1
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Kurth WS, Sulaiman AH, Hospodarsky GB, Menietti JD, Mauk BH, Clark G, Allegrini F, Valek P, Connerney JEP, Waite JH, Bolton SJ, Imai M, Santolik O, Li W, Duling S, Saur J, Louis C. Juno Plasma Wave Observations at Ganymede. Geophys Res Lett 2022; 49:e2022GL098591. [PMID: 37034392 PMCID: PMC10078157 DOI: 10.1029/2022gl098591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 04/22/2022] [Accepted: 04/27/2022] [Indexed: 06/19/2023]
Abstract
The Juno Waves instrument measured plasma waves associated with Ganymede's magnetosphere during its flyby on 7 June, day 158, 2021. Three distinct regions were identified including a wake, and nightside and dayside regions in the magnetosphere distinguished by their electron densities and associated variability. The magnetosphere includes electron cyclotron harmonic emissions including a band at the upper hybrid frequency, as well as whistler-mode chorus and hiss. These waves likely interact with energetic electrons in Ganymede's magnetosphere by pitch angle scattering and/or accelerating the electrons. The wake is accentuated by low-frequency turbulence and electrostatic solitary waves. Radio emissions observed before and after the flyby likely have their source in Ganymede's magnetosphere.
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Affiliation(s)
- W. S. Kurth
- Department of Physics and AstronomyUniversity of IowaIowa CityIAUSA
| | - A. H. Sulaiman
- Department of Physics and AstronomyUniversity of IowaIowa CityIAUSA
| | | | - J. D. Menietti
- Department of Physics and AstronomyUniversity of IowaIowa CityIAUSA
| | - B. H. Mauk
- The Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - G. Clark
- The Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - F. Allegrini
- Southwest Research InstituteSan AntonioTXUSA
- Department of Physics and AstronomyUniversity of Texas at San AntonioSan AntonioTXUSA
| | - P. Valek
- Southwest Research InstituteSan AntonioTXUSA
| | | | - J. H. Waite
- Southwest Research InstituteSan AntonioTXUSA
| | | | - M. Imai
- Department of Electrical Engineering and Information ScienceNational Institute of Technology (KOSEN), Niihama CollegeNiihamaJapan
| | - O. Santolik
- Department of Space PhysicsInstitute of Atmospheric Physics of the Czech Academy of SciencesPragueCzechia
- Faculty of Mathematics and PhysicsCharles UniversityPragueCzechia
| | - W. Li
- Center for Space PhysicsBoston UniversityBostonMAUSA
| | - S. Duling
- Institute of Geophysics and MeteorologyUniversity of CologneCologneGermany
| | - J. Saur
- Institute of Geophysics and MeteorologyUniversity of CologneCologneGermany
| | - C. Louis
- School of Cosmic Physics, DIAS Dunsink ObservatoryDublin Institute for Advanced StudiesDublinIreland
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2
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Chakraborty S, Mann IR, Watt CEJ, Rae IJ, Olifer L, Ozeke LG, Sandhu JK, Mauk BH, Spence H. Intense chorus waves are the cause of flux-limiting in the heart of the outer radiation belt. Sci Rep 2022; 12:21717. [PMID: 36522393 PMCID: PMC9755534 DOI: 10.1038/s41598-022-26189-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022] Open
Abstract
Chorus waves play a key role in outer Van Allen electron belt dynamics through cyclotron resonance. Here, we use Van Allen Probes data to reveal a new and distinct population of intense chorus waves excited in the heart of the radiation belt during the main phase of geomagnetic storms. The power of the waves is typically ~ 2-3 orders of magnitude greater than pre-storm levels, and are generated when fluxes of ~ 10-100 keV electrons approach or exceed the Kennel-Petschek limit. These intense chorus waves rapidly scatter electrons into the loss cone, capping the electron flux to a value close to the limit predicted by Kennel and Petschek over 50 years ago. Our results are crucial for understanding the limits to radiation belt fluxes, with accurate models likely requiring the inclusion of this chorus wave-driven flux-limiting process, that is independent of the acceleration mechanism or source responsible for enhancing the flux.
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Affiliation(s)
- S. Chakraborty
- grid.42629.3b0000000121965555Department of Mathematics, Physics and Electrical Engineering, Northumbria University, Newcastle upon Tyne, UK
| | - I. R. Mann
- grid.42629.3b0000000121965555Department of Mathematics, Physics and Electrical Engineering, Northumbria University, Newcastle upon Tyne, UK ,grid.17089.370000 0001 2190 316XDepartment of Physics, University of Alberta, Edmonton, AB Canada
| | - C. E. J. Watt
- grid.42629.3b0000000121965555Department of Mathematics, Physics and Electrical Engineering, Northumbria University, Newcastle upon Tyne, UK
| | - I. J. Rae
- grid.42629.3b0000000121965555Department of Mathematics, Physics and Electrical Engineering, Northumbria University, Newcastle upon Tyne, UK
| | - L. Olifer
- grid.17089.370000 0001 2190 316XDepartment of Physics, University of Alberta, Edmonton, AB Canada
| | - L. G. Ozeke
- grid.17089.370000 0001 2190 316XDepartment of Physics, University of Alberta, Edmonton, AB Canada
| | - J. K. Sandhu
- grid.42629.3b0000000121965555Department of Mathematics, Physics and Electrical Engineering, Northumbria University, Newcastle upon Tyne, UK
| | - B. H. Mauk
- grid.21107.350000 0001 2171 9311Applied Physics Laboratory, Johns Hopkins University, Laurel, MD USA
| | - H. Spence
- grid.167436.10000 0001 2192 7145Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH USA
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3
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Sulaiman AH, Mauk BH, Szalay JR, Allegrini F, Clark G, Gladstone GR, Kotsiaros S, Kurth WS, Bagenal F, Bonfond B, Connerney JEP, Ebert RW, Elliott SS, Gershman DJ, Hospodarsky GB, Hue V, Lysak RL, Masters A, Santolík O, Saur J, Bolton SJ. Jupiter's Low-Altitude Auroral Zones: Fields, Particles, Plasma Waves, and Density Depletions. J Geophys Res Space Phys 2022; 127:e2022JA030334. [PMID: 36247326 PMCID: PMC9539694 DOI: 10.1029/2022ja030334] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 06/15/2022] [Accepted: 07/21/2022] [Indexed: 06/16/2023]
Abstract
The Juno spacecraft's polar orbits have enabled direct sampling of Jupiter's low-altitude auroral field lines. While various data sets have identified unique features over Jupiter's main aurora, they are yet to be analyzed altogether to determine how they can be reconciled and fit into the bigger picture of Jupiter's auroral generation mechanisms. Jupiter's main aurora has been classified into distinct "zones", based on repeatable signatures found in energetic electron and proton spectra. We combine fields, particles, and plasma wave data sets to analyze Zone-I and Zone-II, which are suggested to carry upward and downward field-aligned currents, respectively. We find Zone-I to have well-defined boundaries across all data sets. H+ and/or H3 + cyclotron waves are commonly observed in Zone-I in the presence of energetic upward H+ beams and downward energetic electron beams. Zone-II, on the other hand, does not have a clear poleward boundary with the polar cap, and its signatures are more sporadic. Large-amplitude solitary waves, which are reminiscent of those ubiquitous in Earth's downward current region, are a key feature of Zone-II. Alfvénic fluctuations are most prominent in the diffuse aurora and are repeatedly found to diminish in Zone-I and Zone-II, likely due to dissipation, at higher altitudes, to energize auroral electrons. Finally, we identify significant electron density depletions, by up to 2 orders of magnitude, in Zone-I, and discuss their important implications for the development of parallel potentials, Alfvénic dissipation, and radio wave generation.
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Affiliation(s)
- A. H. Sulaiman
- Department of Physics and AstronomyUniversity of IowaIowa CityIAUSA
| | - B. H. Mauk
- Applied Physics LaboratoryJohns Hopkins UniversityLaurelMDUSA
| | - J. R. Szalay
- Department of Astrophysical SciencesPrinceton UniversityPrincetonNJUSA
| | - F. Allegrini
- Southwest Research InstituteSan AntonioTXUSA
- Department of Physics and AstronomyUniversity of Texas at San AntonioSan AntonioTXUSA
| | - G. Clark
- Applied Physics LaboratoryJohns Hopkins UniversityLaurelMDUSA
| | - G. R. Gladstone
- Southwest Research InstituteSan AntonioTXUSA
- Department of Physics and AstronomyUniversity of Texas at San AntonioSan AntonioTXUSA
| | - S. Kotsiaros
- DTU‐SpaceTechnical University of DenmarkKongens LyngbyDenmark
| | - W. S. Kurth
- Department of Physics and AstronomyUniversity of IowaIowa CityIAUSA
| | - F. Bagenal
- Laboratory for Atmospheric and Space PhysicsUniversity of Colorado BoulderBoulderCOUSA
| | - B. Bonfond
- Space SciencesTechnologies and Astrophysics Research InstituteLPAPUniversité de LiègeLiègeBelgium
| | - J. E. P. Connerney
- Space Research CorporationAnnapolisMDUSA
- NASA/Goddard Space Flight CenterGreenbeltMDUSA
| | - R. W. Ebert
- Southwest Research InstituteSan AntonioTXUSA
- Department of Physics and AstronomyUniversity of Texas at San AntonioSan AntonioTXUSA
| | - S. S. Elliott
- Minnetota Institute for AstrophysicsSchool of Physics and AstronomyUniversity of MinnesotaMinneapolisMNUSA
| | | | | | - V. Hue
- Southwest Research InstituteSan AntonioTXUSA
| | - R. L. Lysak
- Minnetota Institute for AstrophysicsSchool of Physics and AstronomyUniversity of MinnesotaMinneapolisMNUSA
| | - A. Masters
- Blackett LaboratoryImperial College LondonLondonUK
| | - O. Santolík
- Department of Space PhysicsInstitute of Atmospheric Physics of the Czech Academy of SciencesPragueCzechia
- Faculty of Mathematics and PhysicsCharles UniversityPragueCzechia
| | - J. Saur
- Institute of Geophysics and MeteorologyUniversity of CologneCologneGermany
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4
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Szalay JR, Clark G, Livadiotis G, McComas DJ, Mitchell DG, Rankin JS, Sulaiman AH, Allegrini F, Bagenal F, Ebert RW, Gladstone GR, Kurth WS, Mauk BH, Valek PW, Wilson RJ, Bolton SJ. Closed Fluxtubes and Dispersive Proton Conics at Jupiter's Polar Cap. Geophys Res Lett 2022; 49:e2022GL098741. [PMID: 35859815 PMCID: PMC9285739 DOI: 10.1029/2022gl098741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 04/14/2022] [Accepted: 04/16/2022] [Indexed: 05/08/2023]
Abstract
Two distinct proton populations are observed over Jupiter's southern polar cap: a ∼1 keV core population and ∼1-300 keV dispersive conic population at 6-7 RJ planetocentric distance. We find the 1 keV core protons are likely the seed population for the higher-energy dispersive conics, which are accelerated from a distance of ∼3-5 RJ. Transient wave-particle heating in a "pressure-cooker" process is likely responsible for this proton acceleration. The plasma characteristics and composition during this period show Jupiter's polar-most field lines can be topologically closed, with conjugate magnetic footpoints connected to both hemispheres. Finally, these observations demonstrate energetic protons can be accelerated into Jupiter's magnetotail via wave-particle coupling.
