka, A.4; Teramoto, M.6; Miyoshi, Y.3; Shinohara, I4 | |
2019-08-16 | |
发表期刊 | GEOPHYSICAL RESEARCH LETTERS |
ISSN | 0094-8276 |
EISSN | 1944-8007 |
出版年 | 2019 |
卷号 | 46期号:15页码:8643-8651 |
文章类型 | Article |
语种 | 英语 |
国家 | Japan |
英文摘要 | Molecular ions in the magnetosphere can be a tracer of fast ion outflows from the deep ionosphere. Statistical properties of molecular ions (O-2(+)/NO+/N-2(+)) in the ring current are investigated based on ion composition measurements (<180 keV/q) by medium-energy particle experiments-electron analyzer and low-energy particle experiments-ion mass analyzer instruments on board the Arase (Exploration of energization and Radiation in Geospace, ERG) satellite. The investigated period from late March to December 2017 includes 11 geomagnetic storms with the minimum Dst index less than -40 nT. The molecular ions are observed in the region of L = 2.5-6.6 and clearly identified at energies above similar to 12 keV during most magnetic storms. During quiet times, molecular ions are not observed. The average energy density ratio of the molecular ions to O+ is similar to 3%. The ratio tends to increase with the size of magnetic storms. Existence of molecular ions even during small magnetic storms suggests that the fast ion outflow from the deep ionosphere occurs frequently during geomagnetically active periods. Plain Language Summary Molecular ions usually exist only in the low-altitude (< 300 km) deep ionosphere and cannot escape to space without a fast ion outflow to overcome a rapid loss due to dissociative recombination. Thus, molecular ion escape from the terrestrial atmosphere to space can be used as a tracer of effective ion loss from the deep ionosphere. Here we report new observations by Arase satellite that enables definitive identification of molecular ions by frequent time-of-flight mode observations. The statistical analysis shows that molecular ions exist in near-Earth space during most magnetic storms, while they are not detected during geomagnetically quiet periods. The existence of molecular ions even during small magnetic storms suggests that the magnetic storm is an effective driver of the ion loss from the deep terrestrial ionosphere. |
领域 | 气候变化 |
收录类别 | SCI-E |
WOS记录号 | WOS:000483812500007 |
WOS关键词 | OUTFLOW ; ENERGIZATION ; NO+ |
WOS类目 | Geosciences, Multidisciplinary |
WOS研究方向 | Geology |
引用统计 | |
文献类型 | 期刊论文 |
条目标识符 | http://119.78.100.173/C666/handle/2XK7JSWQ/186013 |
专题 | 气候变化 |
作者单位 | 1.Univ Toxyo, Grad Sch Sci, Dept Earth & Planetary Sci, Tokyo, Japan; 2.Osaka Univ, Grad Sch Sci, Osaka, Japan; 3.Nagoya Univ, Inst Space Earth Environm Res, Nagoya, Aichi, Japan; 4.JAXA, Inst Space & Astronaut Sci, Tokyo, Japan; 5.Natl Inst Polar Res, Tachikawa, Tokyo, Japan; 6.Kyushu Inst Technol, Grad Sch Engn, Kitakyushu, Fukuoka, Japan |
推荐引用方式 GB/T 7714 | Seki, K.,Keika, K.,Kasahara, S.,et al. Statistical Properties of Molecular Ions in the Ring Current Observed by the Arase (ERG) Satellite[J]. GEOPHYSICAL RESEARCH LETTERS,2019,46(15):8643-8651. |
APA | Seki, K..,Keika, K..,Kasahara, S..,Yokota, S..,Horr, T..,...&Shinohara, I.(2019).Statistical Properties of Molecular Ions in the Ring Current Observed by the Arase (ERG) Satellite.GEOPHYSICAL RESEARCH LETTERS,46(15),8643-8651. |
MLA | Seki, K.,et al."Statistical Properties of Molecular Ions in the Ring Current Observed by the Arase (ERG) Satellite".GEOPHYSICAL RESEARCH LETTERS 46.15(2019):8643-8651. |
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