Imperial College London

DrMarinaGaland

Faculty of Natural SciencesDepartment of Physics

Reader in Planetary Science
 
 
 
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m.galand Website

 
 
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Huxley BuildingSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
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97 results found

Mendillo M, Narvaez C, Vogt MF, Mayyasi M, Forbes J, Galand M, Thiemann E, Benna M, Eparvier F, Chamberlin P, Mahaffy P, Andersson Let al., Sources of Ionospheric Variability at Mars, Journal of Geophysical Research: Space Physics, ISSN: 2169-9380

JOURNAL ARTICLE

Eriksson AI, Engelhardt IAD, André M, Boström R, Edberg NJT, Johansson FL, Odelstad E, Vigren E, Wahlund JE, Henri P, Lebreton JP, Miloch WJ, Paulsson JJP, Simon Wedlund C, Yang L, Karlsson T, Jarvinen R, Broiles T, Mandt K, Carr CM, Galand M, Nilsson H, Norberg Cet al., 2017, Cold and warm electrons at comet 67P/Churyumov-Gerasimenko, Astronomy and Astrophysics, Vol: 605, ISSN: 0004-6361

© ESO, 2017. 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

JOURNAL ARTICLE

Hajra R, Henri P, Vallières X, Galand M, Héritier K, Eriksson AI, Odelstad E, Edberg NJT, Burch JL, Broiles T, Goldstein R, Glassmeier KH, Richter I, Goetz C, Tsurutani BT, Nilsson H, Altwegg K, Rubin Met al., 2017, Impact of a cometary outburst on its ionosphere. Rosetta Plasma Consortium observations of the outburst exhibited by comet 67P/Churyumov-Gerasimenko on 19 February 2016, Astronomy & Astrophysics, ISSN: 0004-6361

JOURNAL ARTICLE

Heritier KL, Henri P, Vallières X, Galand M, Odelstad E, Eriksson AI, Johansson FL, Altwegg K, Behar E, Beth A, Broiles TW, Burch JL, Carr CM, Cupido E, Nilsson H, Rubin M, Vigren Eet al., 2017, Vertical structure of the near-surface expanding ionosphere of comet 67P probed by Rosetta, Monthly Notices of the Royal Astronomical Society, Vol: 469, Pages: S118-S129, ISSN: 0035-8711

JOURNAL ARTICLE

Moore L, Galand MIF, Kliore AJ, Nagy AF, O'Donoghue Jet al., 2017, Saturn's Ionosphere, Saturn in the 21st Century, Editors: Baines, Publisher: Cambridge University Press

This chapter summarizes our current understanding of the ionosphere of Saturn. We give an overview of Saturn ionospheric science from the Voyager era to the present, with a focus on the wealth of new data and discoveries enabled by Cassini, including a massive increase in the number of electron density altitude profiles. We discuss recent ground-based detection of the effect of "ring rain" on Saturn's ionosphere, and present possible model interpretations of the observations. Finally, we outline current model-data discrepancies and indicate how future observations can help in advancing our understanding of the various controlling physical and chemical processes.

BOOK CHAPTER

Vigren E, Altwegg K, Edberg NJT, Eriksson AI, Galand M, Henri P, Johansson F, Odelstad E, Tzou C-Y, Vallieres Xet al., 2017, MODEL-OBSERVATION COMPARISONS OF ELECTRON NUMBER DENSITIES IN THE COMA OF 67P/CHURYUMOV-GERASIMENKO DURING 2015 JANUARY (vol 152, 59, 2016), ASTRONOMICAL JOURNAL, Vol: 153, ISSN: 0004-6256

JOURNAL ARTICLE

Vigren E, Altwegg K, Edberg NJT, Eriksson AI, Galand M, Henri P, Johansson F, Odelstad E, Tzou C-Y, Valliéres Xet al., 2017, ERRATUM: “MODEL–OBSERVATION COMPARISONS OF ELECTRON NUMBER DENSITIES IN THE COMA OF 67P/CHURYUMOV-GERASIMENKO DURING 2015 JANUARY” (2016, AJ, 152, 59), The Astronomical Journal, Vol: 153, Pages: 50-50