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Affiliation(s)
- J. R. Szalay
- Department of Astrophysical SciencesPrinceton UniversityPrincetonNJUSA
| | - G. Clark
- The Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - G. Livadiotis
- Department of Astrophysical SciencesPrinceton UniversityPrincetonNJUSA
| | - D. J. McComas
- Department of Astrophysical SciencesPrinceton UniversityPrincetonNJUSA
| | - D. G. Mitchell
- The Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - J. S. Rankin
- Department of Astrophysical SciencesPrinceton UniversityPrincetonNJUSA
| | | | - F. Allegrini
- Southwest Research InstituteSan AntonioTXUSA
- Department of Physics and AstronomyUniversity of Texas at San AntonioSan AntonioTXUSA
| | - F. Bagenal
- Laboratory for Atmospheric and Space PhysicsUniversity of Colorado BoulderBoulderCOUSA
| | - R. W. Ebert
- Southwest Research InstituteSan AntonioTXUSA
- Department of Physics and AstronomyUniversity of Texas at San AntonioSan AntonioTXUSA
| | | | | | - B. H. Mauk
- The Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - P. W. Valek
- Southwest Research InstituteSan AntonioTXUSA
| | - R. J. Wilson
- Laboratory for Atmospheric and Space PhysicsUniversity of Colorado BoulderBoulderCOUSA
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5
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Bingham ST, Cohen IJ, Mauk BH, Turner DL, Mitchell DG, Vines SK, Fuselier SA, Torbert RB, Burch JL. Charge-State-Dependent Energization of Suprathermal Ions During Substorm Injections Observed by MMS in the Magnetotail. J Geophys Res Space Phys 2020; 125:e2020JA028144. [PMID: 33133997 PMCID: PMC7583365 DOI: 10.1029/2020ja028144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 06/26/2020] [Accepted: 07/22/2020] [Indexed: 06/11/2023]
Abstract
Understanding the energization processes and constituent composition of the plasma and energetic particles injected into the near-Earth region from the tail is an important component of understanding magnetospheric dynamics. In this study, we present multiple case studies of the high-energy (≳40 keV) suprathermal ion populations during energetic particle enhancement events observed by the Energetic Ion Spectrometer (EIS) on NASA's Magnetospheric Multiscale (MMS) mission in the magnetotail. We present results from correlation analysis of the flux response between different energy channels of different ion species (hydrogen, helium, and oxygen) for multiple cases. We demonstrate that this technique can be used to infer the dominant charge state of the heavy ions, despite the fact that charge is not directly measured by EIS. Using this technique, we find that the energization and dispersion of suprathermal ions during energetic particle enhancements concurrent with (or near) fast plasma flows are ordered by energy per charge state (E/q) throughout the magnetotail regions examined (~7 to 25 Earth radii). The ions with the highest energies (≳300 keV) are helium and oxygen of solar wind origin, which obtain their greater energization due to their higher charge states. Additionally, the case studies show that during these injections the flux ratio of enhancement is also well ordered by E/q. These results expand on previous results which showed that high-energy total ion measurements in the magnetosphere are dominated by high-charge-state heavy ions and that protons are often not the dominant species above ~300 keV.
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Affiliation(s)
- S. T. Bingham
- The Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - I. J. Cohen
- The Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - B. H. Mauk
- The Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - D. L. Turner
- The Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - D. G. Mitchell
- The Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - S. K. Vines
- The Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - S. A. Fuselier
- Southwest Research InstituteSan AntonioTXUSA
- Department of Physics and AstronomyUniversity of Texas at San AntonioSan AntonioTXUSA
| | - R. B. Torbert
- Southwest Research InstituteSan AntonioTXUSA
- Space Science CenterUniversity of New HampshireDurhamNHUSA
| | - J. L. Burch
- Southwest Research InstituteSan AntonioTXUSA
- Department of Physics and AstronomyUniversity of Texas at San AntonioSan AntonioTXUSA
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6
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Westlake JH, Clark G, Haggerty DK, Jaskulek SE, Kollmann P, Mauk BH, Mitchell DG, Nelson KS, Paranicas CP, Rymer AM. High-Energy (>10 MeV) Oxygen and Sulfur Ions Observed at Jupiter From Pulse Width Measurements of the JEDI Sensors. Geophys Res Lett 2019; 46:10959-10966. [PMID: 31894168 PMCID: PMC6919389 DOI: 10.1029/2019gl083842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 09/03/2019] [Accepted: 09/06/2019] [Indexed: 06/10/2023]
Abstract
The Jovian polar regions produce X-rays that are characteristic of very energetic oxygen and sulfur that become highly charged on precipitating into Jupiter's upper atmosphere. Juno has traversed the polar regions above where these energetic ions are expected to be precipitating revealing a complex composition and energy structure. Energetic ions are likely to drive the characteristic X-rays observed at Jupiter (Haggerty et al., 2017, https://doi.org/10.1002/2017GL072866; Houston et al., 2018, https://doi.org/10.1002/2017JA024872; Kharchenko et al., 2006, https://doi.org/10.1029/2006GL026039). Motivated by the science of X-ray generation, we describe here Juno Jupiter Energetic Particle Detector Instrument (JEDI) measurements of ions above 1 MeV and demonstrate the capability of measuring oxygen and sulfur ions with energies up to 100 MeV. We detail the process of retrieving ion fluxes from pulse width data on instruments like JEDI (called "puck's"; Clark, Cohen, et al., 2016, https://doi.org/10.1002/2017GL074366; Clark, Mauk, et al., 2016, https://doi.org/10.1002/2015JA022257; Mauk et al., 2013, https://doi.org/10.1007/s11214-013-0025-3) as well as details on retrieving very energetic particles (>20 MeV) above which the pulse width also saturates.
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Affiliation(s)
- J. H. Westlake
- Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - G. Clark
- Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - D. K. Haggerty
- Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - S. E. Jaskulek
- Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - P. Kollmann
- Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - B. H. Mauk
- Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - D. G. Mitchell
- Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - K. S. Nelson
- Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - C. P. Paranicas
- Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - A. M. Rymer
- Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
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7
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Haggerty DK, Mauk BH, Paranicas CP, Clark G, Kollmann P, Rymer AM, Gladstone GR, Greathouse TK, Bolton SJ, Levin SM. Jovian Injections Observed at High Latitude. Geophys Res Lett 2019; 46:9397-9404. [PMID: 31762519 PMCID: PMC6853255 DOI: 10.1029/2019gl083442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 07/30/2019] [Accepted: 08/05/2019] [Indexed: 06/10/2023]
Abstract
The polar orbit of Juno at Jupiter provides a unique opportunity to observe high-latitude energetic particle injections. We measure energy-dispersed impulsive injections of protons and electrons. Ion injection signatures are just as prevalent as electron signatures, contrary to previous equatorial observations. Included are previously unreported observations of high-energy banded structures believed to be remnants of much earlier injections, where the particles have had time to disperse around Jupiter. A model fit of the injections used to estimate timing fits the shape of the proton signatures better than it does the electron shapes, suggesting that electrons and protons are different in their abilities to escape the injection region. We present ultaviolet observations of Jupiter's aurora and discuss the relationship between auroral injection features and in situ injection events. We find, unexpectedly, that the presence of in situ particle injections does not necessarily result in auroral injection signatures.
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Affiliation(s)
- D. K. Haggerty
- The Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - B. H. Mauk
- The Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - C. P. Paranicas
- The Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - G. Clark
- The Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - P. Kollmann
- The Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - A. M. Rymer
- The Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
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8
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Cozzani G, Retinò A, Califano F, Alexandrova A, Le Contel O, Khotyaintsev Y, Vaivads A, Fu HS, Catapano F, Breuillard H, Ahmadi N, Lindqvist PA, Ergun RE, Torbert RB, Giles BL, Russell CT, Nakamura R, Fuselier S, Mauk BH, Moore T, Burch JL. In situ spacecraft observations of a structured electron diffusion region during magnetopause reconnection. Phys Rev E 2019; 99:043204. [PMID: 31108651 DOI: 10.1103/physreve.99.043204] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Indexed: 11/07/2022]
Abstract
The electron diffusion region (EDR) is the region where magnetic reconnection is initiated and electrons are energized. Because of experimental difficulties, the structure of the EDR is still poorly understood. A key question is whether the EDR has a homogeneous or patchy structure. Here we report Magnetospheric Multiscale (MMS) spacecraft observations providing evidence of inhomogeneous current densities and energy conversion over a few electron inertial lengths within an EDR at the terrestrial magnetopause, suggesting that the EDR can be rather structured. These inhomogenenities are revealed through multipoint measurements because the spacecraft separation is comparable to a few electron inertial lengths, allowing the entire MMS tetrahedron to be within the EDR most of the time. These observations are consistent with recent high-resolution and low-noise kinetic simulations.
