DOI: 10.1029/2018JA025542
Scopus记录号: 2-s2.0-85050821184
论文题名: Ion Velocity and Electron Temperature Inside and Around the Diamagnetic Cavity of Comet 67P
作者: Odelstad E. ; Eriksson A.I. ; Johansson F.L. ; Vigren E. ; Henri P. ; Gilet N. ; Heritier K.L. ; Vallières X. ; Rubin M. ; André M.
刊名: Journal of Geophysical Research: Space Physics
ISSN: 21699380
出版年: 2018
卷: 123, 期: 7 起始页码: 5870
结束页码: 5893
语种: 英语
英文关键词: comets
; diamagnetic cavity
; electron temperature
; ion velocity
; plasma
; Rosetta
英文摘要: A major point of interest in cometary plasma physics has been the diamagnetic cavity, an unmagnetized region in the innermost part of the coma. Here we combine Langmuir and Mutual Impedance Probe measurements to investigate ion velocities and electron temperatures in the diamagnetic cavity of comet 67P, probed by the Rosetta spacecraft. We find ion velocities generally in the range 2–4 km/s, significantly above the expected neutral velocity (Formula presented.) 1 km/s, showing that the ions are (partially) decoupled from the neutrals, indicating that ion-neutral drag was not responsible for balancing the outside magnetic pressure. Observations of clear wake effects on one of the Langmuir probes showed that the ion flow was close to radial and supersonic, at least with respect to the perpendicular temperature, inside the cavity and possibly in the surrounding region as well. We observed spacecraft potentials (Formula presented.) V throughout the cavity, showing that a population of warm (∼5 eV) electrons was present throughout the parts of the cavity reached by Rosetta. Also, a population of cold ((Formula presented.)) electrons was consistently observed throughout the cavity, but less consistently in the surrounding region, suggesting that while Rosetta never entered a region of collisionally coupled electrons, such a region was possibly not far away during the cavity crossings. ©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/113627
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, Uppsala University, Uppsala, Sweden; LPC2E, CNRS, Orléans, France; Department of Physics, Imperial College London, London, United Kingdom; Physikalisches Institut, Universität Bern, Bern, Switzerland
Recommended Citation:
Odelstad E.,Eriksson A.I.,Johansson F.L.,et al. Ion Velocity and Electron Temperature Inside and Around the Diamagnetic Cavity of Comet 67P[J]. Journal of Geophysical Research: Space Physics,2018-01-01,123(7)