JOURNAL ARTICLE

Vigren E, André M, Edberg NJT, Engelhardt IAD, Eriksson AI, Galand M, Goetz C, Henri P, Heritier K, Johansson FL, Nilsson H, Odelstad E, Rubin M, Stenberg-Wieser G, Tzou C-Y, Vallières Xet al., 2017, Effective ion speeds at ∼200–250 km from comet 67P/Churyumov–Gerasimenko near perihelion, Monthly Notices of the Royal Astronomical Society, Vol: 469, Pages: S142-S148, ISSN: 0035-8711

JOURNAL ARTICLE

Beth A, Altwegg K, Balsiger H, Berthelier J-J, Calmonte U, Combi MR, De Keyser J, Dhooghe F, Fiethe B, Fuselier SA, Galand M, Gasc S, Gombosi TI, Hansen KC, Hassig M, Heritier KL, Kopp E, Le Roy L, Mandt KE, Peroy S, Rubin M, Semon T, Tzou C-Y, Vigren Eet al., 2016, First in situ detection of the cometary ammonium ion NH4+ (protonated ammonia NH3) in the coma of 67P/C-G near perihelion, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 462, Pages: S562-S572, ISSN: 0035-8711

JOURNAL ARTICLE

Chadney JM, Galand M, Koskinen TT, Miller S, Sanz-Forcada J, Unruh YC, Yelle RVet al., 2016, EUV-driven ionospheres and electron transport on extrasolar giant planets orbiting active stars, ASTRONOMY & ASTROPHYSICS, Vol: 587, ISSN: 1432-0746

JOURNAL ARTICLE

Fuselier SA, Altwegg K, Balsiger H, Berthelier JJ, Beth A, Bieler A, Briois C, Broiles TW, Burch JL, Calmonte U, Cessateur G, Combi M, De Keyser J, Fiethe B, Galand M, Gasc S, Gombosi TI, Gunell H, Hansen KC, Hassig M, Heritier KL, Korth A, Le Roy L, Luspay-Kuti A, Mall U, Mandt KE, Petrinec SM, Reme H, Rinaldi M, Rubin M, Semon T, Trattner KJ, Tzou C-Y, Vigren E, Waite JH, Wurz Pet al., 2016, Ion chemistry in the coma of comet 67P near perihelion, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 462, Pages: S67-S77, ISSN: 0035-8711

JOURNAL ARTICLE

Galand M, Heritier KL, Odelstad E, Henri P, Broiles TW, Allen AJ, Altwegg K, Beth A, Burch JL, Carr CM, Cupido E, Eriksson AI, Glassmeier K-H, Johansson FL, Lebreton J-P, Mandt KE, Nilsson H, Richter I, Rubin M, Sagnieres LBM, Schwartz SJ, Semon T, Tzou C-Y, Vallieres X, Vigren E, Wurz Pet al., 2016, Ionospheric plasma of comet 67P probed by Rosetta at 3 au from the Sun, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 462, Pages: S331-S351, ISSN: 0035-8711