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Affiliation(s)
- Giulia Cozzani
- Laboratoire de Physique des Plasmas, CNRS/Ecole Polytechnique/Sorbonne Université, Université Paris Sud, Observatoire de Paris, 91128 Palaiseau, France.,Dipartimento di Fisica "E. Fermi", Università di Pisa, I-56127 Pisa, Italy
| | - A Retinò
- Laboratoire de Physique des Plasmas, CNRS/Ecole Polytechnique/Sorbonne Université, Université Paris Sud, Observatoire de Paris, 91128 Palaiseau, France
| | - F Califano
- Dipartimento di Fisica "E. Fermi", Università di Pisa, I-56127 Pisa, Italy
| | - A Alexandrova
- Laboratoire de Physique des Plasmas, CNRS/Ecole Polytechnique/Sorbonne Université, Université Paris Sud, Observatoire de Paris, 91128 Palaiseau, France
| | - O Le Contel
- Laboratoire de Physique des Plasmas, CNRS/Ecole Polytechnique/Sorbonne Université, Université Paris Sud, Observatoire de Paris, 91128 Palaiseau, France
| | - Y Khotyaintsev
- Swedish Institute of Space Physics, SE-75121 Uppsala, Sweden
| | - A Vaivads
- Swedish Institute of Space Physics, SE-75121 Uppsala, Sweden
| | - H S Fu
- School of Space and Environment, Beihang University, Beijing, 100083, P.R. China
| | - F Catapano
- Laboratoire de Physique des Plasmas, CNRS/Ecole Polytechnique/Sorbonne Université, Université Paris Sud, Observatoire de Paris, 91128 Palaiseau, France.,Dipartimento di Fisica, Università della Calabria, I-87036, Arcavacata di Rende (CS), Italy
| | - H Breuillard
- Laboratoire de Physique des Plasmas, CNRS/Ecole Polytechnique/Sorbonne Université, Université Paris Sud, Observatoire de Paris, 91128 Palaiseau, France.,Laboratoire de Physique et Chimie de l'Environnement et de l'Espace, CNRS-Université d'Orléans, UMR 7328, 45071 Orléans, France
| | - N Ahmadi
- Laboratory of Atmospheric and Space Physics, University of Colorado Boulder, Boulder, Colorado 80309, USA
| | - P-A Lindqvist
- KTH Royal Institute of Technology, SE-10044, Stockholm, Sweden
| | - R E Ergun
- Laboratory of Atmospheric and Space Physics, University of Colorado Boulder, Boulder, Colorado 80309, USA
| | - R B Torbert
- Space Science Center, University of New Hampshire, Durham, New Hampshire 03824, USA
| | - B L Giles
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - C T Russell
- Department of Earth and Space Sciences, University of California, Los Angeles, California 90095, USA
| | - R Nakamura
- Space Research Institute, Austrian Academy of Sciences, 8042 Graz, Austria
| | - S Fuselier
- Southwest Research Institute, San Antonio, Texas 78238, USA.,University of Texas at San Antonio, San Antonio, Texas 78238, USA
| | - B H Mauk
- The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland 20723, USA
| | - T Moore
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - J L Burch
- Southwest Research Institute, San Antonio, Texas 78238, USA
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9
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Ebert RW, Greathouse TK, Clark G, Allegrini F, Bagenal F, Bolton SJ, Connerney JEP, Gladstone GR, Imai M, Hue V, Kurth WS, Levin S, Louarn P, Mauk BH, McComas DJ, Paranicas C, Szalay JR, Thomsen MF, Valek PW, Wilson RJ. Comparing Electron Energetics and UV Brightness in Jupiter's Northern Polar Region During Juno Perijove 5. Geophys Res Lett 2019; 46:19-27. [PMID: 30828110 PMCID: PMC6378591 DOI: 10.1029/2018gl081129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 12/14/2018] [Accepted: 12/20/2018] [Indexed: 05/24/2023]
Abstract
We compare electron and UV observations mapping to the same location in Jupiter's northern polar region, poleward of the main aurora, during Juno perijove 5. Simultaneous peaks in UV brightness and electron energy flux are identified when observations map to the same location at the same time. The downward energy flux during these simultaneous observations was not sufficient to generate the observed UV brightness; the upward energy flux was. We propose that the primary acceleration region is below Juno's altitude, from which the more intense upward electrons originate. For the complete interval, the UV brightness peaked at ~240 kilorayleigh (kR); the downward and upward energy fluxes peaked at 60 and 700 mW/m2, respectively. Increased downward energy fluxes are associated with increased contributions from tens of keV electrons. These observations provide evidence that bidirectional electron beams with broad energy distributions can produce tens to hundreds of kilorayleigh polar UV emissions.
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Affiliation(s)
- R. W. Ebert
- Southwest Research InstituteSan AntonioTXUSA
- Department of Physics and AstronomyUniversity of Texas at San AntonioSan AntonioTXUSA
| | | | - G. Clark
- Johns Hopkins University Applied Physics LabLaurelMDUSA
| | - F. Allegrini
- Southwest Research InstituteSan AntonioTXUSA
- Department of Physics and AstronomyUniversity of Texas at San AntonioSan AntonioTXUSA
| | - F. Bagenal
- Laboratory for Atmospheric and Space PhysicsUniversity of Colorado BoulderBoulderCOUSA
| | | | | | - G. R. Gladstone
- Southwest Research InstituteSan AntonioTXUSA
- Department of Physics and AstronomyUniversity of Texas at San AntonioSan AntonioTXUSA
| | - M. Imai
- Department of Physics and AstronomyUniversity of IowaIowa CityIAUSA
| | - V. Hue
- Southwest Research InstituteSan AntonioTXUSA
| | - W. S. Kurth
- Department of Physics and AstronomyUniversity of IowaIowa CityIAUSA
| | - S. Levin
- Jet Propulsion LaboratoryPasadenaCAUSA
| | - P. Louarn
- Institut de Recherche en Astrophysique et PlanétologieToulouseFrance
| | - B. H. Mauk
- Johns Hopkins University Applied Physics LabLaurelMDUSA
| | - D. J. McComas
- Southwest Research InstituteSan AntonioTXUSA
- Department of Astrophysical SciencesPrinceton UniversityPrincetonNJUSA
| | - C. Paranicas
- Johns Hopkins University Applied Physics LabLaurelMDUSA
| | - J. R. Szalay
- Department of Astrophysical SciencesPrinceton UniversityPrincetonNJUSA
| | | | - P. W. Valek
- Southwest Research InstituteSan AntonioTXUSA
| | - R. J. Wilson
- Laboratory for Atmospheric and Space PhysicsUniversity of Colorado BoulderBoulderCOUSA
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10
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Ebert RW, Greathouse TK, Clark G, Allegrini F, Bagenal F, Bolton SJ, Connerney JEP, Gladstone GR, Imai M, Hue V, Kurth WS, Levin S, Louarn P, Mauk BH, McComas DJ, Paranicas C, Szalay JR, Thomsen MF, Valek PW, Wilson RJ. Comparing Electron Energetics and UV Brightness in Jupiter's Northern Polar Region During Juno Perijove 5. Geophys Res Lett 2019; 46:19-27. [PMID: 30828110 DOI: 10.1029/2019gl084146] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 12/14/2018] [Accepted: 12/20/2018] [Indexed: 05/24/2023]
Abstract
We compare electron and UV observations mapping to the same location in Jupiter's northern polar region, poleward of the main aurora, during Juno perijove 5. Simultaneous peaks in UV brightness and electron energy flux are identified when observations map to the same location at the same time. The downward energy flux during these simultaneous observations was not sufficient to generate the observed UV brightness; the upward energy flux was. We propose that the primary acceleration region is below Juno's altitude, from which the more intense upward electrons originate. For the complete interval, the UV brightness peaked at ~240 kilorayleigh (kR); the downward and upward energy fluxes peaked at 60 and 700 mW/m2, respectively. Increased downward energy fluxes are associated with increased contributions from tens of keV electrons. These observations provide evidence that bidirectional electron beams with broad energy distributions can produce tens to hundreds of kilorayleigh polar UV emissions.
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Affiliation(s)
- R W Ebert
- Southwest Research Institute San Antonio TX USA
- Department of Physics and Astronomy University of Texas at San Antonio San Antonio TX USA
| | | | - G Clark
- Johns Hopkins University Applied Physics Lab Laurel MD USA
| | - F Allegrini
- Southwest Research Institute San Antonio TX USA
- Department of Physics and Astronomy University of Texas at San Antonio San Antonio TX USA
| | - F Bagenal
- Laboratory for Atmospheric and Space Physics University of Colorado Boulder Boulder CO USA
| | - S J Bolton
- Southwest Research Institute San Antonio TX USA
| | | | - G R Gladstone
- Southwest Research Institute San Antonio TX USA
- Department of Physics and Astronomy University of Texas at San Antonio San Antonio TX USA
| | - M Imai
- Department of Physics and Astronomy University of Iowa Iowa City IA USA
| | - V Hue
- Southwest Research Institute San Antonio TX USA
| | - W S Kurth
- Department of Physics and Astronomy University of Iowa Iowa City IA USA
| | - S Levin
- Jet Propulsion Laboratory Pasadena CA USA
| | - P Louarn
- Institut de Recherche en Astrophysique et Planétologie Toulouse France
| | - B H Mauk
- Johns Hopkins University Applied Physics Lab Laurel MD USA
| | - D J McComas
- Southwest Research Institute San Antonio TX USA
- Department of Astrophysical Sciences Princeton University Princeton NJ USA
| | - C Paranicas
- Johns Hopkins University Applied Physics Lab Laurel MD USA
| | - J R Szalay
- Department of Astrophysical Sciences Princeton University Princeton NJ USA
| | | | - P W Valek
- Southwest Research Institute San Antonio TX USA
| | - R J Wilson
- Laboratory for Atmospheric and Space Physics University of Colorado Boulder Boulder CO USA
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11
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Torbert RB, Burch JL, Phan TD, Hesse M, Argall MR, Shuster J, Ergun RE, Alm L, Nakamura R, Genestreti KJ, Gershman DJ, Paterson WR, Turner DL, Cohen I, Giles BL, Pollock CJ, Wang S, Chen LJ, Stawarz JE, Eastwood JP, Hwang KJ, Farrugia C, Dors I, Vaith H, Mouikis C, Ardakani A, Mauk BH, Fuselier SA, Russell CT, Strangeway RJ, Moore TE, Drake JF, Shay MA, Khotyaintsev YV, Lindqvist PA, Baumjohann W, Wilder FD, Ahmadi N, Dorelli JC, Avanov LA, Oka M, Baker DN, Fennell JF, Blake JB, Jaynes AN, Le Contel O, Petrinec SM, Lavraud B, Saito Y. Electron-scale dynamics of the diffusion region during symmetric magnetic reconnection in space. Science 2018; 362:1391-1395. [PMID: 30442767 DOI: 10.1126/science.aat2998] [Citation(s) in RCA: 158] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 11/06/2018] [Indexed: 11/02/2022]
Abstract
Magnetic reconnection is an energy conversion process that occurs in many astrophysical contexts including Earth's magnetosphere, where the process can be investigated in situ by spacecraft. On 11 July 2017, the four Magnetospheric Multiscale spacecraft encountered a reconnection site in Earth's magnetotail, where reconnection involves symmetric inflow conditions. The electron-scale plasma measurements revealed (i) super-Alfvénic electron jets reaching 15,000 kilometers per second; (ii) electron meandering motion and acceleration by the electric field, producing multiple crescent-shaped structures in the velocity distributions; and (iii) the spatial dimensions of the electron diffusion region with an aspect ratio of 0.1 to 0.2, consistent with fast reconnection. The well-structured multiple layers of electron populations indicate that the dominant electron dynamics are mostly laminar, despite the presence of turbulence near the reconnection site.
