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Meredith CJ, Alexeev II, Badman SV, Belenkaya ES, Cowley SWH, Dougherty MK, Kalegaev VV, Lewis GR, Nichols JD. Saturn's dayside ultraviolet auroras: Evidence for morphological dependence on the direction of the upstream interplanetary magnetic field. JOURNAL OF GEOPHYSICAL RESEARCH. SPACE PHYSICS 2014; 119:1994-2008. [PMID: 26167441 PMCID: PMC4497471 DOI: 10.1002/2013ja019598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 02/25/2014] [Accepted: 03/12/2014] [Indexed: 06/04/2023]
Abstract
UNLABELLED We examine a unique data set from seven Hubble Space Telescope (HST) "visits" that imaged Saturn's northern dayside ultraviolet emissions exhibiting usual circumpolar "auroral oval" morphologies, during which Cassini measured the interplanetary magnetic field (IMF) upstream of Saturn's bow shock over intervals of several hours. The auroras generally consist of a dawn arc extending toward noon centered near ∼15° colatitude, together with intermittent patchy forms at ∼10° colatitude and poleward thereof, located between noon and dusk. The dawn arc is a persistent feature, but exhibits variations in position, width, and intensity, which have no clear relationship with the concurrent IMF. However, the patchy postnoon auroras are found to relate to the (suitably lagged and averaged) IMF Bz , being present during all four visits with positive Bz and absent during all three visits with negative Bz . The most continuous such forms occur in the case of strongest positive Bz . These results suggest that the postnoon forms are associated with reconnection and open flux production at Saturn's magnetopause, related to the similarly interpreted bifurcated auroral arc structures previously observed in this local time sector in Cassini Ultraviolet Imaging Spectrograph data, whose details remain unresolved in these HST images. One of the intervals with negative IMF Bz however exhibits a prenoon patch of very high latitude emission extending poleward of the dawn arc to the magnetic/spin pole, suggestive of the occurrence of lobe reconnection. Overall, these data provide evidence of significant IMF dependence in the morphology of Saturn's dayside auroras. KEY POINTS We examine seven cases of joint HST Saturn auroral images and Cassini IMF dataThe persistent but variable dawn arc shows no obvious IMF dependencePatchy postnoon auroras are present for northward IMF but not for southward IMF.
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Affiliation(s)
- C J Meredith
- Department of Physics and Astronomy, University of Leicester Leicester, UK
| | - I I Alexeev
- Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics Moscow, Russian Federation
| | - S V Badman
- Department of Physics and Astronomy, University of Leicester Leicester, UK ; Department of Physics, University of Lancaster Lancaster, UK
| | - E S Belenkaya
- Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics Moscow, Russian Federation
| | - S W H Cowley
- Department of Physics and Astronomy, University of Leicester Leicester, UK
| | - M K Dougherty
- Blackett Laboratory, Imperial College London London, UK
| | - V V Kalegaev
- Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics Moscow, Russian Federation
| | - G R Lewis
- Mullard Space Science Laboratory, University College London Dorking, UK
| | - J D Nichols
- Department of Physics and Astronomy, University of Leicester Leicester, UK
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Badman SV, Achilleos N, Arridge CS, Baines KH, Brown RH, Bunce EJ, Coates AJ, Cowley SWH, Dougherty MK, Fujimoto M, Hospodarsky G, Kasahara S, Kimura T, Melin H, Mitchell DG, Stallard T, Tao C. Cassini observations of ion and electron beams at Saturn and their relationship to infrared auroral arcs. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011ja017222] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Radioti A, Grodent D, Gérard JC, Milan SE, Bonfond B, Gustin J, Pryor W. Bifurcations of the main auroral ring at Saturn: ionospheric signatures of consecutive reconnection events at the magnetopause. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011ja016661] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- A. Radioti
- Laboratoire de Physique Atmosphérique et Planétaire, Institut d'Astrophysique et de Géophysique; Université de Liège; Liège Belgium
| | - D. Grodent
- Laboratoire de Physique Atmosphérique et Planétaire, Institut d'Astrophysique et de Géophysique; Université de Liège; Liège Belgium
| | - J.-C. Gérard
- Laboratoire de Physique Atmosphérique et Planétaire, Institut d'Astrophysique et de Géophysique; Université de Liège; Liège Belgium
