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Wu SY, Ye SY, Fischer G, Taubenschuss U, Jackman CM, O'Dwyer E, Kurth WS, Yao S, Yao ZH, Menietti JD, Xu Y, Long MY, Cecconi B. Saturn Anomalous Myriametric Radiation, a New Type of Saturn Radio Emission Revealed by Cassini. GEOPHYSICAL RESEARCH LETTERS 2022; 49:e2022GL099237. [PMID: 36249464 PMCID: PMC9541930 DOI: 10.1029/2022gl099237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 07/28/2022] [Accepted: 08/01/2022] [Indexed: 06/16/2023]
Abstract
A new radio component namely Saturn Anomalous Myriametric Radiation (SAM) is reported. A total of 193 SAM events have been identified by using all the Cassini Saturn orbital data. SAM emissions are L-O mode radio emission and occasionally accompanied by a first harmonic in R-X mode. SAM's intensities decrease with increasing distance from Saturn, suggesting a source near Saturn. SAM has a typical central frequency near 13 kHz, a bandwidth greater than 8 kHz and usually drifts in frequency over time. SAM's duration can extend to near 11 hr and even longer. These features distinguish SAM from the regular narrowband emissions observed in the nearby frequency range, hence the name anomalous. The high occurrence rate of SAM after low frequency extensions of Saturn Kilometric Radiation and the SAM cases observed during compressions of Saturn's magnetosphere suggest a special connection to solar wind dynamics and magnetospheric conditions at Saturn.
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Affiliation(s)
- S. Y. Wu
- Department of Earth and Space SciencesSouthern University of Science and TechnologyShenzhenPeople's Republic of China
- LESIAObservatoire de ParisUniversité PSLCNRSSorbonne UniversitéUniversité de ParisMeudonFrance
| | - S. Y. Ye
- Department of Earth and Space SciencesSouthern University of Science and TechnologyShenzhenPeople's Republic of China
| | - G. Fischer
- Space Research InstituteAustrian Academy of SciencesGrazAustria
| | - U. Taubenschuss
- Department of Space PhysicsInstitute of Atmospheric Physics of the Czech Academy of SciencesPragueCzechia
| | - C. M. Jackman
- School of Cosmic PhysicsDIAS Dunsink ObservatoryDublin Institute for Advanced StudiesDublinIreland
| | - E. O'Dwyer
- School of Cosmic PhysicsDIAS Dunsink ObservatoryDublin Institute for Advanced StudiesDublinIreland
| | - W. S. Kurth
- Department of Physics and AstronomyUniversity of IowaIowa CityIAUSA
| | - S. Yao
- School of Geophysics and Information TechnologyChina University of Geosciences (Beijing)BeijingPeople's Republic of China
| | - Z. H. Yao
- Key Laboratory of Earth and Planetary PhysicsInstitute of Geology and GeophysicsChinese Academy of SciencesBeijingPeople's Republic of China
| | - J. D. Menietti
- Department of Physics and AstronomyUniversity of IowaIowa CityIAUSA
| | - Y. Xu
- Key Laboratory of Earth and Planetary PhysicsInstitute of Geology and GeophysicsChinese Academy of SciencesBeijingPeople's Republic of China
| | - M. Y. Long
- Department of Space PhysicsSchool of Electronic InformationWuhan UniversityWuhanPeople's Republic of China
| | - B. Cecconi
- LESIAObservatoire de ParisUniversité PSLCNRSSorbonne UniversitéUniversité de ParisMeudonFrance
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Wu SY, Ye SY, Fischer G, Jackman CM, Wang J, Menietti JD, Cecconi B, Long MY. Reflection and Refraction of the L-O Mode 5 kHz Saturn Narrowband Emission by the Magnetosheath. GEOPHYSICAL RESEARCH LETTERS 2022; 49:e2021GL096990. [PMID: 35859935 PMCID: PMC9285440 DOI: 10.1029/2021gl096990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 02/10/2022] [Accepted: 02/12/2022] [Indexed: 06/15/2023]
Abstract
The reflection-by-sheath mechanism of 5 kHz narrowband emissions (NB) at Saturn is confirmed by Cassini observations during several crossings of the magnetopause, which show that the 5 kHz NB can be prevented from escaping Saturn's magnetosphere. The L-O mode 5 kHz NB remained visible in areas of low plasma density but disappeared in regions of high plasma density. In three cases, NB disappeared immediately after the crossings of Saturn's magnetopause. A possible reflected NB event observed near the magnetosheath is discussed. This mechanism can help explain the 5 kHz NB observed at low latitudes outside the Enceladus plasma torus and their upper frequency limit variations. This mechanism significantly improves the current understanding of the 5 kHz NB.