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Affiliation(s)
- R B Torbert
- University of New Hampshire, Durham, NH, USA. .,Southwest Research Institute (SwRI), San Antonio, TX, USA
| | - J L Burch
- Southwest Research Institute (SwRI), San Antonio, TX, USA
| | - T D Phan
- University of California, Berkeley, CA, USA
| | - M Hesse
- Southwest Research Institute (SwRI), San Antonio, TX, USA.,University of Bergen, Bergen, Norway
| | - M R Argall
- University of New Hampshire, Durham, NH, USA
| | - J Shuster
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - R E Ergun
- University of Colorado Laboratory for Atmospheric and Space Physics, Boulder, CO, USA
| | - L Alm
- Swedish Institute of Space Physics, Uppsala, Sweden
| | - R Nakamura
- Space Research Institute, Austrian Academy of Sciences, Graz, Austria
| | - K J Genestreti
- Space Research Institute, Austrian Academy of Sciences, Graz, Austria
| | - D J Gershman
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - W R Paterson
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - D L Turner
- Aerospace Corporation, El Segundo, CA, USA
| | - I Cohen
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - B L Giles
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - C J Pollock
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - S Wang
- University of Maryland, College Park, MD, USA
| | - L-J Chen
- NASA Goddard Space Flight Center, Greenbelt, MD, USA.,University of Maryland, College Park, MD, USA
| | - J E Stawarz
- Blackett Laboratory, Imperial College London, London, UK
| | - J P Eastwood
- Blackett Laboratory, Imperial College London, London, UK
| | - K J Hwang
- Southwest Research Institute (SwRI), San Antonio, TX, USA
| | - C Farrugia
- University of New Hampshire, Durham, NH, USA
| | - I Dors
- University of New Hampshire, Durham, NH, USA
| | - H Vaith
- University of New Hampshire, Durham, NH, USA
| | - C Mouikis
- University of New Hampshire, Durham, NH, USA
| | - A Ardakani
- University of New Hampshire, Durham, NH, USA
| | - B H Mauk
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - S A Fuselier
- Southwest Research Institute (SwRI), San Antonio, TX, USA.,University of Texas, San Antonio, TX, USA
| | - C T Russell
- University of California, Los Angeles, CA, USA
| | | | - T E Moore
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - J F Drake
- University of Maryland, College Park, MD, USA
| | - M A Shay
- University of Delaware, Newark, DE, USA
| | | | | | - W Baumjohann
- Space Research Institute, Austrian Academy of Sciences, Graz, Austria
| | - F D Wilder
- University of Colorado Laboratory for Atmospheric and Space Physics, Boulder, CO, USA
| | - N Ahmadi
- University of Colorado Laboratory for Atmospheric and Space Physics, Boulder, CO, USA
| | - J C Dorelli
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - L A Avanov
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - M Oka
- University of California, Berkeley, CA, USA
| | - D N Baker
- University of Colorado Laboratory for Atmospheric and Space Physics, Boulder, CO, USA
| | | | - J B Blake
- Aerospace Corporation, El Segundo, CA, USA
| | | | - O Le Contel
- Laboratoire de Physique des Plasmas, CNRS/Ecole Polytechnique/Sorbonne Université/Univ. Paris Sud/Observatoire de Paris, Paris, France
| | - S M Petrinec
- Lockheed Martin Advanced Technology Center, Palo Alto, CA, USA
| | - B Lavraud
- Institut de Recherche en Astrophysique et Planétologie, CNRS, Centre National d'Etudes Spatiales, Université de Toulouse, Toulouse, France
| | - Y Saito
- Institute for Space and Astronautical Sciences, Sagamihara, Japan
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12
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Kollmann P, Roussos E, Paranicas C, Woodfield EE, Mauk BH, Clark G, Smith DC, Vandegriff J. Electron Acceleration to MeV Energies at Jupiter and Saturn. J Geophys Res Space Phys 2018; 123:9110-9129. [PMID: 30775196 PMCID: PMC6360449 DOI: 10.1029/2018ja025665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 08/16/2018] [Accepted: 09/24/2018] [Indexed: 06/09/2023]
Abstract
The radiation belts and magnetospheres of Jupiter and Saturn show significant intensities of relativistic electrons with energies up to tens of megaelectronvolts (MeV). To date, the question on how the electrons reach such high energies is not fully answered. This is largely due to the lack of high-quality electron spectra in the MeV energy range that models could be fit to. We reprocess data throughout the Galileo orbiter mission in order to derive Jupiter's electron spectra up to tens of MeV. In the case of Saturn, the spectra from the Cassini orbiter are readily available and we provide a systematic analysis aiming to study their acceleration mechanisms. Our analysis focuses on the magnetospheres of these planets, at distances of L > 20 and L > 4 for Jupiter and Saturn, respectively, where electron intensities are not yet at radiation belt levels. We find no support that MeV electrons are dominantly accelerated by wave-particle interactions in the magnetospheres of both planets at these distances. Instead, electron acceleration is consistent with adiabatic transport. While this is a common assumption, confirmation of this fact is important since many studies on sources, losses, and transport of energetic particles rely on it. Adiabatic heating can be driven through various radial transport mechanisms, for example, injections driven by the interchange instability or radial diffusion. We cannot distinguish these processes at Saturn with our technique. For Jupiter, we suggest that the dominating acceleration process is radial diffusion because injections are never observed at MeV energies.
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Affiliation(s)
- P. Kollmann
- The Johns Hopkins University, Applied Physics LaboratoryLaurelMDUSA
| | - E. Roussos
- Max Planck Institute for Solar System ResearchGóttingenGermany
| | - C. Paranicas
- The Johns Hopkins University, Applied Physics LaboratoryLaurelMDUSA
| | | | - B. H. Mauk
- The Johns Hopkins University, Applied Physics LaboratoryLaurelMDUSA
| | - G. Clark
- The Johns Hopkins University, Applied Physics LaboratoryLaurelMDUSA
| | - D. C. Smith
- The Johns Hopkins University, Applied Physics LaboratoryLaurelMDUSA
| | - J. Vandegriff
- The Johns Hopkins University, Applied Physics LaboratoryLaurelMDUSA
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13
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Roussos E, Kollmann P, Krupp N, Kotova A, Regoli L, Paranicas C, Mitchell DG, Krimigis SM, Hamilton D, Brandt P, Carbary J, Christon S, Dialynas K, Dandouras I, Hill ME, Ip WH, Jones GH, Livi S, Mauk BH, Palmaerts B, Roelof EC, Rymer A, Sergis N, Smith HT. A radiation belt of energetic protons located between Saturn and its rings. Science 2018; 362:362/6410/eaat1962. [DOI: 10.1126/science.aat1962] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2018] [Accepted: 09/05/2018] [Indexed: 11/03/2022]
Abstract
Saturn has a sufficiently strong dipole magnetic field to trap high-energy charged particles and form radiation belts, which have been observed outside its rings. Whether stable radiation belts exist near the planet and inward of the rings was previously unknown. The Cassini spacecraft’s Magnetosphere Imaging Instrument obtained measurements of a radiation belt that lies just above Saturn’s dense atmosphere and is decoupled from the rest of the magnetosphere by the planet’s A- to C-rings. The belt extends across the D-ring and comprises protons produced through cosmic ray albedo neutron decay and multiple charge-exchange reactions. These protons are lost to atmospheric neutrals and D-ring dust. Strong proton depletions that map onto features on the D-ring indicate a highly structured and diverse dust environment near Saturn.
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14
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Turner DL, Wilson LB, Liu TZ, Cohen IJ, Schwartz SJ, Osmane A, Fennell JF, Clemmons JH, Blake JB, Westlake J, Mauk BH, Jaynes AN, Leonard T, Baker DN, Strangeway RJ, Russell CT, Gershman DJ, Avanov L, Giles BL, Torbert RB, Broll J, Gomez RG, Fuselier SA, Burch JL. Autogenous and efficient acceleration of energetic ions upstream of Earth's bow shock. Nature 2018; 561:206-210. [PMID: 30209369 DOI: 10.1038/s41586-018-0472-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 07/06/2018] [Indexed: 11/09/2022]
Abstract
Earth and its magnetosphere are immersed in the supersonic flow of the solar-wind plasma that fills interplanetary space. As the solar wind slows and deflects to flow around Earth, or any other obstacle, a 'bow shock' forms within the flow. Under almost all solar-wind conditions, planetary bow shocks such as Earth's are collisionless, supercritical shocks, meaning that they reflect and accelerate a fraction of the incident solar-wind ions as an energy dissipation mechanism1,2, which results in the formation of a region called the ion foreshock3. In the foreshock, large-scale, transient phenomena can develop, such as 'hot flow anomalies'4-9, which are concentrations of shock-reflected, suprathermal ions that are channelled and accumulated along certain structures in the upstream magnetic field. Hot flow anomalies evolve explosively, often resulting in the formation of new shocks along their upstream edges5,10, and potentially contribute to particle acceleration11-13, but there have hitherto been no observations to constrain this acceleration or to confirm the underlying mechanism. Here we report observations of a hot flow anomaly accelerating solar-wind ions from roughly 1-10 kiloelectronvolts up to almost 1,000 kiloelectronvolts. The acceleration mechanism depends on the mass and charge state of the ions and is consistent with first-order Fermi acceleration14,15. The acceleration that we observe results from only the interaction of Earth's bow shock with the solar wind, but produces a much, much larger number of energetic particles compared to what would typically be produced in the foreshock from acceleration at the bow shock. Such autogenous and efficient acceleration at quasi-parallel bow shocks (the normal direction of which are within about 45 degrees of the interplanetary magnetic field direction) provides a potential solution to Fermi's 'injection problem', which requires an as-yet-unexplained seed population of energetic particles, and implies that foreshock transients may be important in the generation of cosmic rays at astrophysical shocks throughout the cosmos.
