DOI: 10.1002/2017JA024917
Scopus记录号: 2-s2.0-85050290381
论文题名: The Dusty Plasma Disk Around the Janus/Epimetheus Ring
作者: Morooka M.W. ; Wahlund J.-E. ; Andrews D.J. ; Persoon A.M. ; Ye S.-Y. ; Kurth W.S. ; Gurnett D.A. ; Farrell W.M.
刊名: Journal of Geophysical Research: Space Physics
ISSN: 21699380
出版年: 2018
卷: 123, 期: 6 起始页码: 4668
结束页码: 4678
语种: 英语
英文关键词: dusty plasma
; planetary ring
英文摘要: We report on the electron, ion, and dust number densities and the electron temperatures obtained by the Radio and Plasma Wave Science instruments onboard Cassini during the Ring-Grazing orbits. The numerous ring passage observations show a consistent picture as follows: (1) Beyond 0.1 RS above and below the equator the electron and ion densities are quasi-neutral with a distribution similar to the one obtained in the plasma disk. (2) A sharp ion density enhancement occurs at |Z| < 0.1 RS, to more than 200 cm−3 at the equator, while the electron density remains low only to values of 50 cm−3. The electron/ion density ratio is ≦0.1 at the equator. (3) Micrometer-sized dust has also been observed at the equator. However, the region of intense dust signals is significantly narrower (|Z| < 0.02 RS) than the enhanced ion density regions. (4) The electron temperature (Te) generally decreases with decreasing Z with small Te enhancements near the equator. We show that the dust size characteristics are different depending on the distance from the equator, and the large micrometer-sized grains are more perceptible in a narrow region near the equator where the power law slope of the dust size distribution becomes less steep. As a result, different scale heights are obtained for nanometer and micrometer grains. Throughout the ring, the dominant part of the negative charges is carried by the small nanometer-sized grains. The electron/ion density ratio is variable from orbit to orbit, suggesting changes in the dust charging over time scales of weeks. ©2018. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/113747
Appears in Collections: 气候减缓与适应
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作者单位: Swedish Institute of Space Physics, Uppsala, Sweden; Department of Physics and Astronomy, University of Iowa, Iowa City, IA, United States; NASA GSFC, Greenbelt, MD, United States
Recommended Citation:
Morooka M.W.,Wahlund J.-E.,Andrews D.J.,et al. The Dusty Plasma Disk Around the Janus/Epimetheus Ring[J]. Journal of Geophysical Research: Space Physics,2018-01-01,123(6)