JOURNAL ARTICLE

Grun E, Agarwal J, Altobelli N, Altwegg K, Bentley MS, Biver N, Della Corte V, Edberg N, Feldman PD, Galand M, Geiger B, Goetz C, Grieger B, Guettler C, Henri P, Hofstadter M, Horanyi M, Jehin E, Krueger H, Lee S, Mannel T, Morales E, Mousis O, Mueller M, Opitom C, Rotundi A, Schmied R, Schmidt F, Sierks H, Snodgrass C, Soja RH, Sommer M, Srama R, Tzou C-Y, Vincent J-B, Yanamandra-Fisher P, A'Hearn MF, Erikson AI, Barbieri C, Barucci MA, Bertaux J-L, Bertini I, Burch J, Colangeli L, Cremonese G, Da Deppo V, Davidsson B, Debei S, De Cecco M, Deller J, Feaga LM, Ferrari M, Fornasier S, Fulle M, Gicquel A, Gillon M, Green SF, Groussin O, Gutierrez PJ, Hofmann M, Hviid SF, Ip W-H, Ivanovski S, Jorda L, Keller HU, Knight MM, Knollenberg J, Koschny D, Kramm J-R, Kuehrt E, Kuppers M, Lamy PL, Lara LM, Lazzarin M, Lopez-Moreno JJ, Manfroid J, Epifani EM, Marzari F, Naletto G, Oklay N, Palumbo P, Parker JW, Rickman H, Rodrigo R, Rodriguez J, Schindhelm E, Shi X, Sordini R, Steffl AJ, Stern SA, Thomas N, Tubiana C, Weaver HA, Weissman P, Zakharov VVet al., 2016, The 2016 Feb 19 outburst of comet 67P/CG: an ESA Rosetta multi-instrument study, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 462, Pages: S220-S234, ISSN: 0035-8711

JOURNAL ARTICLE

Mandt KE, Eriksson A, Edberg NJT, Koenders C, Broiles T, Fuselier SA, Henri P, Nemeth Z, Alho M, Biver N, Beth A, Burch J, Carr C, Chae K, Coates AJ, Cupido E, Galand M, Glassmeier K-H, Goetz C, Goldstein R, Hansen KC, Haiducek J, Kallio E, Lebreton J-P, Luspay-Kuti A, Mokashi P, Nilsson H, Opitz A, Richter I, Samara M, Szego K, Tzou C-Y, Volwerk M, Wedlund CS, Wieser GSet al., 2016, RPC observation of the development and evolution of plasma interaction boundaries at 67P/Churyumov-Gerasimenko, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 462, Pages: S9-S22, ISSN: 0035-8711

JOURNAL ARTICLE

Moore L, Stallard T, Galand MIF, 2016, Upper atmospheres of the giant planets, Heliophysics: Active Stars, their Astrospheres, and Impacts on Planetary Environments, Editors: Schrijver, Bagenal, Sojka, Publisher: Cambridge University Press, Pages: 175-200, ISBN: 9781107090477

BOOK CHAPTER

Raghuram S, Bhardwaj A, Galand M, 2016, PREDICTION OF FORBIDDEN ULTRAVIOLET AND VISIBLE EMISSIONS IN COMET 67P/CHURYUMOV-GERASIMENKO, ASTROPHYSICAL JOURNAL, Vol: 818, ISSN: 0004-637X

JOURNAL ARTICLE

Vigren E, Altwegg K, Edberg NJT, Eriksson AI, Galand M, Henri P, Johansson F, Odelstad E, Tzou C-Y, Vallieres Xet al., 2016, MODEL-OBSERVATION COMPARISONS OF ELECTRON NUMBER DENSITIES IN THE COMA OF 67P/CHURYUMOV-GERASIMENKO DURING 2015 JANUARY, ASTRONOMICAL JOURNAL, Vol: 152, ISSN: 0004-6256

JOURNAL ARTICLE

Vigren E, Galand M, Wellbrock A, Coates AJ, Cui J, Edberg NJT, Lavvas P, Sagnieres L, Snowden D, Vuitton V, Wahlund J-Eet al., 2016, SUPRATHERMAL ELECTRONS IN TITAN'S SUNLIT IONOSPHERE: MODEL-OBSERVATION COMPARISONS, ASTROPHYSICAL JOURNAL, Vol: 826, ISSN: 0004-637X