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Affiliation(s)
- D L Turner
- Space Sciences Department, The Aerospace Corporation, El Segundo, CA, USA.
| | - L B Wilson
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - T Z Liu
- Department of Earth, Planetary, and Space Science, University of California, Los Angeles, CA, USA
| | - I J Cohen
- Applied Physics Laboratory, Laurel, MD, USA
| | | | - A Osmane
- School of Electrical Engineering, Aalto University, Espoo, Finland.,Rudolf Peierls Centre of Theoretical Physics, University of Oxford, Oxford, UK
| | - J F Fennell
- Space Sciences Department, The Aerospace Corporation, El Segundo, CA, USA
| | - J H Clemmons
- Space Sciences Department, The Aerospace Corporation, El Segundo, CA, USA
| | - J B Blake
- Space Sciences Department, The Aerospace Corporation, El Segundo, CA, USA
| | - J Westlake
- Applied Physics Laboratory, Laurel, MD, USA
| | - B H Mauk
- Applied Physics Laboratory, Laurel, MD, USA
| | - A N Jaynes
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA, USA
| | - T Leonard
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO, USA
| | - D N Baker
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO, USA
| | - R J Strangeway
- Department of Earth, Planetary, and Space Science, University of California, Los Angeles, CA, USA
| | - C T Russell
- Department of Earth, Planetary, and Space Science, University of California, Los Angeles, CA, USA
| | - D J Gershman
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - L Avanov
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - B L Giles
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - R B Torbert
- Institute For the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH, USA.,Southwest Research Institute, San Antonio, TX, USA
| | - J Broll
- Southwest Research Institute, San Antonio, TX, USA.,Departoment of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX, USA
| | - R G Gomez
- Space Sciences Department, The Aerospace Corporation, El Segundo, CA, USA
| | - S A Fuselier
- Southwest Research Institute, San Antonio, TX, USA.,Departoment of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX, USA
| | - J L Burch
- Southwest Research Institute, San Antonio, TX, USA
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15
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Gladstone GR, Versteeg MH, Greathouse TK, Hue V, Davis MW, Gérard J, Grodent DC, Bonfond B, Nichols JD, Wilson RJ, Hospodarsky GB, Bolton SJ, Levin SM, Connerney JEP, Adriani A, Kurth WS, Mauk BH, Valek P, McComas DJ, Orton GS, Bagenal F. Juno-UVS approach observations of Jupiter's auroras. Geophys Res Lett 2017; 44:7668-7675. [PMID: 28989207 PMCID: PMC5606505 DOI: 10.1002/2017gl073377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 04/17/2017] [Accepted: 04/18/2017] [Indexed: 06/07/2023]
Abstract
Juno ultraviolet spectrograph (UVS) observations of Jupiter's aurora obtained during approach are presented. Prior to the bow shock crossing on 24 June 2016, the Juno approach provided a rare opportunity to correlate local solar wind conditions with Jovian auroral emissions. Some of Jupiter's auroral emissions are expected to be controlled or modified by local solar wind conditions. Here we compare synoptic Juno-UVS observations of Jupiter's auroral emissions, acquired during 3-29 June 2016, with in situ solar wind observations, and related Jupiter observations from Earth. Four large auroral brightening events are evident in the synoptic data, in which the total emitted auroral power increases by a factor of 3-4 for a few hours. Only one of these brightening events correlates well with large transient increases in solar wind ram pressure. The brightening events which are not associated with the solar wind generally have a risetime of ~2 h and a decay time of ~5 h.
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Affiliation(s)
- G. R. Gladstone
- Southwest Research InstituteSan AntonioTexasUSA
- Department of Physics and AstronomyUniversity of Texas at San AntonioSan AntonioTexasUSA
| | | | | | - V. Hue
- Southwest Research InstituteSan AntonioTexasUSA
| | - M. W. Davis
- Southwest Research InstituteSan AntonioTexasUSA
| | - J.‐C. Gérard
- STAR Institute, LPAPUniversité de LiègeLiègeBelgium
| | | | - B. Bonfond
- STAR Institute, LPAPUniversité de LiègeLiègeBelgium
| | - J. D. Nichols
- Department of Physics and AstronomyUniversity of LeicesterLeicesterUK
| | - R. J. Wilson
- Laboratory for Atmospheric and Space PhysicsUniversity of Colorado BoulderBoulderColoradoUSA
| | - G. B. Hospodarsky
- Department of Physics and AstronomyUniversity of IowaIowa CityIowaUSA
| | | | - S. M. Levin
- Jet Propulsion LaboratoryPasadenaCaliforniaUSA
| | | | - A. Adriani
- Istituto di Astrofisica e Planetologia SpazialiRomeItaly
| | - W. S. Kurth
- Department of Physics and AstronomyUniversity of IowaIowa CityIowaUSA
| | - B. H. Mauk
- The Johns Hopkins University Applied Physics LaboratoryLaurelMarylandUSA
| | - P. Valek
- Southwest Research InstituteSan AntonioTexasUSA
| | - D. J. McComas
- Office of the VP for PPPL and Department of Astrophysical SciencesPrinceton UniversityPrincetonNew JerseyUSA
| | - G. S. Orton
- Jet Propulsion LaboratoryPasadenaCaliforniaUSA
| | - F. Bagenal
- Laboratory for Atmospheric and Space PhysicsUniversity of Colorado BoulderBoulderColoradoUSA
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16
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Clark G, Cohen I, Westlake JH, Andrews GB, Brandt P, Gold RE, Gkioulidou MA, Hacala R, Haggerty D, Hill ME, Ho GC, Jaskulek SE, Kollmann P, Mauk BH, McNutt RL, Mitchell DG, Nelson KS, Paranicas C, Paschalidis N, Schlemm CE. The "Puck" energetic charged particle detector: Design, heritage, and advancements. J Geophys Res Space Phys 2016; 121:7900-7913. [PMID: 27867799 PMCID: PMC5101846 DOI: 10.1002/2016ja022579] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Revised: 06/10/2016] [Accepted: 07/27/2016] [Indexed: 06/06/2023]
Abstract
Energetic charged particle detectors characterize a portion of the plasma distribution function that plays critical roles in some physical processes, from carrying the currents in planetary ring currents to weathering the surfaces of planetary objects. For several low-resource missions in the past, the need was recognized for a low-resource but highly capable, mass-species-discriminating energetic particle sensor that could also obtain angular distributions without motors or mechanical articulation. This need led to the development of a compact Energetic Particle Detector (EPD), known as the "Puck" EPD (short for hockey puck), that is capable of determining the flux, angular distribution, and composition of incident ions between an energy range of ~10 keV to several MeV. This sensor makes simultaneous angular measurements of electron fluxes from the tens of keV to about 1 MeV. The same measurements can be extended down to approximately 1 keV/nucleon, with some composition ambiguity. These sensors have a proven flight heritage record that includes missions such as MErcury Surface, Space ENvironment, GEochemistry, and Ranging and New Horizons, with multiple sensors on each of Juno, Van Allen Probes, and Magnetospheric Multiscale. In this review paper we discuss the Puck EPD design, its heritage, unexpected results from these past missions and future advancements. We also discuss high-voltage anomalies that are thought to be associated with the use of curved foils, which is a new foil manufacturing processes utilized on recent Puck EPD designs. Finally, we discuss the important role Puck EPDs can potentially play in upcoming missions.
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Affiliation(s)
- G. Clark
- The Johns Hopkins University Applied Physics LaboratoryLaurelMarylandUSA
| | - I. Cohen
- The Johns Hopkins University Applied Physics LaboratoryLaurelMarylandUSA
| | - J. H. Westlake
- The Johns Hopkins University Applied Physics LaboratoryLaurelMarylandUSA
| | - G. B. Andrews
- The Johns Hopkins University Applied Physics LaboratoryLaurelMarylandUSA
| | - P. Brandt
- The Johns Hopkins University Applied Physics LaboratoryLaurelMarylandUSA
| | - R. E. Gold
- The Johns Hopkins University Applied Physics LaboratoryLaurelMarylandUSA
| | - M. A. Gkioulidou
- The Johns Hopkins University Applied Physics LaboratoryLaurelMarylandUSA
| | - R. Hacala
- The Johns Hopkins University Applied Physics LaboratoryLaurelMarylandUSA
| | - D. Haggerty
- The Johns Hopkins University Applied Physics LaboratoryLaurelMarylandUSA
| | - M. E. Hill
- The Johns Hopkins University Applied Physics LaboratoryLaurelMarylandUSA
| | - G. C. Ho
- The Johns Hopkins University Applied Physics LaboratoryLaurelMarylandUSA
| | - S. E. Jaskulek
- The Johns Hopkins University Applied Physics LaboratoryLaurelMarylandUSA
| | - P. Kollmann
- The Johns Hopkins University Applied Physics LaboratoryLaurelMarylandUSA
| | - B. H. Mauk
- The Johns Hopkins University Applied Physics LaboratoryLaurelMarylandUSA
| | - R. L. McNutt
- The Johns Hopkins University Applied Physics LaboratoryLaurelMarylandUSA
| | - D. G. Mitchell
- The Johns Hopkins University Applied Physics LaboratoryLaurelMarylandUSA
| | - K. S. Nelson
- The Johns Hopkins University Applied Physics LaboratoryLaurelMarylandUSA
| | - C. Paranicas
- The Johns Hopkins University Applied Physics LaboratoryLaurelMarylandUSA
| | | | - C. E. Schlemm
- The Johns Hopkins University Applied Physics LaboratoryLaurelMarylandUSA
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17
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Nakamura R, Sergeev VA, Baumjohann W, Plaschke F, Magnes W, Fischer D, Varsani A, Schmid D, Nakamura TKM, Russell CT, Strangeway RJ, Leinweber HK, Le G, Bromund KR, Pollock CJ, Giles BL, Dorelli JC, Gershman DJ, Paterson W, Avanov LA, Fuselier SA, Genestreti K, Burch JL, Torbert RB, Chutter M, Argall MR, Anderson BJ, Lindqvist P, Marklund GT, Khotyaintsev YV, Mauk BH, Cohen IJ, Baker DN, Jaynes AN, Ergun RE, Singer HJ, Slavin JA, Kepko EL, Moore TE, Lavraud B, Coffey V, Saito Y. Transient, small-scale field-aligned currents in the plasma sheet boundary layer during storm time substorms. Geophys Res Lett 2016; 43:4841-4849. [PMID: 27867235 PMCID: PMC5111425 DOI: 10.1002/2016gl068768] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 04/26/2016] [Accepted: 05/03/2016] [Indexed: 06/02/2023]
Abstract
We report on field-aligned current observations by the four Magnetospheric Multiscale (MMS) spacecraft near the plasma sheet boundary layer (PSBL) during two major substorms on 23 June 2015. Small-scale field-aligned currents were found embedded in fluctuating PSBL flux tubes near the separatrix region. We resolve, for the first time, short-lived earthward (downward) intense field-aligned current sheets with thicknesses of a few tens of kilometers, which are well below the ion scale, on flux tubes moving equatorward/earthward during outward plasma sheet expansion. They coincide with upward field-aligned electron beams with energies of a few hundred eV. These electrons are most likely due to acceleration associated with a reconnection jet or high-energy ion beam-produced disturbances. The observations highlight coupling of multiscale processes in PSBL as a consequence of magnetotail reconnection.