| | - S. E. Milan
- Department of Physics and Astronomy; University of Leicester; Leicester U. K
| | - B. Bonfond
- Laboratoire de Physique Atmosphérique et Planétaire, Institut d'Astrophysique et de Géophysique; Université de Liège; Liège Belgium
| | - J. Gustin
- Laboratoire de Physique Atmosphérique et Planétaire, Institut d'Astrophysique et de Géophysique; Université de Liège; Liège Belgium
| | - W. Pryor
- Science Department; Central Arizona College; Coolidge Arizona USA
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Grodent D, Gustin J, Gérard JC, Radioti A, Bonfond B, Pryor WR. Small-scale structures in Saturn's ultraviolet aurora. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011ja016818] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- D. Grodent
- Laboratoire de Physique Atmosphérique et Planétaire; Université de Liège; Liège Belgium
| | - J. Gustin
- Laboratoire de Physique Atmosphérique et Planétaire; Université de Liège; Liège Belgium
| | - J.-C. Gérard
- Laboratoire de Physique Atmosphérique et Planétaire; Université de Liège; Liège Belgium
| | - A. Radioti
- Laboratoire de Physique Atmosphérique et Planétaire; Université de Liège; Liège Belgium
| | - B. Bonfond
- Laboratoire de Physique Atmosphérique et Planétaire; Université de Liège; Liège Belgium
| | - W. R. Pryor
- Science Department; Central Arizona College; Coolidge Arizona USA
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Galand M, Moore L, Mueller-Wodarg I, Mendillo M, Miller S. Response of Saturn's auroral ionosphere to electron precipitation: Electron density, electron temperature, and electrical conductivity. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010ja016412] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Marina Galand
- Space and Atmospheric Physics Group, Department of Physics; Imperial College London; London UK
- Center for Space Physics; Boston University; Boston Massachusetts USA
| | - Luke Moore
- Center for Space Physics; Boston University; Boston Massachusetts USA
| | - Ingo Mueller-Wodarg
- Space and Atmospheric Physics Group, Department of Physics; Imperial College London; London UK
- Center for Space Physics; Boston University; Boston Massachusetts USA
| | - Michael Mendillo
- Center for Space Physics; Boston University; Boston Massachusetts USA
| | - Steve Miller
- Atmospheric Physics Laboratory, Department of Physics and Astronomy; University College London; London UK
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Carbary JF, Mitchell DG, Paranicas C, Roelof EC, Krimigis SM, Krupp N, Khurana K, Dougherty M. Pitch angle distributions of energetic electrons at Saturn. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010ja015987] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- J. F. Carbary
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
| | - D. G. Mitchell
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
| | - C. Paranicas
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
| | - E. C. Roelof
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
| | - S. M. Krimigis
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
| | - N. Krupp
- Max Planck Institut für Sonnensystemforschung; Katlenburg-Lindau Germany
| | - K. Khurana
- Institute of Geophysics and Planetary Physics; University of California; Los Angeles California USA
| | - M. Dougherty
- Space and Atmospheric Physics Group; Imperial College; London UK
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Lamy L, Cecconi B, Prangé R, Zarka P, Nichols JD, Clarke JT. An auroral oval at the footprint of Saturn's kilometric radio sources, colocated with the UV aurorae. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2009ja014401] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- L. Lamy
- LESIA, Observatoire de Paris, UPMC, CNRS; Université Paris Diderot; Meudon France
- Space and Atmospheric Physics Group, Blackett Laboratory; Imperial College London; London UK
| | - B. Cecconi
- LESIA, Observatoire de Paris, UPMC, CNRS; Université Paris Diderot; Meudon France
| | - R. Prangé
- LESIA, Observatoire de Paris, UPMC, CNRS; Université Paris Diderot; Meudon France
| | - P. Zarka
- LESIA, Observatoire de Paris, UPMC, CNRS; Université Paris Diderot; Meudon France
| | - J. D. Nichols
- Department of Physics and Astronomy; University of Leicester; Leicester UK
| | - J. T. Clarke
- Center for Space Physics; Boston University; Boston Massachusetts USA
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Clarke JT, Nichols J, Gérard JC, Grodent D, Hansen KC, Kurth W, Gladstone GR, Duval J, Wannawichian S, Bunce E, Cowley SWH, Crary F, Dougherty M, Lamy L, Mitchell D, Pryor W, Retherford K, Stallard T, Zieger B, Zarka P, Cecconi B. Response of Jupiter's and Saturn's auroral activity to the solar wind. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008ja013694] [Citation(s) in RCA: 141] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- J. T. Clarke
