Average cometary ion flow pattern in the vicinity of comet 67P from moment data

Hans Nilsson, Hayley Williamson, Sofia Bergman, Gabriella Stenberg Wieser*, Martin Wieser, Etienne Behar, Anders I. Eriksson, Fredrik L. Johansson, Ingo Richter, Charlotte Goetz

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)
24 Downloads (Pure)

Abstract

Average flow patterns of ions around comet 67P detected by the RPC-ICA instrument onboard Rosetta are presented both as a time series and as a spatial distribution of the average flow in the plane perpendicular to the comet – Sun direction (Y–Z plane in the coordinate systems used). Cometary ions in the energy range up to 60 eV flow radially away from the nucleus in the Y–Z plane, irrespective of the direction of the magnetic field, throughout the mission. These ions may however be strongly affected by the spacecraft potential, the uncertainty due to this is briefly discussed. Inside the solar wind ion cavity and in the periods just before and after, the cometary pick up ions moving antisunward are deflected against the inferred solar wind electric field direction. This is opposite to what is observed for lower levels of mass-loading. These pick up ions are behaving in a similar way to the solar wind ions and are deflected due to mass-loading. A spatial asymmetry can be seen in the observations of deflected pick up ions, with motion against the electric field primarily within a radius of 200 km of the nucleus and also in the negative electric field hemisphere. Cometary ions observed by RPC-ICA typically move in the antisunward direction throughout the mission. These are average patterns, full-resolution data show very much variability.
Original languageEnglish
Pages (from-to)5263-5272
Number of pages10
JournalMonthly Notices of the Royal Astronomical Society
Volume498
Issue number4
DOIs
Publication statusPublished - 1 Nov 2020
Externally publishedYes

Keywords

  • plasmas
  • methods: data analysis
  • comets: individual: 67P

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