JOURNAL ARTICLE

Badman SV, Branduardi-Raymont G, Galand M, Hess SLG, Krupp N, Lamy L, Melin H, Tao Cet al., 2015, Auroral Processes at the Giant Planets: Energy Deposition, Emission Mechanisms, Morphology and Spectra, SPACE SCIENCE REVIEWS, Vol: 187, Pages: 99-179, ISSN: 0038-6308

JOURNAL ARTICLE

Chadney JM, Galand M, Unruh YC, Koskinen TT, Sanz-Forcada Jet al., 2015, XUV-driven mass loss from extrasolar giant planets orbiting active stars, ICARUS, Vol: 250, Pages: 357-367, ISSN: 0019-1035

JOURNAL ARTICLE

Cui J, Galand M, Yelle RV, Wei Y, Zhang S-Jet al., 2015, Day-to-night transport in the Martian ionosphere: Implications from total electron content measurements, JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, Vol: 120, Pages: 2333-2346, ISSN: 2169-9380

JOURNAL ARTICLE

Cui J, Galand M, Zhang SJ, Vigren E, Zou Het al., 2015, The electron thermal structure in the dayside Martian ionosphere implied by the MGS radio occultation data, JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS, Vol: 120, Pages: 278-286, ISSN: 2169-9097

JOURNAL ARTICLE

Fuselier SA, Altwegg K, Balsiger H, Berthelier JJ, Bieler A, Briois C, Broiles TW, Burch JL, Calmonte U, Cessateur G, Combi M, De Keyser J, Fiethe B, Galand M, Gasc S, Gombosi TI, Gune H, Hansen KC, Haessig M, Jaeckel A, Korth A, Le Roy L, Mall U, Mandt KE, Petrinec SM, Raghuram S, Reme H, Rinaldi M, Rubin M, Semon T, Trattner KJ, Tzou C-Y, Vigren E, Waite JH, Wurz Pet al., 2015, ROSINA/DFMS and IES observations of 67P: Ion-neutral chemistry in the coma of a weakly outgassing comet, ASTRONOMY & ASTROPHYSICS, Vol: 583, ISSN: 1432-0746

JOURNAL ARTICLE

Haessig M, Altwegg K, Balsiger H, Bar-Nun A, Berthelier JJ, Bieler A, Bochsler P, Briois C, Calmonte U, Combi M, De Keyser J, Eberhardt P, Fiethe B, Fuselier SA, Galand M, Gasc S, Gombosi TI, Hansen KC, Jaeckel A, Keller HU, Kopp E, Korth A, Kuehrt E, Le Roy L, Mall U, Marty B, Mousis O, Neefs E, Owen T, Reme H, Rubin M, Semon T, Tornow C, Tzou C-Y, Waite JH, Wurz Pet al., 2015, Time variability and heterogeneity in the coma of 67P/Churyumov-Gerasimenko, SCIENCE, Vol: 347, ISSN: 0036-8075

JOURNAL ARTICLE

Lavvas P, Yelle RV, Heays AN, Campbell L, Brunger MJ, Galand M, Vuitton Vet al., 2015, N-2 state population in Titan's atmosphere, ICARUS, Vol: 260, Pages: 29-59, ISSN: 0019-1035

JOURNAL ARTICLE

Sagnieres LBM, Galand M, Cui J, Lavvas PP, Vigren E, Vuitton V, Yelle RV, Wellbrock A, Coates AJet al., 2015, Influence of local ionization on ionospheric densities in Titan's upper atmosphere, JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, Vol: 120, Pages: 5899-5921, ISSN: 2169-9380

