1
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Daggitt TA, Horne RB, Glauert SA, Del Zanna G, Albert JM. Chorus wave power at the strong diffusion limit overcomes electron losses due to strong diffusion. Nat Commun 2024; 15:1800. [PMID: 38413603 PMCID: PMC10899562 DOI: 10.1038/s41467-024-45967-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 02/07/2024] [Indexed: 02/29/2024] Open
Abstract
Earth's radiation belts consist of high-energy charged particles trapped by Earth's magnetic field. Strong pitch angle diffusion of electrons caused by wave-particle interaction in Earth's radiation belts has primarily been considered as a loss process, as trapped electrons are rapidly diffused into the loss cone and lost to the atmosphere. However, the wave power necessary to produce strong diffusion should also produce rapid energy diffusion, and has not been considered in this context. Here we provide evidence of strong diffusion using satellite data. We use two-dimensional Fokker-Planck simulations of electron diffusion in pitch angle and energy to show that scaling up chorus wave power to the strong diffusion limit produces rapid acceleration of electrons, sufficient to outweigh the losses due to strong diffusion. The rate of losses saturates at the strong diffusion limit, whilst the rate of acceleration does not. This leads to the surprising result of an increase, not a decrease in the trapped electron population during strong diffusion due to chorus waves as expected when treating strong diffusion as a loss process. Our results suggest there is a tipping point in chorus wave power between net loss and net acceleration that global radiation belt models need to capture to better forecast hazardous radiation levels that damage satellites.
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Affiliation(s)
- T A Daggitt
- British Antarctic Survey, Cambridge, UK.
- Department of Applied Maths and Theoretical Physics, University of Cambridge, Cambridge, UK.
| | - R B Horne
- British Antarctic Survey, Cambridge, UK
| | | | - G Del Zanna
- Department of Applied Maths and Theoretical Physics, University of Cambridge, Cambridge, UK
| | - J M Albert
- Air Force Research Laboratory, Kirtland AFB, NM, USA
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2
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Woodfield EE, Glauert SA, Menietti JD, Horne RB, Kavanagh AJ, Shprits YY. Acceleration of Electrons by Whistler-Mode Hiss Waves at Saturn. GEOPHYSICAL RESEARCH LETTERS 2022; 49:e2021GL096213. [PMID: 35864852 PMCID: PMC9286411 DOI: 10.1029/2021gl096213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 12/01/2021] [Accepted: 12/27/2021] [Indexed: 06/15/2023]
Abstract
Plasmaspheric hiss waves at the Earth are well known for causing losses of electrons from the radiation belts through wave particle interactions. At Saturn, however, we show that the different plasma density environment leads to acceleration of the electrons rather than loss. The ratio of plasma frequency to electron gyrofrequency frequently falls below one creating conditions for hiss to accelerate electrons. The location of hiss at high latitudes (>25°) coincides very well with this region of very low density. The interaction between electrons and hiss only occurs at these higher latitudes, therefore the acceleration is limited to mid to low pitch angles leading to butterfly pitch angle distributions. The hiss is typically an order of magnitude stronger than chorus at Saturn and the resulting acceleration is rapid, approaching steady state in one day at 0.4 MeV at L = 7 and the effect is stronger with increasing L-shell.