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Affiliation(s)
- S. Y. Wu
- Department of Earth and Space SciencesSouthern University of Science and TechnologyShenzhenPeople's Republic of China
| | - S. Y. Ye
- Department of Earth and Space SciencesSouthern University of Science and TechnologyShenzhenPeople's Republic of China
| | - G. Fischer
- Space Research InstituteAustrian Academy of SciencesGrazAustria
| | - C. M. Jackman
- School of Cosmic PhysicsDublin Institute for Advanced StudiesDublinIreland
| | - J. Wang
- Department of Earth and Space SciencesSouthern University of Science and TechnologyShenzhenPeople's Republic of China
| | - J. D. Menietti
- Department of Physics and AstronomyUniversity of IowaIowa CityIAUSA
| | - B. Cecconi
- LESIA, Observatoire de ParisUniversité PSLCNRSSorbonne UniversitéUniversité de Paris MeudonParisFrance
| | - M. Y. Long
- Department of Space PhysicsSchool of Electronic InformationWuhan UniversityWuhanPeople's Republic of China
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Lamy L, Zarka P, Cecconi B, Prangé R, Kurth WS, Hospodarsky G, Persoon A, Morooka M, Wahlund JE, Hunt GJ. The low-frequency source of Saturn’s kilometric radiation. Science 2018; 362:362/6410/eaat2027. [DOI: 10.1126/science.aat2027] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 09/04/2018] [Indexed: 11/02/2022]
Abstract
Understanding how auroral radio emissions are produced by magnetized bodies requires in situ measurements within their source region. Saturn’s kilometric radiation (SKR) has been widely used as a remote proxy of Saturn’s magnetosphere. We present wave and plasma measurements from the Cassini spacecraft during its ring-grazing high-inclination orbits, which passed three times through the high-altitude SKR emission region. Northern dawn-side, narrow-banded radio sources were encountered at frequencies of 10 to 20 kilohertz, within regions of upward currents mapping to the ultraviolet auroral oval. The kilometric waves were produced on the extraordinary mode by the cyclotron maser instability from 6– to 12–kilo–electron volt electron beams and radiated quasi-perpendicularly to the auroral magnetic field lines. The SKR low-frequency sources appear to be strongly controlled by time-variable magnetospheric electron densities.
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Smith AW, Jackman CM, Thomsen MF. Magnetic reconnection in Saturn's magnetotail: A comprehensive magnetic field survey. JOURNAL OF GEOPHYSICAL RESEARCH. SPACE PHYSICS 2016; 121:2984-3005. [PMID: 27867795 PMCID: PMC5111619 DOI: 10.1002/2015ja022005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 02/01/2016] [Accepted: 03/03/2016] [Indexed: 05/04/2023]
Abstract
Reconnection within planetary magnetotails is responsible for locally energizing particles and changing the magnetic topology. Its role in terms of global magnetospheric dynamics can involve changing the mass and flux content of the magnetosphere. We have identified reconnection related events in spacecraft magnetometer data recorded during Cassini's exploration of Saturn's magnetotail. The events are identified from deflections in the north-south component of the magnetic field, significant above a background level. Data were selected to provide full tail coverage, encompassing the dawn and dusk flanks as well as the deepest midnight orbits. Overall 2094 reconnection related events were identified, with an average rate of 5.0 events per day. The majority of events occur in clusters (within 3 h of other events). We examine changes in this rate in terms of local time and latitude coverage, taking seasonal effects into account. The observed reconnection rate peaks postmidnight with more infrequent but steady loss seen on the dusk flank. We estimate the mass loss from the event catalog and find it to be insufficient to balance the input from the moon Enceladus. Several reasons for this discrepancy are discussed. The reconnection X line location appears to be highly variable, though a statistical separation between events tailward and planetward of the X line is observed at a radial distance of between 20 and 30RS downtail. The small sample size at dawn prevents comprehensive statistical comparison with the dusk flank observations in terms of flux closure.
