Energy conversion in cometary atmospheres Hybrid modeling of 67P/Churyumov-Gerasimenko

J. Lindkvist; M. Hamrin; H. Gunell; H. Nilsson; C. S. Wedlund; E. Kallio; I. Mann; T. Pitkanen; T. Karlsson

doi:10.1051/0004-6361/201732353

Energy conversion in cometary atmospheres Hybrid modeling of 67P/Churyumov-Gerasimenko

J. Lindkvist^*
, M. Hamrin
, H. Gunell
, H. Nilsson
, C. S. Wedlund
, E. Kallio
, I. Mann
, T. Pitkanen
, T. Karlsson

^*Tämän työn vastaava kirjoittaja

Tutkimustuotos: Lehtiartikkeli › Article › Scientific › vertaisarvioitu

18 Sitaatiot (Scopus)

172 Lataukset (Pure)

Abstrakti

Aims. We wish to investigate the energy conversion between particles and electromagnetic fields and determine the location where it occurs in the plasma environment of comets.

Methods. We used a hybrid plasma model that included photoionization, and we considered two cases of the solar extreme ultraviolet flux. Other parameters corresponded to the conditions of comet 67P/Churyumov-Gerasimenko at a heliocentric distance of 1.5 AU.

Results. We find that a shock-like structure is formed upstream of the comet and acts as an electromagnetic generator, similar to the bow shock at Earth that slows down the solar wind. The Poynting flux transports electromagnetic energy toward the inner coma, where newly born cometary ions are accelerated. Upstream of the shock-like structure, we find local energy transfer from solar wind ions to cometary ions. We show that mass loading can be a local process with a direct transfer of energy, but also part of a dynamo system with electromagnetic generators and loads.

Conclusions. The energization of cometary ions is governed by a dynamo system for weak ionization, but changes into a large conversion region with local transfer of energy directly from solar wind protons for high ionization.

Alkuperäiskieli	Englanti
Artikkeli	A81
Sivumäärä	10
Julkaisu	Astronomy & Astrophysics
Vuosikerta	616
DOI - pysyväislinkit	https://doi.org/10.1051/0004-6361/201732353 https://doi.org/10.1051/0004-6361/201732353
Tila	Julkaistu - 21 elok. 2018
OKM-julkaisutyyppi	A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Rahoitus

The software used in this work was in part developed by the DOE NNSA-ASC OASCR Flash Center at the University of Chicago. The hybrid solver is part of the openly available FLASH code and can be downloaded from http://flash.uchicago.edu/. The simulation results are available from the corresponding author upon request. This research was conducted using resources provided by the Swedish National Infrastructure for Computing (SNIC) at the High Performance Computing Center North (HPC2N), Umea University, Sweden. J.L. and M.H. are funded by the Swedish National Space Board (SNSB project 201/15). H.G. was supported by the Belgian Science Policy Office through the Solar-Terrestrial Centre of Excellence, and by PRODEX/ROSETTA/ROSINA PEA 4000107705. H.N. was supported by the Swedish National Space Board under contract 112/13 and by the Swedish Research Council under contract 2015-04187. C.S.W. is supported by the Research Council of Norway grant No. 240000. I.M. was supported by the Research Council of Norway grant No. 262941.

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@article{90575c15217943ddbad5684b3b45fdd5,

title = "Energy conversion in cometary atmospheres Hybrid modeling of 67P/Churyumov-Gerasimenko",

abstract = "Aims. We wish to investigate the energy conversion between particles and electromagnetic fields and determine the location where it occurs in the plasma environment of comets.Methods. We used a hybrid plasma model that included photoionization, and we considered two cases of the solar extreme ultraviolet flux. Other parameters corresponded to the conditions of comet 67P/Churyumov-Gerasimenko at a heliocentric distance of 1.5 AU.Results. We find that a shock-like structure is formed upstream of the comet and acts as an electromagnetic generator, similar to the bow shock at Earth that slows down the solar wind. The Poynting flux transports electromagnetic energy toward the inner coma, where newly born cometary ions are accelerated. Upstream of the shock-like structure, we find local energy transfer from solar wind ions to cometary ions. We show that mass loading can be a local process with a direct transfer of energy, but also part of a dynamo system with electromagnetic generators and loads.Conclusions. The energization of cometary ions is governed by a dynamo system for weak ionization, but changes into a large conversion region with local transfer of energy directly from solar wind protons for high ionization.",