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3
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Yao Z, Dunn WR, Woodfield EE, Clark G, Mauk BH, Ebert RW, Grodent D, Bonfond B, Pan D, Rae IJ, Ni B, Guo R, Branduardi-Raymont G, Wibisono AD, Rodriguez P, Kotsiaros S, Ness JU, Allegrini F, Kurth WS, Gladstone GR, Kraft R, Sulaiman AH, Manners H, Desai RT, Bolton SJ. Revealing the source of Jupiter's x-ray auroral flares. SCIENCE ADVANCES 2021; 7:7/28/eabf0851. [PMID: 34244139 PMCID: PMC8270495 DOI: 10.1126/sciadv.abf0851] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 05/28/2021] [Indexed: 06/13/2023]
Abstract
Jupiter's rapidly rotating, strong magnetic field provides a natural laboratory that is key to understanding the dynamics of high-energy plasmas. Spectacular auroral x-ray flares are diagnostic of the most energetic processes governing magnetospheres but seemingly unique to Jupiter. Since their discovery 40 years ago, the processes that produce Jupiter's x-ray flares have remained unknown. Here, we report simultaneous in situ satellite and space-based telescope observations that reveal the processes that produce Jupiter's x-ray flares, showing surprising similarities to terrestrial ion aurora. Planetary-scale electromagnetic waves are observed to modulate electromagnetic ion cyclotron waves, periodically causing heavy ions to precipitate and produce Jupiter's x-ray pulses. Our findings show that ion aurorae share common mechanisms across planetary systems, despite temporal, spatial, and energetic scales varying by orders of magnitude.
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Affiliation(s)
- Zhonghua Yao
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China.
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - William R Dunn
- Mullard Space Science Laboratory, University College London, Dorking, UK
- Harvard-Smithsonian Center for Astrophysics, Smithsonian Astrophysical Observatory, Cambridge, MA, USA
- The Centre for Planetary Science at UCL/Birkbeck, Gower Street, London WC1E 6BT, UK
| | | | - George Clark
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD, USA
| | - Barry H Mauk
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD, USA
| | - Robert W Ebert
- Space Science and Engineering Division, Southwest Research Institute, San Antonio, TX, USA
- Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX, USA
| | - Denis Grodent
- Laboratoire de Physique Atmosphérique et Planétaire, STAR institute, Université de Liège, Liège, Belgium
| | - Bertrand Bonfond
- Laboratoire de Physique Atmosphérique et Planétaire, STAR institute, Université de Liège, Liège, Belgium
| | - Dongxiao Pan
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
| | | | - Binbin Ni
- Department of Space Physics, School of Electronic Information, Wuhan University, Wuhan, Hubei, China
- CAS Center for Excellence in Comparative Planetology, Hefei, Anhui, China
| | - Ruilong Guo
- Laboratoire de Physique Atmosphérique et Planétaire, STAR institute, Université de Liège, Liège, Belgium
| | | | - Affelia D Wibisono
- Mullard Space Science Laboratory, University College London, Dorking, UK
- The Centre for Planetary Science at UCL/Birkbeck, Gower Street, London WC1E 6BT, UK
| | - Pedro Rodriguez
- European Space Agency (ESA), European Space Astronomy Centre (ESAC), Camino Bajo del Castillo s/n, 28692 Villanueva de la Cañada, Madrid, Spain
| | | | - Jan-Uwe Ness
- European Space Agency (ESA), European Space Astronomy Centre (ESAC), Camino Bajo del Castillo s/n, 28692 Villanueva de la Cañada, Madrid, Spain
| | - Frederic Allegrini
- Space Science and Engineering Division, Southwest Research Institute, San Antonio, TX, USA
- Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX, USA
| | - William S Kurth
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA, USA
| | - G Randall Gladstone
- Space Science and Engineering Division, Southwest Research Institute, San Antonio, TX, USA
- Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX, USA
| | - Ralph Kraft
- Harvard-Smithsonian Center for Astrophysics, Smithsonian Astrophysical Observatory, Cambridge, MA, USA
| | - Ali H Sulaiman
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA, USA
| | - Harry Manners
- Blackett Laboratory, Imperial College London, London, UK
| | | | - Scott J Bolton
- Space Science and Engineering Division, Southwest Research Institute, San Antonio, TX, USA
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4
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Hua M, Li W, Ni B, Ma Q, Green A, Shen X, Claudepierre SG, Bortnik J, Gu X, Fu S, Xiang Z, Reeves GD. Very-Low-Frequency transmitters bifurcate energetic electron belt in near-earth space. Nat Commun 2020; 11:4847. [PMID: 32973130 PMCID: PMC7518438 DOI: 10.1038/s41467-020-18545-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 08/31/2020] [Indexed: 11/17/2022] Open
Abstract
Very-Low-Frequency (VLF) transmitters operate worldwide mostly at frequencies of 10-30 kilohertz for submarine communications. While it has been of intense scientific interest and practical importance to understand whether VLF transmitters can affect the natural environment of charged energetic particles, for decades there remained little direct observational evidence that revealed the effects of these VLF transmitters in geospace. Here we report a radially bifurcated electron belt formation at energies of tens of kiloelectron volts (keV) at altitudes of ~0.8-1.5 Earth radii on timescales over 10 days. Using Fokker-Planck diffusion simulations, we provide quantitative evidence that VLF transmitter emissions that leak from the Earth-ionosphere waveguide are primarily responsible for bifurcating the energetic electron belt, which typically exhibits a single-peak radial structure in near-Earth space. Since energetic electrons pose a potential danger to satellite operations, our findings demonstrate the feasibility of mitigation of natural particle radiation environment.