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Burch JL, Torbert RB, Phan TD, Chen LJ, Moore TE, Ergun RE, Eastwood JP, Gershman DJ, Cassak PA, Argall MR, Wang S, Hesse M, Pollock CJ, Giles BL, Nakamura R, Mauk BH, Fuselier SA, Russell CT, Strangeway RJ, Drake JF, Shay MA, Khotyaintsev YV, Lindqvist PA, Marklund G, Wilder FD, Young DT, Torkar K, Goldstein J, Dorelli JC, Avanov LA, Oka M, Baker DN, Jaynes AN, Goodrich KA, Cohen IJ, Turner DL, Fennell JF, Blake JB, Clemmons J, Goldman M, Newman D, Petrinec SM, Trattner KJ, Lavraud B, Reiff PH, Baumjohann W, Magnes W, Steller M, Lewis W, Saito Y, Coffey V, Chandler M. Electron-scale measurements of magnetic reconnection in space. Science 2016; 352:aaf2939. [PMID: 27174677 DOI: 10.1126/science.aaf2939] [Citation(s) in RCA: 438] [Impact Index Per Article: 54.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 05/03/2016] [Indexed: 11/02/2022]
Abstract
Magnetic reconnection is a fundamental physical process in plasmas whereby stored magnetic energy is converted into heat and kinetic energy of charged particles. Reconnection occurs in many astrophysical plasma environments and in laboratory plasmas. Using measurements with very high time resolution, NASA's Magnetospheric Multiscale (MMS) mission has found direct evidence for electron demagnetization and acceleration at sites along the sunward boundary of Earth's magnetosphere where the interplanetary magnetic field reconnects with the terrestrial magnetic field. We have (i) observed the conversion of magnetic energy to particle energy; (ii) measured the electric field and current, which together cause the dissipation of magnetic energy; and (iii) identified the electron population that carries the current as a result of demagnetization and acceleration within the reconnection diffusion/dissipation region.
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Affiliation(s)
- J L Burch
- Southwest Research Institute, San Antonio, TX, USA.
| | - R B Torbert
- Southwest Research Institute, San Antonio, TX, USA. University of New Hampshire, Durham, NH, USA
| | - T D Phan
- University of California, Berkeley, CA, USA
| | - L-J Chen
- University of Maryland, College Park, MD, USA
| | - T E Moore
- NASA, Goddard Space Flight Center, Greenbelt, MD, USA
| | - R E Ergun
- University of Colorado LASP, Boulder, CO, USA
| | - J P Eastwood
- Blackett Laboratory, Imperial College London, London, UK
| | - D J Gershman
- NASA, Goddard Space Flight Center, Greenbelt, MD, USA
| | - P A Cassak
- West Virginia University, Morgantown, WV, USA
| | - M R Argall
- University of New Hampshire, Durham, NH, USA
| | - S Wang
- University of Maryland, College Park, MD, USA
| | - M Hesse
- NASA, Goddard Space Flight Center, Greenbelt, MD, USA
| | - C J Pollock
- NASA, Goddard Space Flight Center, Greenbelt, MD, USA
| | - B L Giles
- NASA, Goddard Space Flight Center, Greenbelt, MD, USA
| | - R Nakamura
- Space Research Institute, Austrian Academy of Sciences, Graz, Austria
| | - B H Mauk
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - S A Fuselier
- Southwest Research Institute, San Antonio, TX, USA
| | - C T Russell
- University of California, Los Angeles, CA, USA
| | | | - J F Drake
- University of Maryland, College Park, MD, USA
| | - M A Shay
- University of Delaware, Newark, DE, USA
| | | | | | - G Marklund
- Royal Institute of Technology, Stockholm, Sweden
| | - F D Wilder
- University of Colorado LASP, Boulder, CO, USA
| | - D T Young
- Southwest Research Institute, San Antonio, TX, USA
| | - K Torkar
- Space Research Institute, Austrian Academy of Sciences, Graz, Austria
| | - J Goldstein
- Southwest Research Institute, San Antonio, TX, USA
| | - J C Dorelli
- NASA, Goddard Space Flight Center, Greenbelt, MD, USA
| | - L A Avanov
- NASA, Goddard Space Flight Center, Greenbelt, MD, USA
| | - M Oka
- University of California, Berkeley, CA, USA
| | - D N Baker
- University of Colorado LASP, Boulder, CO, USA
| | - A N Jaynes
- University of Colorado LASP, Boulder, CO, USA
| | | | - I J Cohen
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - D L Turner
- Aerospace Corporation, El Segundo, CA, USA
| | | | - J B Blake
- Aerospace Corporation, El Segundo, CA, USA
| | - J Clemmons
- Aerospace Corporation, El Segundo, CA, USA
| | - M Goldman
- University of Colorado, Boulder, CO, USA
| | - D Newman
- University of Colorado, Boulder, CO, USA
| | - S M Petrinec
- Lockheed Martin Advanced Technology Center, Palo Alto, CA, USA
| | | | - B Lavraud
- Institut de Recherche en Astrophysique et Planétologie, Toulouse, France
| | - P H Reiff
- Department of Physics and Astronomy, Rice University, Houston, TX, USA
| | - W Baumjohann
- Space Research Institute, Austrian Academy of Sciences, Graz, Austria
| | - W Magnes
- Space Research Institute, Austrian Academy of Sciences, Graz, Austria
| | - M Steller
- Space Research Institute, Austrian Academy of Sciences, Graz, Austria
| | - W Lewis
- Southwest Research Institute, San Antonio, TX, USA
| | - Y Saito
- Institute for Space and Astronautical Sciences, Sagamihara, Japan
| | - V Coffey
- NASA, Marshall Space Flight Center, Huntsville, AL, USA
| | - M Chandler
- NASA, Marshall Space Flight Center, Huntsville, AL, USA
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Mauk BH. Comparative investigation of the energetic ion spectra comprising the magnetospheric ring currents of the solar system. J Geophys Res Space Phys 2014; 119:9729-9746. [PMID: 26167438 PMCID: PMC4497457 DOI: 10.1002/2014ja020392] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 11/08/2014] [Indexed: 05/29/2023]
Abstract
Investigated here are factors that control the intensities and shapes of energetic ion spectra that make up the ring current populations of the strongly magnetized planets of the solar system, specifically those of Earth, Jupiter, Saturn, Uranus, and Neptune. Following a previous and similar comparative investigation of radiation belt electrons, we here turn our attention to ions. Specifically, we examine the possible role of the differential ion Kennel-Petschek limit, as moderated by Electromagnetic Ion Cyclotron (EMIC) waves, as a standard for comparing the most intense ion spectra within the strongly magnetized planetary magnetospheres. In carrying out this investigation, the substantial complexities engendered by the very different ion composition distributions of these diverse magnetospheres must be addressed, given that the dispersion properties of the EMIC waves are strongly determined by the ion composition of the plasmas within which the waves propagate. Chosen for comparison are the ion spectra within these systems that are the most intense observed, specifically at 100 keV and 1 MeV. We find that Earth and Jupiter are unique in having their most intense ion spectra likely limited and sculpted by the Kennel-Petschek process. The ion spectra of Saturn, Uranus, and Neptune reside far below their respective limits and are likely limited by interactions with gas and dust (Saturn) and by the absence of robust ion acceleration processes (Uranus and Neptune). Suggestions are provided for further testing the efficacy of the differential Kennel-Petschek limit for ions using the Van Allen Probes.
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Affiliation(s)
- B H Mauk
- Johns Hopkins University Applied Physics LaboratoryLaurel, Maryland, USA
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Ukhorskiy AY, Sitnov MI, Mitchell DG, Takahashi K, Lanzerotti LJ, Mauk BH. Rotationally driven ‘zebra stripes’ in Earth’s inner radiation belt. Nature 2014; 507:338-40. [DOI: 10.1038/nature13046] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 01/16/2014] [Indexed: 11/09/2022]
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Sánchez ER, Mauk BH, Newell PT, Meng CI. Low-altitude observations of the evolution of substorm injection boundaries. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/92ja01692] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Mauk BH, Krimigis SM, Keath EP, Cheng AF, Armstrong TP, Lanzerotti LJ, Gloeckler G, Hamilton DC. The hot plasma and radiation environment of the Uranian magnetosphere. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/ja092ia13p15283] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Cheng AF, Krimigis SM, Mauk BH, Keath EP, Maclennan CG, Lanzerotti LJ, Paonessa MT, Armstrong TP. Energetic ion and electron phase space densities in the magnetosphere of Uranus. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/ja092ia13p15315] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Gurgiolo C, Parks GK, Mauk BH, Lin CS, Anderson KA, Lin RP, Reme H. Non-E × Bordered ion beams upstream of the Earth's bow shock. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/ja086ia06p04415] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Affiliation(s)
- B. H. Mauk
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
| | - N. J. Fox
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
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Müller AL, Saur J, Krupp N, Roussos E, Mauk BH, Rymer AM, Mitchell DG, Krimigis SM. Azimuthal plasma flow in the Kronian magnetosphere. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009ja015122] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- A. L. Müller
- Max Planck Institute for Solar System Research; Katlenburg-Lindau Germany
- Institute of Geophysics and Meteorology; University of Cologne; Cologne Germany
| | - J. Saur
- Institute of Geophysics and Meteorology; University of Cologne; Cologne Germany
| | - N. Krupp
- Max Planck Institute for Solar System Research; Katlenburg-Lindau Germany
| | - E. Roussos
- Max Planck Institute for Solar System Research; Katlenburg-Lindau Germany
| | - B. H. Mauk
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
| | - A. M. Rymer
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
| | - D. G. Mitchell
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
| | - S. M. Krimigis
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
- Office of Space Research Technology; Academy of Athens; Athens Greece
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Krimigis SM, Armstrong TP, Axford WI, Cheng AF, Gloeckler G, Hamilton DC, Keath EP, Lanzerotti LJ, Mauk BH. The magnetosphere of uranus: hot plasma and radiation environment. Science 2010; 233:97-102. [PMID: 17812897 DOI: 10.1126/science.233.4759.97] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The low-energy charged-particle (LECP) instrument on Voyager 2 measured lowenergy electrons and ions near and within the magnetosphere of Uranus. Initial analysis of the LECP measurements has revealed the following. (i) The magnetospheric particle population consists principally of protons and electrons having energies to at least 4 and 1.2 megaelectron volts, respectively, with electron intensities substantially excceding proton intensities at a given energy. (ii) The intensity profile for both particle species shows evidence that the particles were swept by planetry satellites out to at least the orbit of Titania. (iii) The ion and electron spectra may be described by a Maxwellian core at low energies (less than about 200 kiloelectron volts) and a power law at high energies (greater than about 590 kiloelectron volts; exponentmicro, 3 to 10) except inside the orbit of Miranda, where power-law spectra (micro approximately 1.1 and 3.1 for electrons and protons, respectively) are observed. (iv) At ion energies between 0.6 and 1 megaelectron volt per nucleon, the composition is dominated by protons with a minor fraction (about 10(-3)) of molecular hydrogen; the lower limit for the ratio of hydrogen to helium is greater than 10(4). (v) The proton population is sufficiently intense that fluences greater than 10(16) per square centimeter can accumulate in 10(4) to 10(') years; such fluences are sufficient to polymerize carbon monoxide and methane ice surfaces. The overall morphology of Uranus' magnetosphere resembles that of Jupiter, as evidenced by the fact that the spacecraft crossed the plasma sheet through the dawn magnetosheath twice per planetary rotation period (17.3 hours). Uranus' magnetosphere differs from that of Jupiter and of Saturn in that the plasma 1 is at most 0.1 rather than 1. Therefore, little distortion ofthe field is expected from particle loading at distances less than about 15 Uranus radii.