keywords = "comets: individual: 67P/Churyumov-Gerasimenko, Sun: UV radiation, solar wind, methods: numerical, plasmas, acceleration of particles, SOLAR-WIND, BOW SHOCK, PLASMA ENVIRONMENT, SIMULATION CODE, MAGNETIC-FIELD, IONS",

author = "J. Lindkvist and M. Hamrin and H. Gunell and H. Nilsson and Wedlund, \{C. S.\} and E. Kallio and I. Mann and T. Pitkanen and T. Karlsson",

note = "Publisher Copyright: {\textcopyright} ESO 2018.",

year = "2018",

month = aug,

day = "21",

doi = "10.1051/0004-6361/201732353",

language = "English",

volume = "616",

journal = "Astronomy \& Astrophysics",

issn = "1432-0746",

publisher = "EDP Sciences",

}

TY - JOUR

T1 - Energy conversion in cometary atmospheres Hybrid modeling of 67P/Churyumov-Gerasimenko

AU - Lindkvist, J.

AU - Hamrin, M.

AU - Gunell, H.

AU - Nilsson, H.

AU - Wedlund, C. S.

AU - Kallio, E.

AU - Mann, I.

AU - Pitkanen, T.

AU - Karlsson, T.

N1 - Publisher Copyright: © ESO 2018.

PY - 2018/8/21

Y1 - 2018/8/21

N2 - Aims. We wish to investigate the energy conversion between particles and electromagnetic fields and determine the location where it occurs in the plasma environment of comets.Methods. We used a hybrid plasma model that included photoionization, and we considered two cases of the solar extreme ultraviolet flux. Other parameters corresponded to the conditions of comet 67P/Churyumov-Gerasimenko at a heliocentric distance of 1.5 AU.Results. We find that a shock-like structure is formed upstream of the comet and acts as an electromagnetic generator, similar to the bow shock at Earth that slows down the solar wind. The Poynting flux transports electromagnetic energy toward the inner coma, where newly born cometary ions are accelerated. Upstream of the shock-like structure, we find local energy transfer from solar wind ions to cometary ions. We show that mass loading can be a local process with a direct transfer of energy, but also part of a dynamo system with electromagnetic generators and loads.Conclusions. The energization of cometary ions is governed by a dynamo system for weak ionization, but changes into a large conversion region with local transfer of energy directly from solar wind protons for high ionization.

AB - Aims. We wish to investigate the energy conversion between particles and electromagnetic fields and determine the location where it occurs in the plasma environment of comets.Methods. We used a hybrid plasma model that included photoionization, and we considered two cases of the solar extreme ultraviolet flux. Other parameters corresponded to the conditions of comet 67P/Churyumov-Gerasimenko at a heliocentric distance of 1.5 AU.Results. We find that a shock-like structure is formed upstream of the comet and acts as an electromagnetic generator, similar to the bow shock at Earth that slows down the solar wind. The Poynting flux transports electromagnetic energy toward the inner coma, where newly born cometary ions are accelerated. Upstream of the shock-like structure, we find local energy transfer from solar wind ions to cometary ions. We show that mass loading can be a local process with a direct transfer of energy, but also part of a dynamo system with electromagnetic generators and loads.Conclusions. The energization of cometary ions is governed by a dynamo system for weak ionization, but changes into a large conversion region with local transfer of energy directly from solar wind protons for high ionization.

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

KW - Sun: UV radiation

KW - solar wind

KW - methods: numerical

KW - plasmas

KW - acceleration of particles

KW - SOLAR-WIND

KW - BOW SHOCK

KW - PLASMA ENVIRONMENT

KW - SIMULATION CODE

KW - MAGNETIC-FIELD

KW - IONS

UR - https://www.scopus.com/pages/publications/85056551495

U2 - 10.1051/0004-6361/201732353

DO - 10.1051/0004-6361/201732353

M3 - Article

SN - 1432-0746

VL - 616

JO - Astronomy & Astrophysics

JF - Astronomy & Astrophysics

M1 - A81

ER -

Energy conversion in cometary atmospheres Hybrid modeling of 67P/Churyumov-Gerasimenko

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