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Affiliation(s)
- Man Hua
- Department of Space Physics, School of Electronic Information, Wuhan University, Wuhan, Hubei, China
- Center for Space Physics, Boston University, Boston, MA, USA
| | - Wen Li
- Center for Space Physics, Boston University, Boston, MA, USA.
| | - Binbin Ni
- Department of Space Physics, School of Electronic Information, Wuhan University, Wuhan, Hubei, China.
- CAS Center for Excellence in Comparative Planetology, Anhui, Hefei, China.
| | - Qianli Ma
- Center for Space Physics, Boston University, Boston, MA, USA
- Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, CA, USA
| | - Alex Green
- Center for Space Physics, Boston University, Boston, MA, USA
| | - Xiaochen Shen
- Center for Space Physics, Boston University, Boston, MA, USA
| | - Seth G Claudepierre
- Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, CA, USA
- Space Sciences Department, The Aerospace Corporation, EI Segundo, CA, USA
| | - Jacob Bortnik
- Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, CA, USA
| | - Xudong Gu
- Department of Space Physics, School of Electronic Information, Wuhan University, Wuhan, Hubei, China
| | - Song Fu
- Department of Space Physics, School of Electronic Information, Wuhan University, Wuhan, Hubei, China
| | - Zheng Xiang
- Department of Space Physics, School of Electronic Information, Wuhan University, Wuhan, Hubei, China
| | - Geoffrey D Reeves
- Space Science and Applications Group, Los Alamos National Laboratory, Los Alamos, NM, USA
- Space Sciences Division, New Mexico Consortium, Los Alamos, NM, USA
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5
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Woodfield EE, Glauert SA, Menietti JD, Averkamp TF, Horne RB, Shprits YY. Rapid Electron Acceleration in Low-Density Regions of Saturn's Radiation Belt by Whistler Mode Chorus Waves. GEOPHYSICAL RESEARCH LETTERS 2019; 46:7191-7198. [PMID: 31598019 PMCID: PMC6772095 DOI: 10.1029/2019gl083071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 05/30/2019] [Accepted: 06/17/2019] [Indexed: 06/10/2023]
Abstract
Electron acceleration at Saturn due to whistler mode chorus waves has previously been assumed to be ineffective; new data closer to the planet show it can be very rapid (factor of 104 flux increase at 1 MeV in 10 days compared to factor of 2). A full survey of chorus waves at Saturn is combined with an improved plasma density model to show that where the plasma frequency falls below the gyrofrequency additional strong resonances are observed favoring electron acceleration. This results in strong chorus acceleration between approximately 2.5 R S and 5.5 R S outside which adiabatic transport may dominate. Strong pitch angle dependence results in butterfly pitch angle distributions that flatten over a few days at 100s keV, tens of days at MeV energies which may explain observations of butterfly distributions of MeV electrons near L=3. Including cross terms in the simulations increases the tendency toward butterfly distributions.
