Hybrid modeling of cometary plasma environments: II. Remote-sensing of a cometary bow shock

Markku Alho; Cyril Simon Wedlund; Hans Nilsson; Esa Kallio; Riku Järvinen; Tuija Pulkkinen

doi:10.1051/0004-6361/201834863

Hybrid modeling of cometary plasma environments: II. Remote-sensing of a cometary bow shock

Markku Alho
, Cyril Simon Wedlund
, Hans Nilsson
, Esa Kallio
, Riku Järvinen
, Tuija Pulkkinen

University of Michigan, Ann Arbor
University of Oslo
Swedish Institute of Space Physics
Luleå University of Technology
Finnish Meteorological Institute

Research output: Contribution to journal › Article › Scientific › peer-review

18 Citations (Scopus)

207 Downloads (Pure)

Abstract

Context. The ESA Rosetta probe has not seen direct evidence of a fully formed bow shock at comet 67P/Churyumov-Gerasimenko (67P). Ion spectrometer measurements of cometary pickup ions measured in the vicinity of the nucleus of 67P are available and may contain signatures of the large-scale plasma environment. Aims. The aim is to investigate the possibility of using pickup ion signatures to infer the existence or nonexistence of a bow shock-like structure and possibly other large-scale plasma environment features. Methods. A numerical plasma model in the hybrid plasma description was used to model the plasma environment of a comet. Simulated pickup ion spectra were generated for different interplanetary magnetic field conditions. The results were interpreted through test particle tracing in the hybrid simulation solutions. Results. Features of the observed pickup ion energy spectrum were reproduced, and the model was used to interpret the observation to be consistent with a shock-like structure. We identify (1) a spectral break related to the bow shock, (2) a mechanism for generating the spectral break, and (3) a dependency of the energy of the spectral break on the interplanetary magnetic field magnitude and bow shock standoff distance.

Original language	English
Article number	A45
Number of pages	16
Journal	Astronomy & Astrophysics
Volume	630
Early online date	27 Feb 2019
DOIs	https://doi.org/10.1051/0004-6361/201834863
Publication status	Published - 1 Oct 2019
MoE publication type	A1 Journal article-refereed

Funding

M.A. acknowledges financial support from the Aino and Kaarlo Tiisala Foundation and the RPC meetings for fruitful discussions. C.S.W. was funded at University of Oslo by the Norwegian Research Council ?Rosetta? grant no. 240000. The authors acknowledge ISSI (Bern) and the ISSI International Team ?Plasma Environment of comet 67P after Rosetta? for fruitful discussions and collaborations. Aalto Science-IT is recognized for providing computational capacities. The Lawrence Livermore National Laboratories visualization software VisIt was used for the analysis of the simulations and the production of some publication figures. The authors would also like to thank R. Munroe (xkcd) for inspiring us in the use of sophisticated curve-smoothing technique

Keywords

Comets: general
Comets: individual: 67P/Churyumov-Gerasimenko
Methods: numerical
Plasmas
Shock waves
Techniques: miscellaneous

Access to Document

10.1051/0004-6361/201834863

ELEC_alho_Hybrid_modeling_AAFinal published version, 10.2 MB

Cite this

@article{81f189a2995d4e16b67e89a962a5ab9b,

title = "Hybrid modeling of cometary plasma environments: II. Remote-sensing of a cometary bow shock",

abstract = "Context. The ESA Rosetta probe has not seen direct evidence of a fully formed bow shock at comet 67P/Churyumov-Gerasimenko (67P). Ion spectrometer measurements of cometary pickup ions measured in the vicinity of the nucleus of 67P are available and may contain signatures of the large-scale plasma environment. Aims. The aim is to investigate the possibility of using pickup ion signatures to infer the existence or nonexistence of a bow shock-like structure and possibly other large-scale plasma environment features. Methods. A numerical plasma model in the hybrid plasma description was used to model the plasma environment of a comet. Simulated pickup ion spectra were generated for different interplanetary magnetic field conditions. The results were interpreted through test particle tracing in the hybrid simulation solutions. Results. Features of the observed pickup ion energy spectrum were reproduced, and the model was used to interpret the observation to be consistent with a shock-like structure. We identify (1) a spectral break related to the bow shock, (2) a mechanism for generating the spectral break, and (3) a dependency of the energy of the spectral break on the interplanetary magnetic field magnitude and bow shock standoff distance. ",

keywords = "Comets: general, Comets: individual: 67P/Churyumov-Gerasimenko, Methods: numerical, Plasmas, Shock waves, Techniques: miscellaneous",

author = "Markku Alho and \{Simon Wedlund\}, Cyril and Hans Nilsson and Esa Kallio and Riku J{\"a}rvinen and Tuija Pulkkinen",