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Affiliation(s)
- A. W. Smith
- Department of Physics and AstronomyUniversity of SouthamptonSouthamptonUK
| | - C. M. Jackman
- Department of Physics and AstronomyUniversity of SouthamptonSouthamptonUK
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Jia X, Hansen KC, Gombosi TI, Kivelson MG, Tóth G, DeZeeuw DL, Ridley AJ. Magnetospheric configuration and dynamics of Saturn's magnetosphere: A global MHD simulation. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2012ja017575] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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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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Menietti JD, Mutel RL, Schippers P, Ye SY, Gurnett DA, Lamy L. Analysis of Saturn kilometric radiation near a source center. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011ja017056] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- J. D. Menietti
- Department of Physics and Astronomy; University of Iowa; Iowa City Iowa USA
| | - R. L. Mutel
- Department of Physics and Astronomy; University of Iowa; Iowa City Iowa USA
| | - P. Schippers
- Department of Physics and Astronomy; University of Iowa; Iowa City Iowa USA
| | - S.-Y. Ye
- Department of Physics and Astronomy; University of Iowa; Iowa City Iowa USA
| | - D. A. Gurnett
- Department of Physics and Astronomy; University of Iowa; Iowa City Iowa USA
| | - L. Lamy
- LESIA, Observatoire de Paris; Université Paris Diderot, UPMC, CNRS; Meudon France
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Arridge CS, André N, Khurana KK, Russell CT, Cowley SWH, Provan G, Andrews DJ, Jackman CM, Coates AJ, Sittler EC, Dougherty MK, Young DT. Periodic motion of Saturn's nightside plasma sheet. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011ja016827] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- C. S. Arridge
- Mullard Space Science Laboratory; University College London; Dorking UK
- Centre for Planetary Sciences at UCL/Birkbeck; London UK
| | - N. André
- Institut de Recherche en Astrophysique et Planétologie; CNRS; Toulouse France
- Institut de Recherche en Astrophysique et Planétologie; Université de Toulouse, UPS-OMP; Toulouse France
| | - K. K. Khurana
- Institute for Geophysics and Planetary Physics; University of California; Los Angeles California USA
| | - C. T. Russell
- Institute for Geophysics and Planetary Physics; University of California; Los Angeles California USA
| | - S. W. H. Cowley
- Department of Physics and Astronomy; University of Leicester; Leicester UK
| | - G. Provan
- Department of Physics and Astronomy; University of Leicester; Leicester UK
| | - D. J. Andrews
- Department of Physics and Astronomy; University of Leicester; Leicester UK
| | - C. M. Jackman
- Centre for Planetary Sciences at UCL/Birkbeck; London UK
- Blackett Laboratory; Imperial College London; London UK
- Department of Physics and Astronomy; University College London; London UK
| | - A. J. Coates
- Mullard Space Science Laboratory; University College London; Dorking UK
- Centre for Planetary Sciences at UCL/Birkbeck; London UK
| | - E. C. Sittler
- NASA Goddard Space Flight Center; Greenbelt Maryland USA
| | | | - D. T. Young
- Southwest Research Institute; San Antonio Texas USA
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Szego K, Nemeth Z, Erdos G, Foldy L, Thomsen M, Delapp D. The plasma environment of Titan: The magnetodisk of Saturn near the encounters as derived from ion densities measured by the Cassini/CAPS plasma spectrometer. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011ja016629] [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)
- K. Szego
- KFKI Research Institute for Particle and Nuclear Physics; Budapest Hungary
| | - Z. Nemeth
- KFKI Research Institute for Particle and Nuclear Physics; Budapest Hungary
| | - G. Erdos
- KFKI Research Institute for Particle and Nuclear Physics; Budapest Hungary
| | - L. Foldy
- KFKI Research Institute for Particle and Nuclear Physics; Budapest Hungary
| | - M. Thomsen
- Los Alamos National Laboratory; Los Alamos New Mexico USA
| | - D. Delapp
- Los Alamos National Laboratory; Los Alamos New Mexico USA
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Jackman CM, Slavin JA, Cowley SWH. Cassini observations of plasmoid structure and dynamics: Implications for the role of magnetic reconnection in magnetospheric circulation at Saturn. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011ja016682] [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)
- C. M. Jackman
- Department of Physics and Astronomy; University College London; London UK
| | - J. A. Slavin
- NASA Goddard Space Flight Center; Greenbelt Maryland USA
| | - S. W. H. Cowley
- Department of Physics and Astronomy; University of Leicester; Leicester UK
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Jackman CM, Arridge CS. Statistical properties of the magnetic field in the Kronian magnetotail lobes and current sheet. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010ja015973] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- C. M. Jackman
- Blackett Laboratory; Imperial College London; London UK
| | - C. S. Arridge
- Mullard Space Science Laboratory; University College London; Dorking UK
- Centre for Planetary Sciences at UCL/Birkbeck; London UK
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Sergis N, Arridge CS, Krimigis SM, Mitchell DG, Rymer AM, Hamilton DC, Krupp N, Dougherty MK, Coates AJ. Dynamics and seasonal variations in Saturn's magnetospheric plasma sheet, as measured by Cassini. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010ja016180] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- N. Sergis
- Office of Space Research and Technology; Academy of Athens; Athens Greece
| | - C. S. Arridge
- Mullard Space Science Laboratory, Department of Space and Climate Physics; University College London; London UK
- Centre for Planetary Sciences at UCL/Birkbeck; London UK
| | - S. M. Krimigis
- Office of Space Research and Technology; Academy of Athens; Athens Greece
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
| | - D. G. Mitchell
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
| | - A. M. Rymer
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
| | - D. C. Hamilton
- Department of Physics; University of Maryland; College Park Maryland USA
| | - N. Krupp
- Max Planck Institute for Solar System Research; Katlenburg-Lindau Germany
| | - M. K. Dougherty
- Space and Atmospheric Physics Group, Blackett Laboratory; Imperial College London; London UK
| | - A. J. Coates
- Mullard Space Science Laboratory, Department of Space and Climate Physics; University College London; London UK
- Centre for Planetary Sciences at UCL/Birkbeck; London UK
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