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Affiliation(s)
| | | | - J. D. Menietti
- Department of Physics and AstronomyUniversity of IowaIowa CityIAUSA
| | - T. F. Averkamp
- Department of Physics and AstronomyUniversity of IowaIowa CityIAUSA
| | | | - Y. Y. Shprits
- Helmholtz Centre Potsdam, GFZ German Research Centre for GeosciencesPotsdamGermany
- Institute for Physics and AstronomyUniversität PotsdamPotsdamGermany
- Department of Earth, Planetary, and Space SciencesUniversity of CaliforniaLos AngelesCAUSA
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6
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Woodfield EE, Horne RB, Glauert SA, Menietti JD, Shprits YY, Kurth WS. Formation of electron radiation belts at Saturn by Z-mode wave acceleration. Nat Commun 2018; 9:5062. [PMID: 30498204 PMCID: PMC6265320 DOI: 10.1038/s41467-018-07549-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 11/07/2018] [Indexed: 11/16/2022] Open
Abstract
At Saturn electrons are trapped in the planet's magnetic field and accelerated to relativistic energies to form the radiation belts, but how this dramatic increase in electron energy occurs is still unknown. Until now the mechanism of radial diffusion has been assumed but we show here that in-situ acceleration through wave particle interactions, which initial studies dismissed as ineffectual at Saturn, is in fact a vital part of the energetic particle dynamics there. We present evidence from numerical simulations based on Cassini spacecraft data that a particular plasma wave, known as Z-mode, accelerates electrons to MeV energies inside 4 RS (1 RS = 60,330 km) through a Doppler shifted cyclotron resonant interaction. Our results show that the Z-mode waves observed are not oblique as previously assumed and are much better accelerators than O-mode waves, resulting in an electron energy spectrum that closely approaches observed values without any transport effects included.
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Affiliation(s)
- E E Woodfield
- British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, UK.
| | - R B Horne
- British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, UK
| | - S A Glauert
- British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, UK
| | - J D Menietti
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA, 52242, USA
| | - Y Y Shprits
- Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Potsdam, 14473, Germany
- Institute for Physics and Astronomy, Universität Potsdam, 14469, Potsdam, Germany
- Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, CA, 90095, USA
| | - W S Kurth
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA, 52242, USA
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7
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Horne RB, Phillips MW, Glauert SA, Meredith NP, Hands ADP, Ryden KA, Li W. Realistic Worst Case for a Severe Space Weather Event Driven by a Fast Solar Wind Stream. SPACE WEATHER : THE INTERNATIONAL JOURNAL OF RESEARCH & APPLICATIONS 2018; 16:1202-1215. [PMID: 31031572 PMCID: PMC6473668 DOI: 10.1029/2018sw001948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 07/19/2018] [Accepted: 08/01/2018] [Indexed: 06/09/2023]
Abstract
Satellite charging is one of the most important risks for satellites on orbit. Satellite charging can lead to an electrostatic discharge resulting in component damage, phantom commands, and loss of service and in exceptional cases total satellite loss. Here we construct a realistic worst case for a fast solar wind stream event lasting 5 days or more and use a physical model to calculate the maximum electron flux greater than 2 MeV for geostationary orbit. We find that the flux tends toward a value of 106 cm-2·s-1·sr-1 after 5 days and remains high for another 5 days. The resulting flux is comparable to a 1 in 150-year event found from an independent statistical analysis of electron data. Approximately 2.5 mm of Al shielding would be required to reduce the internal charging current to below the National Aeronautics and Space Administration-recommended guidelines, much more than is currently used. Thus, we would expect many satellites to report electrostatic discharge anomalies during such an event with a strong likelihood of service outage and total satellite loss. We conclude that satellites at geostationary orbit are more likely to be at risk from fast solar wind stream event than a Carrington-type storm.