note = "Funding Information: M.A. acknowledges financial support from the Aino and Kaarlo Tiisala Foundation and the RPC meetings for fruitful discussions. C.S.W. was funded at University of Oslo by the Norwegian Research Council ?Rosetta? grant no. 240000. The authors acknowledge ISSI (Bern) and the ISSI International Team ?Plasma Environment of comet 67P after Rosetta? for fruitful discussions and collaborations. Aalto Science-IT is recognized for providing computational capacities. The Lawrence Livermore National Laboratories visualization software VisIt was used for the analysis of the simulations and the production of some publication figures. The authors would also like to thank R. Munroe (xkcd) for inspiring us in the use of sophisticated curve-smoothing technique Publisher Copyright: {\textcopyright} ESO 2019.",

year = "2019",

month = oct,

day = "1",

doi = "10.1051/0004-6361/201834863",

language = "English",

volume = "630",

journal = "Astronomy \& Astrophysics",

issn = "0004-6361",

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T1 - Hybrid modeling of cometary plasma environments

T2 - II. Remote-sensing of a cometary bow shock

AU - Alho, Markku

AU - Simon Wedlund, Cyril

AU - Nilsson, Hans

AU - Kallio, Esa

AU - Järvinen, Riku

AU - Pulkkinen, Tuija

N1 - Funding Information: M.A. acknowledges financial support from the Aino and Kaarlo Tiisala Foundation and the RPC meetings for fruitful discussions. C.S.W. was funded at University of Oslo by the Norwegian Research Council ?Rosetta? grant no. 240000. The authors acknowledge ISSI (Bern) and the ISSI International Team ?Plasma Environment of comet 67P after Rosetta? for fruitful discussions and collaborations. Aalto Science-IT is recognized for providing computational capacities. The Lawrence Livermore National Laboratories visualization software VisIt was used for the analysis of the simulations and the production of some publication figures. The authors would also like to thank R. Munroe (xkcd) for inspiring us in the use of sophisticated curve-smoothing technique Publisher Copyright: © ESO 2019.

PY - 2019/10/1

Y1 - 2019/10/1

N2 - Context. The ESA Rosetta probe has not seen direct evidence of a fully formed bow shock at comet 67P/Churyumov-Gerasimenko (67P). Ion spectrometer measurements of cometary pickup ions measured in the vicinity of the nucleus of 67P are available and may contain signatures of the large-scale plasma environment. Aims. The aim is to investigate the possibility of using pickup ion signatures to infer the existence or nonexistence of a bow shock-like structure and possibly other large-scale plasma environment features. Methods. A numerical plasma model in the hybrid plasma description was used to model the plasma environment of a comet. Simulated pickup ion spectra were generated for different interplanetary magnetic field conditions. The results were interpreted through test particle tracing in the hybrid simulation solutions. Results. Features of the observed pickup ion energy spectrum were reproduced, and the model was used to interpret the observation to be consistent with a shock-like structure. We identify (1) a spectral break related to the bow shock, (2) a mechanism for generating the spectral break, and (3) a dependency of the energy of the spectral break on the interplanetary magnetic field magnitude and bow shock standoff distance.

AB - Context. The ESA Rosetta probe has not seen direct evidence of a fully formed bow shock at comet 67P/Churyumov-Gerasimenko (67P). Ion spectrometer measurements of cometary pickup ions measured in the vicinity of the nucleus of 67P are available and may contain signatures of the large-scale plasma environment. Aims. The aim is to investigate the possibility of using pickup ion signatures to infer the existence or nonexistence of a bow shock-like structure and possibly other large-scale plasma environment features. Methods. A numerical plasma model in the hybrid plasma description was used to model the plasma environment of a comet. Simulated pickup ion spectra were generated for different interplanetary magnetic field conditions. The results were interpreted through test particle tracing in the hybrid simulation solutions. Results. Features of the observed pickup ion energy spectrum were reproduced, and the model was used to interpret the observation to be consistent with a shock-like structure. We identify (1) a spectral break related to the bow shock, (2) a mechanism for generating the spectral break, and (3) a dependency of the energy of the spectral break on the interplanetary magnetic field magnitude and bow shock standoff distance.

KW - Comets: general

KW - Comets: individual: 67P/Churyumov-Gerasimenko

KW - Methods: numerical

KW - Plasmas

KW - Shock waves

KW - Techniques: miscellaneous

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U2 - 10.1051/0004-6361/201834863

DO - 10.1051/0004-6361/201834863

M3 - Article

AN - SCOPUS:85097198795

SN - 0004-6361

VL - 630

JO - Astronomy & Astrophysics

JF - Astronomy & Astrophysics

M1 - A45

ER -

Hybrid modeling of cometary plasma environments: II. Remote-sensing of a cometary bow shock

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Hybrid modeling of cometary plasma environments: II. Remote-sensing of a cometary bow shock

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