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Sergis N, Krimigis SM, Mitchell DG, Hamilton DC, Krupp N, Mauk BH, Roelof EC, Dougherty MK. Energetic particle pressure in Saturn's magnetosphere measured with the Magnetospheric Imaging Instrument on Cassini. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008ja013774] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- N. Sergis
- Office for Space Research and Technology; Academy of Athens; Athens Greece
| | - S. M. Krimigis
- Office for Space Research and Technology; Academy of Athens; Athens Greece
- Applied Physics Laboratory; Johns Hopkins University; Laurel Maryland USA
| | - D. G. Mitchell
- Applied Physics Laboratory; Johns Hopkins University; Laurel Maryland USA
| | - D. C. Hamilton
- Department of Physics; University of Maryland; College Park Maryland USA
| | - N. Krupp
- Max-Planck-Institut für Sonnensystemforschung; Lindau Germany
| | - B. H. Mauk
- Applied Physics Laboratory; Johns Hopkins University; Laurel Maryland USA
| | - E. C. Roelof
- Applied Physics Laboratory; Johns Hopkins University; Laurel Maryland USA
| | - M. K. Dougherty
- Space and Atmospheric Physics Group; Imperial College; London UK
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Mitchell DG, Kurth WS, Hospodarsky GB, Krupp N, Saur J, Mauk BH, Carbary JF, Krimigis SM, Dougherty MK, Hamilton DC. Ion conics and electron beams associated with auroral processes on Saturn. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008ja013621] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- D. G. Mitchell
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
| | - W. S. Kurth
- Department of Physics and Astronomy; University of Iowa; Iowa City Iowa USA
| | - G. B. Hospodarsky
- Department of Physics and Astronomy; University of Iowa; Iowa City Iowa USA
| | - N. Krupp
- Max-Planck-Institut für Sonnensystemforschung; Katlenburg-Lindau Germany
| | - J. Saur
- Institut für Geophysik and Meteorologie; Universität zu Köln; Cologne Germany
| | - B. H. Mauk
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
| | - J. F. Carbary
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
| | - S. M. Krimigis
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
| | | | - D. C. Hamilton
- Department of Astronomy; University of Maryland; College Park Maryland USA
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Affiliation(s)
- A. M. Rymer
- Johns Hopkins University, Applied Physics Laboratory; USA
| | - B. H. Mauk
- Johns Hopkins University, Applied Physics Laboratory; USA
| | - T. W. Hill
- Department of Physics and Astronomy; Rice University; USA
| | - C. Paranicas
- Johns Hopkins University, Applied Physics Laboratory; USA
| | - D. G. Mitchell
- Johns Hopkins University, Applied Physics Laboratory; USA
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McNutt RL, Haggerty DK, Hill ME, Krimigis SM, Livi S, Ho GC, Gurnee RS, Mauk BH, Mitchell DG, Roelof EC, McComas DJ, Bagenal F, Elliott HA, Brown LE, Kusterer M, Vandegriff J, Stern SA, Weaver HA, Spencer JR, Moore JM. Energetic Particles in the Jovian Magnetotail. Science 2007; 318:220-2. [PMID: 17932283 DOI: 10.1126/science.1148025] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- R. L. McNutt
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723, USA
- Academy of Athens, 28 Panapistimiou, 10679 Athens, Greece
- Southwest Research Institute, San Antonio, TX 78228, USA
- Laboratory of Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309–0392, USA
- NASA Headquarters, Washington, DC 20546–0001, USA
| | - D. K. Haggerty
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723, USA
- Academy of Athens, 28 Panapistimiou, 10679 Athens, Greece
- Southwest Research Institute, San Antonio, TX 78228, USA
- Laboratory of Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309–0392, USA
- NASA Headquarters, Washington, DC 20546–0001, USA
| | - M. E. Hill
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723, USA
- Academy of Athens, 28 Panapistimiou, 10679 Athens, Greece
- Southwest Research Institute, San Antonio, TX 78228, USA
- Laboratory of Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309–0392, USA
- NASA Headquarters, Washington, DC 20546–0001, USA
| | - S. M. Krimigis
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723, USA
- Academy of Athens, 28 Panapistimiou, 10679 Athens, Greece
- Southwest Research Institute, San Antonio, TX 78228, USA
- Laboratory of Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309–0392, USA
- NASA Headquarters, Washington, DC 20546–0001, USA
| | - S. Livi
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723, USA
- Academy of Athens, 28 Panapistimiou, 10679 Athens, Greece
- Southwest Research Institute, San Antonio, TX 78228, USA
- Laboratory of Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309–0392, USA
- NASA Headquarters, Washington, DC 20546–0001, USA
| | - G. C. Ho
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723, USA
- Academy of Athens, 28 Panapistimiou, 10679 Athens, Greece
- Southwest Research Institute, San Antonio, TX 78228, USA
- Laboratory of Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309–0392, USA
- NASA Headquarters, Washington, DC 20546–0001, USA
| | - R. S. Gurnee
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723, USA
- Academy of Athens, 28 Panapistimiou, 10679 Athens, Greece
- Southwest Research Institute, San Antonio, TX 78228, USA
- Laboratory of Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309–0392, USA
- NASA Headquarters, Washington, DC 20546–0001, USA
| | - B. H. Mauk
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723, USA
- Academy of Athens, 28 Panapistimiou, 10679 Athens, Greece
- Southwest Research Institute, San Antonio, TX 78228, USA
- Laboratory of Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309–0392, USA
- NASA Headquarters, Washington, DC 20546–0001, USA
| | - D. G. Mitchell
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723, USA
- Academy of Athens, 28 Panapistimiou, 10679 Athens, Greece
- Southwest Research Institute, San Antonio, TX 78228, USA
- Laboratory of Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309–0392, USA
- NASA Headquarters, Washington, DC 20546–0001, USA
| | - E. C. Roelof
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723, USA
- Academy of Athens, 28 Panapistimiou, 10679 Athens, Greece
- Southwest Research Institute, San Antonio, TX 78228, USA
- Laboratory of Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309–0392, USA
- NASA Headquarters, Washington, DC 20546–0001, USA
| | - D. J. McComas
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723, USA
- Academy of Athens, 28 Panapistimiou, 10679 Athens, Greece
- Southwest Research Institute, San Antonio, TX 78228, USA
- Laboratory of Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309–0392, USA
- NASA Headquarters, Washington, DC 20546–0001, USA
| | - F. Bagenal
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723, USA
- Academy of Athens, 28 Panapistimiou, 10679 Athens, Greece
- Southwest Research Institute, San Antonio, TX 78228, USA
- Laboratory of Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309–0392, USA
- NASA Headquarters, Washington, DC 20546–0001, USA
| | - H. A. Elliott
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723, USA
- Academy of Athens, 28 Panapistimiou, 10679 Athens, Greece
- Southwest Research Institute, San Antonio, TX 78228, USA
- Laboratory of Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309–0392, USA
- NASA Headquarters, Washington, DC 20546–0001, USA
| | - L. E. Brown
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723, USA
- Academy of Athens, 28 Panapistimiou, 10679 Athens, Greece
- Southwest Research Institute, San Antonio, TX 78228, USA
- Laboratory of Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309–0392, USA
- NASA Headquarters, Washington, DC 20546–0001, USA
| | - M. Kusterer
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723, USA
- Academy of Athens, 28 Panapistimiou, 10679 Athens, Greece
- Southwest Research Institute, San Antonio, TX 78228, USA
- Laboratory of Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309–0392, USA
- NASA Headquarters, Washington, DC 20546–0001, USA
| | - J. Vandegriff
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723, USA
- Academy of Athens, 28 Panapistimiou, 10679 Athens, Greece
- Southwest Research Institute, San Antonio, TX 78228, USA
- Laboratory of Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309–0392, USA
- NASA Headquarters, Washington, DC 20546–0001, USA
| | - S. A. Stern
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723, USA
- Academy of Athens, 28 Panapistimiou, 10679 Athens, Greece
- Southwest Research Institute, San Antonio, TX 78228, USA
- Laboratory of Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309–0392, USA
- NASA Headquarters, Washington, DC 20546–0001, USA
| | - H. A. Weaver
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723, USA
- Academy of Athens, 28 Panapistimiou, 10679 Athens, Greece
- Southwest Research Institute, San Antonio, TX 78228, USA
- Laboratory of Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309–0392, USA
- NASA Headquarters, Washington, DC 20546–0001, USA
| | - J. R. Spencer
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723, USA
- Academy of Athens, 28 Panapistimiou, 10679 Athens, Greece
- Southwest Research Institute, San Antonio, TX 78228, USA
- Laboratory of Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309–0392, USA
- NASA Headquarters, Washington, DC 20546–0001, USA
| | - J. M. Moore
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723, USA
- Academy of Athens, 28 Panapistimiou, 10679 Athens, Greece
- Southwest Research Institute, San Antonio, TX 78228, USA
- Laboratory of Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309–0392, USA
- NASA Headquarters, Washington, DC 20546–0001, USA
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Rymer AM, Mauk BH, Hill TW, Paranicas C, André N, Sittler EC, Mitchell DG, Smith HT, Johnson RE, Coates AJ, Young DT, Bolton SJ, Thomsen MF, Dougherty MK. Electron sources in Saturn's magnetosphere. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006ja012017] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- A. M. Rymer
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
| | - B. H. Mauk
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
| | - T. W. Hill
- Department of Physics and Astronomy; Rice University; Houston Texas USA
| | - C. Paranicas
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
| | - N. André
- Research and Scientific Support Department; European Space Agency; Noordwijk Netherlands
| | - E. C. Sittler
- NASA Goddard Space Flight Center; Greenbelt Maryland USA
| | - D. G. Mitchell
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
| | - H. T. Smith
- University of Virginia; Charlottesville Virginia USA
| | - R. E. Johnson
- University of Virginia; Charlottesville Virginia USA
| | - A. J. Coates
- Mullard Space Science Laboratory; University College London; London UK
| | - D. T. Young
- Southwest Research Institute; San Antonio Texas USA
| | - S. J. Bolton
- Southwest Research Institute; San Antonio Texas USA
| | - M. F. Thomsen
- Space and Atmospheric Science Group; Los Alamos National Laboratory; Los Alamos New Mexico USA
| | - M. K. Dougherty
- Department of Space and Atmospheric Physics; Imperial College London; London UK
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Sittler EC, Johnson RE, Smith HT, Richardson JD, Jurac S, Moore M, Cooper JF, Mauk BH, Michael M, Paranicas C, Armstrong TP, Tsurutani B. Energetic nitrogen ions within the inner magnetosphere of Saturn. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2004ja010509] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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37
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Mitchell DG, Brandt PC, Roelof EC, Dandouras J, Krimigis SM, Mauk BH. Energetic Neutral Atom Emissions from Titan Interaction with Saturn's Magnetosphere. Science 2005; 308:989-92. [PMID: 15890874 DOI: 10.1126/science.1109805] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The Cassini Magnetospheric Imaging Instrument (MIMI) observed the interaction of Saturn's largest moon, Titan, with Saturn's magnetosphere during two close flybys of Titan on 26 October and 13 December 2004. The MIMI Ion and Neutral Camera (INCA) continuously imaged the energetic neutral atoms (ENAs) generated by charge exchange reactions between the energetic, singly ionized trapped magnetospheric ions and the outer atmosphere, or exosphere, of Titan. The images reveal a halo of variable ENA emission about Titan's nearly collisionless outer atmosphere that fades at larger distances as the exospheric density decays exponentially. The altitude of the emissions varies, and they are not symmetrical about the moon, reflecting the complexity of the interactions between Titan's upper atmosphere and Saturn's space environment.