- Center for Space Physics; Boston University; Boston Massachusetts USA
| | - J. Nichols
- Center for Space Physics; Boston University; Boston Massachusetts USA
| | | | - D. Grodent
- LPAP; Université de Liège; Liege Belgium
| | - K. C. Hansen
- AOSS Department; University of Michigan; Ann Arbor Michigan USA
| | - W. Kurth
- Department of Physics and Astronomy; University of Iowa; Iowa City Iowa USA
| | | | - J. Duval
- Center for Space Physics; Boston University; Boston Massachusetts USA
| | - S. Wannawichian
- Center for Space Physics; Boston University; Boston Massachusetts USA
| | - E. Bunce
- Department of Physics and Astronomy; University of Leicester; Leicester UK
| | - S. W. H. Cowley
- Department of Physics and Astronomy; University of Leicester; Leicester UK
| | - F. Crary
- Southwest Research Institute; San Antonio Texas USA
| | - M. Dougherty
- Blackett Laboratory; Imperial College; London UK
| | - L. Lamy
- LESIA, Observatoire de Paris; UPMC, CNRS, Université Paris Diderot; Meudon France
| | - D. Mitchell
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
| | - W. Pryor
- Department of Science; Central Arizona College; Coolidge Arizona USA
| | | | - T. Stallard
- Department of Physics and Astronomy; University of Leicester; Leicester UK
| | - B. Zieger
- AOSS Department; University of Michigan; Ann Arbor Michigan USA
| | - P. Zarka
- LESIA, Observatoire de Paris; UPMC, CNRS, Université Paris Diderot; Meudon France
| | - B. Cecconi
- LESIA, Observatoire de Paris; UPMC, CNRS, Université Paris Diderot; Meudon France
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Cecconi B, Lamy L, Zarka P, Prangé R, Kurth WS, Louarn P. Goniopolarimetric study of the revolution 29 perikrone using the Cassini Radio and Plasma Wave Science instrument high-frequency radio receiver. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008ja013830] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- B. Cecconi
- LESIA, Observatoire de Paris; CNRS, UPMC, Université Paris Diderot; Meudon France
| | - L. Lamy
- LESIA, Observatoire de Paris; CNRS, UPMC, Université Paris Diderot; Meudon France
| | - P. Zarka
- LESIA, Observatoire de Paris; CNRS, UPMC, Université Paris Diderot; Meudon France
| | - R. Prangé
- LESIA, Observatoire de Paris; CNRS, UPMC, Université Paris Diderot; Meudon France
| | - W. S. Kurth
- Department of Physics and Astronomy; University of Iowa; Iowa City Iowa USA
| | - P. Louarn
- Centre d'Etude Spatiale des Rayonnements; Université Paul Saltier, CNRS; Toulouse France
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Radioti A, Grodent D, Gérard JC, Roussos E, Paranicas C, Bonfond B, Mitchell DG, Krupp N, Krimigis S, Clarke JT. Transient auroral features at Saturn: Signatures of energetic particle injections in the magnetosphere. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008ja013632] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- A. Radioti
- Laboratoire de Physique Atmosphérique et Planétaire, Institut d'Astrophysique et de Géophysique; Université de Liège; Liege Belgium
| | - D. Grodent
- Laboratoire de Physique Atmosphérique et Planétaire, Institut d'Astrophysique et de Géophysique; Université de Liège; Liege Belgium
| | - J.-C. Gérard
- Laboratoire de Physique Atmosphérique et Planétaire, Institut d'Astrophysique et de Géophysique; Université de Liège; Liege Belgium
| | - E. Roussos
- Max-Planck-Institut für Sonnensystemforschung; Katlenburg-Lindau Germany
| | - C. Paranicas
- Applied Physics Laboratory; Johns Hopkins University; Laurel Maryland USA
| | - B. Bonfond
- Laboratoire de Physique Atmosphérique et Planétaire, Institut d'Astrophysique et de Géophysique; Université de Liège; Liege Belgium
| | - D. G. Mitchell
- Applied Physics Laboratory; Johns Hopkins University; Laurel Maryland USA
| | - N. Krupp
- Max-Planck-Institut für Sonnensystemforschung; Katlenburg-Lindau Germany
| | - S. Krimigis
- Applied Physics Laboratory; Johns Hopkins University; Laurel Maryland USA
- Office for Space Research and Applications; Academy of Athens; Athens Greece
| | - J. T. Clarke
- Center for Space Physics; Boston University; Boston Massachusetts USA
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Nichols JD, Clarke JT, Cowley SWH, Duval J, Farmer AJ, Gérard JC, Grodent D, Wannawichian S. Oscillation of Saturn's southern auroral oval. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2008ja013444] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- J. D. Nichols
