Flow directions of low-energy ions in and around the diamagnetic cavity of comet 67P
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
The flow direction of low-energy ions around comet 67P/Churyumov–Gerasimenko has previously been difficult to constrain due to the influence of the spacecraft potential. The Ion Composition Analyzer of the Rosetta Plasma Consortium (RPC-ICA) on Rosetta measured the distribution function of positive ions with energies down to just a few eV/q throughout the escort phase of the mission. Unfortunately, the substantial negative spacecraft potential distorted the directional information of the low-energy data. In this work, we present the flow directions of low-energy ions around comet 67P, corrected for the spacecraft potential using Particle-In-Cell simulation results. We focus on the region in and around the diamagnetic cavity, where low-energy ions are especially important for the dynamics. We separate between slightly accelerated ‘burst’ features and a more constant ‘band’ of low-energy ions visible in the data. The ‘bursts’ are flowing radially outwards from the nucleus with an antisunward component while the ‘band’ is predominantly streaming back towards the comet. This provides evidence of counter-streaming ions, which has implications for the overall expansion velocity of the ions. The backstreaming ions are present also at times when the diamagnetic cavity was not detected, indicating that the process accelerating the ions back towards the comet is not connected to the cavity boundary.
Date Issued
2021-11
Date Acceptance
2021-08-26
Citation
Monthly Notices of the Royal Astronomical Society, 2021, 507 (4), pp.4900-4913
ISSN
0035-8711
Publisher
Oxford University Press
Start Page
4900
End Page
4913
Journal / Book Title
Monthly Notices of the Royal Astronomical Society
Volume
507
Issue
4
Copyright Statement
© The Author(s) 2021. Published by Oxford University Press on behalf of Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative
Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium,
provided the original work is properly cited.
Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium,
provided the original work is properly cited.
License URL
Identifier
https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000702151300016&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Subjects
67P/CHURYUMOV-GERASIMENKO
Astronomy & Astrophysics
EVOLUTION
FIELD
MAGNETOMETER
methods: numerical-comets: individual: 67P/Churyumov-Gerasimenko
MODEL
Physical Sciences
PLASMA
plasmas - methods: data analysis
PROBE
REGION
ROSETTA
Science & Technology
TEMPERATURE
Publication Status
Published
Date Publish Online
2021-09-02