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Affiliation(s)
- D G Mitchell
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 21042, USA.
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38
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Hori T, Lui ATY, Ohtani S, Cson Brandt P, Mauk BH, McEntire RW, Maezawa K, Mukai T, Kasaba Y, Hayakawa H. Storm-time convection electric field in the near-Earth plasma sheet. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2004ja010449] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- T. Hori
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
| | - A. T. Y. Lui
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
| | - S. Ohtani
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
| | - P. Cson Brandt
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
| | - B. H. Mauk
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
| | - R. W. McEntire
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
| | - K. Maezawa
- Institute of Space and Astronautical Science; Sagamihara Japan
| | - T. Mukai
- Institute of Space and Astronautical Science; Sagamihara Japan
| | - Y. Kasaba
- Institute of Space and Astronautical Science; Sagamihara Japan
| | - H. Hayakawa
- Institute of Space and Astronautical Science; Sagamihara Japan
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39
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Krimigis SM, Mitchell DG, Hamilton DC, Krupp N, Livi S, Roelof EC, Dandouras J, Armstrong TP, Mauk BH, Paranicas C, Brandt PC, Bolton S, Cheng AF, Choo T, Gloeckler G, Hayes J, Hsieh KC, Ip WH, Jaskulek S, Keath EP, Kirsch E, Kusterer M, Lagg A, Lanzerotti LJ, Lavallee D, Manweiler J, McEntire RW, Rasmuss W, Saur J, Turner FS, Williams DJ, Woch J. Dynamics of Saturn's Magnetosphere from MIMI During Cassini's Orbital Insertion. Science 2005; 307:1270-3. [PMID: 15731445 DOI: 10.1126/science.1105978] [Citation(s) in RCA: 149] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The Magnetospheric Imaging Instrument (MIMI) onboard the Cassini spacecraft observed the saturnian magnetosphere from January 2004 until Saturn orbit insertion (SOI) on 1 July 2004. The MIMI sensors observed frequent energetic particle activity in interplanetary space for several months before SOI. When the imaging sensor was switched to its energetic neutral atom (ENA) operating mode on 20 February 2004, at approximately 10(3) times Saturn's radius RS (0.43 astronomical units), a weak but persistent signal was observed from the magnetosphere. About 10 days before SOI, the magnetosphere exhibited a day-night asymmetry that varied with an approximately 11-hour periodicity. Once Cassini entered the magnetosphere, in situ measurements showed high concentrations of H+, H2+, O+, OH+, and H2O+ and low concentrations of N+. The radial dependence of ion intensity profiles implies neutral gas densities sufficient to produce high loss rates of trapped ions from the middle and inner magnetosphere. ENA imaging has revealed a radiation belt that resides inward of the D ring and is probably the result of double charge exchange between the main radiation belt and the upper layers of Saturn's exosphere.
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Affiliation(s)
- S M Krimigis
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723, USA.
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40
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41
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Mauk BH, Mitchell DG, Krimigis SM, Roelof EC, Paranicas CP. Energetic neutral atoms from a trans-Europa gas torus at Jupiter. Nature 2003; 421:920-2. [PMID: 12606993 DOI: 10.1038/nature01431] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2002] [Accepted: 01/13/2003] [Indexed: 11/09/2022]
Abstract
The space environments--or magnetospheres--of magnetized planets emit copious quantities of energetic neutral atoms (ENAs) at energies between tens of electron volts to hundreds of kiloelectron volts (keV). These energetic atoms result from charge exchange between magnetically trapped energetic ions and cold neutral atoms, and they carry significant amounts of energy and mass from the magnetospheres. Imaging their distribution allows us to investigate the structure of planetary magnetospheres. Here we report the analysis of 50-80 keV ENA images of Jupiter's magnetosphere, where two distinct emission regions dominate: the upper atmosphere of Jupiter itself, and a torus of emission residing just outside the orbit of Jupiter's satellite Europa. The trans-Europa component shows that, unexpectedly, Europa generates a gas cloud comparable in gas content to that associated with the volcanic moon Io. The quantity of gas found indicates that Europa has a much greater impact than hitherto believed on the structure of, and the energy flow within, Jupiter's magnetosphere.
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Affiliation(s)
- B H Mauk
- The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, Maryland 20723, USA.
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42
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Mauk BH, Clarke JT, Grodent D, Waite JH, Paranicas CP, Williams DJ. Transient aurora on Jupiter from injections of magnetospheric electrons. Nature 2002; 415:1003-5. [PMID: 11875562 DOI: 10.1038/4151003a] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Energetic electrons and ions that are trapped in Earth's magnetosphere can suddenly be accelerated towards the planet. Some dynamic features of Earth's aurora (the northern and southern lights) are created by the fraction of these injected particles that travels along magnetic field lines and hits the upper atmosphere. Jupiter's aurora appears similar to Earth's in some respects; both appear as large ovals circling the poles and both show transient events. But the magnetospheres of Jupiter and Earth are so different---particularly in the way they are powered---that it is not known whether the magnetospheric drivers of Earth's aurora also cause them on Jupiter. Here we show a direct relationship between Earth-like injections of electrons in Jupiter's magnetosphere and a transient auroral feature in Jupiter's polar region. This relationship is remarkably similar to what happens at Earth, and therefore suggests that despite the large differences between planetary magnetospheres, some processes that generate aurorae are the same throughout the Solar System.
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Affiliation(s)
- B H Mauk
- The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, Maryland 20723, USA.
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43
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Mauk BH, Williams DJ, Eviatar A. Understanding Io's space environment interaction: Recent energetic electron measurements from Galileo. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/2000ja002508] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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44
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Nosé M, Lui ATY, Ohtani S, Mauk BH, McEntire RW, Williams DJ, Mukai T, Yumoto K. Acceleration of oxygen ions of ionospheric origin in the near-Earth magnetotail during substorms. ACTA ACUST UNITED AC 2000. [DOI: 10.1029/1999ja000318] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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45
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Mauk BH, Williams DJ, McEntire RW, Khurana KK, Roederer JG. Storm-like dynamics of Jupiter's inner and middle magnetosphere. ACTA ACUST UNITED AC 1999. [DOI: 10.1029/1999ja900097] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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46
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Waite JH, Gladstone GR, Lewis WS, Drossart P, Cravens TE, Maurellis AN, Mauk BH, Miller S. Equatorial X-ray Emissions: Implications for Jupiter's High Exospheric Temperatures. Science 1997; 276:104-8. [PMID: 9082978 DOI: 10.1126/science.276.5309.104] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Observations with the High Resolution Imager on the Rontgensatellit reveal x-ray emissions from Jupiter's equatorial latitudes. The observed emissions probably result from the precipitation of energetic (>300 kiloelectron volts per atomic mass unit) sulfur and oxygen ions out of Jupiter's inner radiation belt. Model calculations of the energy deposition by such heavy ion precipitation and of the resulting atmospheric heating rates indicate that this energy source can contribute to the high exospheric temperatures(>800 kelvin at 0.01 microbar) measured by the Galileo probe's Atmospheric Structure Instrument. Low-latitude energetic particle precipitation must therefore be considered, in addition to other proposed mechanisms such as gravity waves and soft electron precipitation, as an important source of heat for Jupiter's thermosphere.
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Affiliation(s)
- JH Waite
- J. H. Waite Jr., G. R. Gladstone, W. S. Lewis, Department of Space Science, Southwest Research Institute, Post Office Box 28510, San Antonio, TX 78228-0510, USA. P. Drossart, DESPA, Observatoire de Paris, F-92195 Meudon Cedex, France. T. E. Cravens and A. N. Maurellis, Department of Physics and Astronomy, University of Kansas, Lawrence, KS 66045-2151, USA. B. H. Mauk, Applied Physics Laboratory, The Johns Hopkins University, Laurel, MD 20723-6099, USA. S. Miller, Department of History, Philosophy, and Communication in Science, University College London, London WC1E 6BT, UK
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47
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Williams DJ, Mauk BH, McEntire RE, Roelof EC, Armstrong TP, Wilken B, Roederer JG, Krimigis SM, Fritz TA, Lanzerotti LJ. Electron beams and ion composition measured at Io and in its torus. Science 1996; 274:401-3. [PMID: 8832885 DOI: 10.1126/science.274.5286.401] [Citation(s) in RCA: 108] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Intense, magnetic field-aligned, bidirectional, energetic (>15 kiloelectron volts) electron beams were discovered by the Galileo energetic particles detector during the flyby of Io. These beams can carry sufficient energy flux into Jupiter's atmosphere to produce a visible aurora at the footprint of the magnetic flux tube connecting Io to Jupiter. Composition measurements through the torus showed that the spatial distributions of protons, oxygen, and sulfur are different, with sulfur being the dominant energetic (> approximately 10 kiloelectron volts per nucleon) ion at closest approach.
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Affiliation(s)
- D J Williams
- Johns Hopkins Applied Physics Laboratory, Johns Hopkins Road, Laurel, MD 20723, USA
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48
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Maurice S, Sittler EC, Cooper JF, Mauk BH, Blanc M, Selesnick RS. Comprehensive analysis of electron observations at Saturn: Voyager 1 and 2. ACTA ACUST UNITED AC 1996. [DOI: 10.1029/96ja00765] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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49
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Mauk BH, Gary SA, Kane M, Keath EP, Krimigis SM, Armstrong TP. Hot plasma parameters of Jupiter's inner magnetosphere. ACTA ACUST UNITED AC 1996. [DOI: 10.1029/96ja00006] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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50
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Kane M, Mauk BH, Keath EP, Krimigis SM. Hot ions in Jupiter's magnetodisc: A model for Voyager 2 low-energy charged particle measurements. ACTA ACUST UNITED AC 1995. [DOI: 10.1029/95ja00793] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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