- Center for Space Physics; Boston University; Boston Massachusetts USA
- Department of Physics and Astronomy; University of Leicester; Leicester UK
| | - J. T. Clarke
- Center for Space Physics; Boston University; Boston Massachusetts USA
| | - S. W. H. Cowley
- Department of Physics and Astronomy; University of Leicester; Leicester UK
| | - J. Duval
- Center for Space Physics; Boston University; Boston Massachusetts USA
| | - A. J. Farmer
- Harvard-Smithsonian Center for Astrophysics; Harvard University; Cambridge Massachusetts USA
| | - J.-C. Gérard
- Institut d'Astrophysique et de Géophysique; Université de Liège; Liege Belgium
| | - D. Grodent
- Institut d'Astrophysique et de Géophysique; Université de Liège; Liege Belgium
| | - S. Wannawichian
- Center for Space Physics; Boston University; Boston Massachusetts USA
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Lamy L, Zarka P, Cecconi B, Hess S, Prangé R. Modeling of Saturn kilometric radiation arcs and equatorial shadow zone. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2008ja013464] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- L. Lamy
- LESIA, Observatoire de Paris; CNRS, UPMC, Université Paris Diderot; Meudon France
| | - P. Zarka
- LESIA, Observatoire de Paris; CNRS, UPMC, Université Paris Diderot; Meudon France
| | - B. Cecconi
- LESIA, Observatoire de Paris; CNRS, UPMC, Université Paris Diderot; Meudon France
| | - S. Hess
- LESIA, Observatoire de Paris; CNRS, UPMC, Université Paris Diderot; Meudon France
- LUTH, Observatoire de Paris; CNRS, UPMC; Meudon France
| | - R. Prangé
- LESIA, Observatoire de Paris; CNRS, UPMC, Université Paris Diderot; Meudon France
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Bunce EJ, Arridge CS, Clarke JT, Coates AJ, Cowley SWH, Dougherty MK, Gérard JC, Grodent D, Hansen KC, Nichols JD, Southwood DJ, Talboys DL. Origin of Saturn's aurora: Simultaneous observations by Cassini and the Hubble Space Telescope. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2008ja013257] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- E. J. Bunce
- Department of Physics and Astronomy; University of Leicester; Leicester UK
| | - C. S. Arridge
- Mullard Space Science Laboratory; University College London; Dorking UK
| | - J. T. Clarke
- Center for Space Physics; Boston University; Boston Massachusetts USA
| | - A. J. Coates
- Mullard Space Science Laboratory; University College London; Dorking UK
| | - S. W. H. Cowley
- Department of Physics and Astronomy; University of Leicester; Leicester UK
| | | | - J.-C. Gérard
- Laboratoire de Physique Atmosphérique et Planétaire; Université de Liège; Liège Belgium
| | - D. Grodent
- Laboratoire de Physique Atmosphérique et Planétaire; Université de Liège; Liège Belgium
| | - K. C. Hansen
- Department of Atmospheric, Oceanic, and Space Sciences; University of Michigan; Ann Arbor Michigan USA
| | - J. D. Nichols
- Center for Space Physics; Boston University; Boston Massachusetts USA
| | - D. J. Southwood
- Blackett Laboratory; Imperial College; London UK
- European Space Agency, HQ; Paris France
| | - D. L. Talboys
- Department of Physics and Astronomy; University of Leicester; Leicester UK
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Carbary JF, Mitchell DG, Brandt P, Roelof EC, Krimigis SM. Statistical morphology of ENA emissions at Saturn. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007ja012873] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- J. F. Carbary
- Johns Hopkins University, Applied Physics Laboratory; Laurel Maryland USA
| | - D. G. Mitchell
- Johns Hopkins University, Applied Physics Laboratory; Laurel Maryland USA
| | - P. Brandt
- Johns Hopkins University, Applied Physics Laboratory; Laurel Maryland USA
| | - E. C. Roelof
- Johns Hopkins University, Applied Physics Laboratory; Laurel Maryland USA
| | - S. M. Krimigis
- Johns Hopkins University, Applied Physics Laboratory; Laurel Maryland USA
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Gérard JC, Grodent D, Cowley SWH, Mitchell DG, Kurth WS, Clarke JT, Bunce EJ, Nichols JD, Dougherty MK, Crary FJ, Coates AJ. Saturn's auroral morphology and activity during quiet magnetospheric conditions. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2006ja011965] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Saur J, Mauk BH, Mitchell DG, Krupp N, Khurana KK, Livi S, Krimigis SM, Newell PT, Williams DJ, Brandt PC, Lagg A, Roussos E, Dougherty MK. Anti-planetward auroral electron beams at Saturn. Nature 2006; 439:699-702. [PMID: 16467832 DOI: 10.1038/nature04401] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2005] [Accepted: 11/02/2005] [Indexed: 11/10/2022]
