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LIBRIS Formathandbok  (Information om MARC21)
FältnamnIndikatorerMetadata
00007267naa a2200697 4500
001oai:DiVA.org:kth-217060
003SwePub
008171123s2017 | |||||||||||000 ||eng|
009oai:DiVA.org:uu-337755
0247 a https://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-2170602 URI
0247 a https://doi.org/10.1051/0004-6361/2016301592 DOI
0247 a https://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3377552 URI
040 a (SwePub)kthd (SwePub)uu
041 a engb eng
042 9 SwePub
072 7a ref2 swepub-contenttype
072 7a art2 swepub-publicationtype
1001 a Eriksson, Anders I.u Uppsala universitet,Institutet för rymdfysik, Uppsalaavdelningen4 aut0 (Swepub:uu)andeerik
2451 0a Cold and warm electrons at comet 67P/Churyumov-Gerasimenko
264 c 2017-05-24
264 1b EDP SCIENCES S A,c 2017
338 a print2 rdacarrier
500 a QC 20171123
500 a Funding: The results presented here are only possible thanks to the combined efforts over 20 yr by many groups and individuals involved in Rosetta, including but not restricted to the ESA project teams at ESTEC, ESOC and ESAC and all people involved in designing, building, testing and operating RPC and LAP. We thank Kathrin Altwegg for discussions of the pulses in LAP and COPS. Rosetta is a European Space Agency (ESA) mission with contributions from its member states and the National Aeronautics and Space Administration (NASA). The work on RPC-LAP data was funded by the Swedish National Space Board under contracts 109/12, 171/12, 135/13, 166/14 and 168/15, and by Vetenskapsradet under contract 621-2013-4191. This work has made use of the AMDA and RPC Quicklook database, provided by a collaboration between the Centre de Donnees de la Physique des Plasmas CDPP (supported by CNRS, CNES, Observatoire de Paris and Universite Paul Sabatier, Toulouse), and Imperial College London (supported by the UK Science and Technology Facilities Council).
520 a Context. Strong electron cooling on the neutral gas in cometary comae has been predicted for a long time, but actual measurements of low electron temperature are scarce. Aims. Our aim is to demonstrate the existence of cold electrons in the inner coma of comet 67P/Churyumov-Gerasimenko and show filamentation of this plasma. Methods. In situ measurements of plasma density, electron temperature and spacecraft potential were carried out by the Rosetta Langmuir probe instrument, LAP. We also performed analytical modelling of the expanding two-temperature electron gas. Results. LAP data acquired within a few hundred km from the nucleus are dominated by a warm component with electron temperature typically 5-10 eV at all heliocentric distances covered (1.25 to 3.83 AU). A cold component, with temperature no higher than about 0.1 eV, appears in the data as short (few to few tens of seconds) pulses of high probe current, indicating local enhancement of plasma density as well as a decrease in electron temperature. These pulses first appeared around 3 AU and were seen for longer periods close to perihelion. The general pattern of pulse appearance follows that of neutral gas and plasma density. We have not identified any periods with only cold electrons present. The electron flux to Rosetta was always dominated by higher energies, driving the spacecraft potential to order -10 V. Conclusions. The warm (5-10 eV) electron population observed throughout the mission is interpreted as electrons retaining the energy they obtained when released in the ionisation process. The sometimes observed cold populations with electron temperatures below 0.1 eV verify collisional cooling in the coma. The cold electrons were only observed together with the warm population. The general appearance of the cold population appears to be consistent with a Haser-like model, implicitly supporting also the coupling of ions to the neutral gas. The expanding cold plasma is unstable, forming filaments that we observe as pulses.
