Global S&T Development Trend Analysis Platform of Resources and Environment
DOI | 10.1029/2019GL082008 |
Drift-Dispersed Flux Dropouts of Energetic Electrons Observed in Earth's Middle Magnetosphere by the Magnetospheric Multiscale (MMS) Mission | |
Cohen, Ian J.1; Mauk, Barry H.1; Turner, Drew L.2; Fennell, Joseph F.2; Blake, J. Bernard2; Reeves, Geoffrey D.3; Leonard, Trevor W.4; Baker, Daniel N.4; Jaynes, Allison N.5; Spence, Harlan E.6; Gabrielse, Christine2,7 | |
2019-03-28 | |
发表期刊 | GEOPHYSICAL RESEARCH LETTERS |
ISSN | 0094-8276 |
EISSN | 1944-8007 |
出版年 | 2019 |
卷号 | 46期号:6页码:3069-3078 |
文章类型 | Article |
语种 | 英语 |
国家 | USA |
英文摘要 | Energetic particle injections are characterized by dispersive or dispersionless increases in observed particle flux. Observations from National Aeronautics and Space Administration's Magnetospheric Multiscale (MMS) mission have revealed transient events displaying injection-like dispersed reductions in energetic (similar to 30-600 keV) electron flux in the dawnside magnetosphere. Although initially believed to be the result of magnetopause losses, drift tracing of the electrons suggests a source for these drift-dispersed flux dropouts in the near-to-postmidnight magnetotail suggesting that they are likely related to similar signatures previously observed at geosynchronous orbit. We suggest that the dozen examples presented are signatures of "flux-reduced injections" resulting from earthward injection in the presence of a negative phase space density radial gradient as supported by observed phase space density versus L-shell profiles. These events also display varying pitch angle responses inconsistent with a singular loss mechanism, leading to the suggestion that they result from preconditioning of the magnetotail source region prior to the injection. Plain Language Summary Energetic particles are suddenly and abruptly pushed earthward through near-Earth space via processes called "injections." These are commonly seen by spacecraft as sudden time- and energy-dependent increases in the number of observed particles and are known to play an important role in sourcing the planet's radiation belts. Investigating the processes governing energetic particle transport is critical to better understand fundamental plasma processes, the dynamics of Earth's radiation belts, and the effects of space weather. This paper investigates a set of similar, but unique, signatures where the number of particles suddenly decreases instead of increasing. The analysis presented here surprisingly reveals that the particles observed in these signatures come from the magnetotail, which raises new questions about what generates these signatures. We investigate two hypotheses to explain the observed decrease in particles: (1) that a process removes the particles from the system and (2) that a process similar to "normal" injections moves a population of decreased particles into an area where there are more particles (hence generating a local decrease). The analysis finds that the secondary hypothesis is far more likely to be the primary driver while the first cannot be ruled out entirely as a secondary contributor. |
英文关键词 | MMS injections magnetosphere |
领域 | 气候变化 |
收录类别 | SCI-E |
WOS记录号 | WOS:000464650400007 |
WOS关键词 | RADIATION-BELT ; PARTICLE INJECTIONS ; MULTISATELLITE MEASUREMENTS ; RELATIVISTIC ELECTRONS ; ACCELERATION ; SUBSTORM ; SIMULATION ; PLASMA ; INNER ; ENERGIZATION |
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/181754 |
专题 | 气候变化 |
作者单位 | 1.Johns Hopkins Univ, Appl Phys Lab, Johns Hopkins Rd, Laurel, MD 20723 USA; 2.Aerosp Corp, El Segundo, CA 90245 USA; 3.Los Alamos Natl Lab, Los Alamos, NM USA; 4.Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO 80309 USA; 5.Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA; 6.Univ New Hampshire, Space Sci Ctr, Durham, NH 03824 USA; 7.Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90024 USA |
推荐引用方式 GB/T 7714 | Cohen, Ian J.,Mauk, Barry H.,Turner, Drew L.,et al. Drift-Dispersed Flux Dropouts of Energetic Electrons Observed in Earth's Middle Magnetosphere by the Magnetospheric Multiscale (MMS) Mission[J]. GEOPHYSICAL RESEARCH LETTERS,2019,46(6):3069-3078. |
APA | Cohen, Ian J..,Mauk, Barry H..,Turner, Drew L..,Fennell, Joseph F..,Blake, J. Bernard.,...&Gabrielse, Christine.(2019).Drift-Dispersed Flux Dropouts of Energetic Electrons Observed in Earth's Middle Magnetosphere by the Magnetospheric Multiscale (MMS) Mission.GEOPHYSICAL RESEARCH LETTERS,46(6),3069-3078. |
MLA | Cohen, Ian J.,et al."Drift-Dispersed Flux Dropouts of Energetic Electrons Observed in Earth's Middle Magnetosphere by the Magnetospheric Multiscale (MMS) Mission".GEOPHYSICAL RESEARCH LETTERS 46.6(2019):3069-3078. |
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