JOURNAL ARTICLE

Tinetti G, Drossart P, Eccleston P, Hartogh P, Isaak K, Linder M, Lovis C, Micela G, Ollivier M, Puig L, Ribas I, Snellen I, Swinyard B, Allard F, Barstow J, Cho J, Coustenis A, Cockell C, Correia A, Decin L, de Kok R, Deroo P, Encrenaz T, Forget F, Glasse A, Griffith C, Guillot T, Koskinen T, Lammer H, Leconte J, Maxted P, Mueller-Wodarg I, Nelson R, North C, Palle E, Pagano I, Piccioni G, Pinfield D, Selsis F, Sozzetti A, Stixrude L, Tennyson J, Turrini D, Zapatero-Osorio M, Beaulieu J-P, Grodent D, Guedel M, Luz D, Norgaard-Nielsen HU, Ray T, Rickman H, Selig A, Swain M, Banaszkiewicz M, Barlow M, Bowles N, Branduardi-Raymont G, du Foresto VC, Gerard J-C, Gizon L, Hornstrup A, Jarchow C, Kerschbaum F, Kovacs G, Lagage P-O, Lim T, Lopez-Morales M, Malaguti G, Pace E, Pascale E, Vandenbussche B, Wright G, Ramos Zapata G, Adriani A, Azzollini R, Balado A, Bryson I, Burston R, Colome J, Crook M, Di Giorgio A, Griffin M, Hoogeveen R, Ottensamer R, Irshad R, Middleton K, Morgante G, Pinsard F, Rataj M, Reess J-M, Savini G, Schrader J-R, Stamper R, Winter B, Abe L, Abreu M, Achilleos N, Ade P, Adybekian V, Affer L, Agnor C, Agundez M, Alard C, Alcala J, Allende Prieto C, Alonso Floriano FJ, Altieri F, Alvarez Iglesias CA, Amado P, Andersen A, Aylward A, Baffa C, Bakos G, Ballerini P, Banaszkiewicz M, Barber RJ, Barrado D, Barton EJ, Batista V, Bellucci G, Belmonte Aviles JA, Berry D, Bezard B, Biondi D, Blecka M, Boisse I, Bonfond B, Borde P, Boerner P, Bouy H, Brown L, Buchhave L, Budaj J, Bulgarelli A, Burleigh M, Cabral A, Capria MT, Cassan A, Cavarroc C, Cecchi-Pestellini C, Cerulli R, Chadney J, Chamberlain S, Charnoz S, Jessen NC, Ciaravella A, Claret A, Claudi R, Coates A, Cole R, Collura A, Cordier D, Covino E, Danielski C, Damasso M, Deeg HJ, Delgado-Mena E, Del Vecchio C, Demangeon O, De Sio A, De Wit J, Dobrijevic M, Doel P, Dominic C, Dorfi E, Eales S, Eiroa C, Espinoza Contreras M, Esposito M, Eymet V, Fabrizio N, Fernandez M, Femena Castella B, Figueira Pet al., 2015, The EChO science case, EXPERIMENTAL ASTRONOMY, Vol: 40, Pages: 329-391, ISSN: 0922-6435

JOURNAL ARTICLE

Vigren E, Galand M, Eriksson AI, Edberg NJT, Odelstad E, Schwartz SJet al., 2015, ON THE ELECTRON-TO-NEUTRAL NUMBER DENSITY RATIO IN THE COMA OF COMET 67P/CHURYUMOV-GERASIMENKO: GUIDING EXPRESSION AND SOURCES FOR DEVIATIONS, ASTROPHYSICAL JOURNAL, Vol: 812, ISSN: 0004-637X

JOURNAL ARTICLE

Vigren E, Galand M, Lavvas P, Eriksson AI, Wahlund J-Eet al., 2015, On the possibility of significant electron depletion due to nanograin charging in the coma of comet 67p/churyumov-gerasimenko near perihelion, Astrophysical Journal, Vol: 798, ISSN: 1538-4357

JOURNAL ARTICLE

Galand MIF, Coates A, Cravens T, Wahlund J-Eet al., 2014, Titan's Ionosphere, Titan: Interior, Surface, Atmosphere, and Space Environment, Editors: Mueller-Wodarg, Griffith, Lellouch, Cravens, Publisher: Cambridge University Press, Pages: 376-418, ISBN: 9780521199926

BOOK CHAPTER

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