650 7a NATURVETENSKAPx Fysikx Fusion, plasma och rymdfysik0 (SwePub)103032 hsv//swe
650 7a NATURAL SCIENCESx Physical Sciencesx Fusion, Plasma and Space Physics0 (SwePub)103032 hsv//eng
650 7a NATURVETENSKAPx Fysikx Astronomi, astrofysik och kosmologi0 (SwePub)103052 hsv//swe
650 7a NATURAL SCIENCESx Physical Sciencesx Astronomy, Astrophysics and Cosmology0 (SwePub)103052 hsv//eng
653 a comets: general
653 a plasmas
653 a space vehicles: instruments
7001 a Engelhardt, Ilka. A. D.u Uppsala universitet,Institutet för rymdfysik, Uppsalaavdelningen,Institutionen för fysik och astronomi4 aut0 (Swepub:uu)ilken598
7001 a André, Matsu Uppsala universitet,Institutet för rymdfysik, Uppsalaavdelningen4 aut0 (Swepub:uu)maand125
7001 a Boström, Rolfu Uppsala universitet,Institutet för rymdfysik, Uppsalaavdelningen4 aut0 (Swepub:uu)rolfbost
7001 a Edberg, Niklas J. T.u Uppsala universitet,Institutet för rymdfysik, Uppsalaavdelningen4 aut0 (Swepub:uu)niked861
7001 a Johansson, Fredrik L.u Uppsala universitet,Institutet för rymdfysik, Uppsalaavdelningen,Institutionen för fysik och astronomi4 aut0 (Swepub:uu)frejo741
7001 a Odelstad, Eliasu Uppsala universitet,KTH,Rymd- och plasmafysik,Institutionen för fysik och astronomi,Institutet för rymdfysik, Uppsalaavdelningen4 aut0 (Swepub:uu)eliod143
7001 a Vigren, Eriku Uppsala universitet,Institutet för rymdfysik, Uppsalaavdelningen4 aut0 (Swepub:uu)erivi300
7001 a Wahlund, Jan-Eriku Uppsala universitet,Institutet för rymdfysik, Uppsalaavdelningen4 aut0 (Swepub:uu)janewahl
7001 a Henri, P.u LPC2E, Lab Phys & Chim Environm & Espace4 aut
7001 a Lebreton, J. -Pu LPC2E, Lab Phys & Chim Environm & Espace4 aut
7001 a Miloch, W. J.u Univ Oslo, Dept Phys4 aut
7001 a Paulsson, J. J. P.u Univ Oslo, Dept Phys4 aut
7001 a Wedlund, C. Simonu Univ Oslo, Dept Phys4 aut
7001 a Yang, L.u Univ Oslo, Dept Phys4 aut
7001 a Karlsson, Tomas,d 1964-u KTH,Alfvénlaboratoriet,Rymd- och plasmafysik,Royal Inst Technol, Alfvén Lab4 aut0 (Swepub:kth)u154ti5p
7001 a Jarvinen, R.u Finnish Meteorol Inst, Helsinki 005604 aut
7001 a Broiles, T.u Southwest Res Inst, San Antonio4 aut
7001 a Mandt, K.u Southwest Res Inst, San Antonio; Univ Texas San Antonio, Dept Phys & Astron4 aut
7001 a Carr, C. M.u Imperial Coll London, Dept Phys4 aut
7001 a Galand, M.u Imperial Coll London, Dept Phys4 aut
7001 a Nilsson, H.u Swedish Inst Space Phys, S-98128 Kiruna4 aut
7001 a Norberg, C.u Swedish Inst Space Phys, S-98128 Kiruna4 aut
7102 a Uppsala universitetb Institutet för rymdfysik, Uppsalaavdelningen4 org
7730 t Astronomy and Astrophysicsd : EDP SCIENCES S Ag 605q 605x 0004-6361x 1432-0746
8564 u https://doi.org/10.1051/0004-6361/201630159y Fulltext
8564 u https://www.aanda.org/articles/aa/pdf/2017/09/aa30159-16.pdf
8564 8u https://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-217060
8564 8u https://doi.org/10.1051/0004-6361/201630159
8564 8u https://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-337755

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