DOI: 10.1002/2017JA024904
Scopus记录号: 2-s2.0-85045751647
论文题名: Dipolarization Fronts With Associated Energized Electrons in Saturn's Magnetotail
作者: Smith A.W. ; Jackman C.M. ; Thomsen M.F. ; Sergis N. ; Mitchell D.G. ; Roussos E.
刊名: Journal of Geophysical Research: Space Physics
ISSN: 21699380
出版年: 2018
卷: 123, 期: 4 起始页码: 2714
结束页码: 2735
语种: 英语
英文关键词: Cassini
; dipolarization
; magnetotail
; reconnection
; Saturn
英文摘要: We present a statistical study of dipolarization fronts within Saturn's magnetotail. Automated methods were used to identify 28 significant southward rotations of the field coupled with enhancements in the electron energy. The observed dipolarizations cover the majority of the magnetotail, though possess a strong dawn-dusk asymmetry (79% occur postmidnight). Almost half (43%) of dipolarizations occur within 3 hr of another event, though these chains are solely observed postmidnight. Most pitch angle distributions of the heated electron populations show increased relative fluxes parallel or perpendicular to the field, likely due to nonlocal heating effects. The electron temperature and density following the passage of a front are anticorrelated; the temperature increases are accompanied by a decrease in their density. The temperature increases by factors of 4–12, while the density drops by factors of 3–10. Premidnight events consistently show the smallest relative heating and density depletion, suggesting they are observed closer to their generation. In contrast, the location of the postmidnight x-line is inferred to be more variable, with a large variety of heating factors observed. Forty percent of the events show a strong reduction in water (W+) group fraction, likely related to either the preferential loss of equatorial heavy ions in departing plasmoids or the closure of open field. Two of these events show significant compositional changes suggesting the addition of plasma of external origin; we suggest that these events involved the closure of open field. ©2018. The Authors. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/114111
Appears in Collections: 气候减缓与适应
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作者单位: Department of Physics and Astronomy, University of Southampton, Southampton, United Kingdom; Planetary Science Institute, Tucson, AZ, United States; Office of Space Research and Technology, Academy of Athens, Athens, Greece; Institute of Astronomy, Astrophysics, Space Applications and Remote Sensing, National Observatory of Athens, Athens, Greece; Applied Physics Laboratory, The Johns Hopkins University, Laurel, MD, United States; Max-Planck-Institut für Sonnensystemforschung, Goettingen, Germany
Recommended Citation:
Smith A.W.,Jackman C.M.,Thomsen M.F.,et al. Dipolarization Fronts With Associated Energized Electrons in Saturn's Magnetotail[J]. Journal of Geophysical Research: Space Physics,2018-01-01,123(4)