Abstract
Strong discrete aurorae on Earth are excited by electrons, which are accelerated along magnetic field lines towards the planet. Surprisingly, electrons accelerated in the opposite direction have been recently observed. The mechanisms and significance of this anti-earthward acceleration are highly uncertain because only earthward acceleration was traditionally considered, and observations remain limited. It is also unclear whether upward acceleration of the electrons is a necessary part of the auroral process or simply a special feature of Earth's complex space environment. Here we report anti-planetward acceleration of electron beams in Saturn's magnetosphere along field lines that statistically map into regions of aurora. The energy spectrum of these beams is qualitatively similar to the ones observed at Earth, and the energy fluxes in the observed beams are comparable with the energies required to excite Saturn's aurora. These beams, along with the observations at Earth and the barely understood electron beams in Jupiter's magnetosphere, demonstrate that anti-planetward acceleration is a universal feature of aurorae. The energy contained in the beams shows that upward acceleration is an essential part of the overall auroral process.
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Affiliation(s)
- J Saur
- Applied Physics Laboratory, Johns Hopkins University, 11100 Johns Hopkins Road, Laurel, Maryland 20723, USA.
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Sittler EC, Blanc MF, Richardson JD. Proposed model for Saturn's auroral response to the solar wind: Centrifugal instability model. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2005ja011191] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Esposito LW, Colwell JE, Larsen K, McClintock WE, Stewart AIF, Hallett JT, Shemansky DE, Ajello JM, Hansen CJ, Hendrix AR, West RA, Keller HU, Korth A, Pryor WR, Reulke R, Yung YL. Ultraviolet Imaging Spectroscopy Shows an Active Saturnian System. Science 2005; 307:1251-5. [PMID: 15604361 DOI: 10.1126/science.1105606] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Neutral oxygen in the saturnian system shows variability, and the total number of oxygen atoms peaks at 4 x 10(34). Saturn's aurora brightens in response to solar-wind forcing, and the auroral spectrum resembles Jupiter's. Phoebe's surface shows variable water-ice content, and the data indicate it originated in the outer solar system. Saturn's rings also show variable water abundance, with the purest ice in the outermost A ring. This radial variation is consistent with initially pure water ice bombarded by meteors, but smaller radial structures may indicate collisional transport and recent renewal events in the past 10(7) to 10(8) years.
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Affiliation(s)
- Larry W Esposito
- University of Colorado, Laboratory for Atmospheric and Space Physics, 234 Innovation Drive, Boulder, CO 80303-7814, USA.
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Badman SV, Bunce EJ, Clarke JT, Cowley SWH, Gérard JC, Grodent D, Milan SE. Open flux estimates in Saturn's magnetosphere during the January 2004 Cassini-HST campaign, and implications for reconnection rates. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2005ja011240] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Cowley SWH. Reconnection in a rotation-dominated magnetosphere and its relation to Saturn's auroral dynamics. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2004ja010796] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Gérard JC, Bunce EJ, Grodent D, Cowley SWH, Clarke JT, Badman SV. Signature of Saturn's auroral cusp: Simultaneous Hubble Space Telescope FUV observations and upstream solar wind monitoring. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2005ja011094] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Jackman CM. Interplanetary conditions and magnetospheric dynamics during the Cassini orbit insertion fly-through of Saturn's magnetosphere. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2005ja011054] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Milan SE. Implications of rapid planetary rotation for the Dungey magnetotail of Saturn. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2004ja010716] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Jackman CM. Interplanetary magnetic field at ∼9 AU during the declining phase of the solar cycle and its implications for Saturn's magnetospheric dynamics. ACTA ACUST UNITED AC 2004. [DOI: 10.1029/2004ja010614] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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