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Affiliation(s)
| | | | | | | | | | | | - Wen Li
- Center for Space PhysicsBoston UniversityBostonMAUSA
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8
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Artemyev A, Agapitov O, Mourenas D, Krasnoselskikh V, Mozer F. Wave energy budget analysis in the Earth's radiation belts uncovers a missing energy. Nat Commun 2015; 6:8143. [PMID: 25975615 PMCID: PMC4479018 DOI: 10.1038/ncomms8143] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 04/10/2015] [Indexed: 11/08/2022] Open
Abstract
Whistler-mode emissions are important electromagnetic waves pervasive in the Earth's magnetosphere, where they continuously remove or energize electrons trapped by the geomagnetic field, controlling radiation hazards to satellites and astronauts and the upper-atmosphere ionization or chemical composition. Here, we report an analysis of 10-year Cluster data, statistically evaluating the full wave energy budget in the Earth's magnetosphere, revealing that a significant fraction of the energy corresponds to hitherto generally neglected very oblique waves. Such waves, with 10 times smaller magnetic power than parallel waves, typically have similar total energy. Moreover, they carry up to 80% of the wave energy involved in wave-particle resonant interactions. It implies that electron heating and precipitation into the atmosphere may have been significantly under/over-valued in past studies considering only conventional quasi-parallel waves. Very oblique waves may turn out to be a crucial agent of energy redistribution in the Earth's radiation belts, controlled by solar activity.
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Affiliation(s)
- A.V. Artemyev
- LPC2E/CNRS, 3A, Avenue de la Recherche Scientifique, 45071 Orleans Cedex 2, France
| | - O.V. Agapitov
- Space Sciences Laboratory, University of California, 7 Gauss Way, Berkeley, California 94720, USA
| | - D. Mourenas
- CEA, DAM, DIF, F-91297 Arpajon Cedex, France
| | - V.V. Krasnoselskikh
- LPC2E/CNRS, 3A, Avenue de la Recherche Scientifique, 45071 Orleans Cedex 2, France
| | - F.S. Mozer
- Space Sciences Laboratory, University of California, 7 Gauss Way, Berkeley, California 94720, USA
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9
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Abstract
Earth's proton aurora occurs over a broad MLT region and is produced by the precipitation of low-energy (2–10 keV) plasmasheet protons. Proton precipitation can alter chemical compositions of the atmosphere, linking solar activity with global climate variability. Previous studies proposed that electromagnetic ion cyclotron waves can resonate with protons, producing proton scattering precipitation. A long-outstanding question still remains whether there is another mechanism responsible for the proton aurora. Here, by performing satellite data analysis and diffusion equation calculations, we show that fast magnetosonic waves can produce trapped proton scattering that yields proton aurora. This provides a new insight into the mechanism of proton aurora. Furthermore, a ray-tracing study demonstrates that magnetosonic wave propagates over a broad MLT region, consistent with the global distribution of proton aurora.
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10
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Xiao F, Zong Q, Su Z, Yang C, He Z, Wang Y, Gao Z. Determining the mechanism of cusp proton aurora. Sci Rep 2013; 3:1654. [PMID: 23575366 PMCID: PMC3622916 DOI: 10.1038/srep01654] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 04/02/2013] [Indexed: 11/23/2022] Open
Abstract
Earth's cusp proton aurora occurs near the prenoon and is primarily produced by the precipitation of solar energetic (2–10 keV) protons. Cusp auroral precipitation provides a direct source of energy for the high-latitude dayside upper atmosphere, contributing to chemical composition change and global climate variability. Previous studies have indicated that magnetic reconnection allows solar energetic protons to cross the magnetopause and enter the cusp region, producing cusp auroral precipitation. However, energetic protons are easily trapped in the cusp region due to a minimum magnetic field existing there. Hence, the mechanism of cusp proton aurora has remained a significant challenge for tens of years. Based on the satellite data and calculations of diffusion equation, we demonstrate that EMIC waves can yield the trapped proton scattering that causes cusp proton aurora. This moves forward a step toward identifying the generation mechanism of cusp proton aurora.
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Affiliation(s)
- Fuliang Xiao
- School of Physics and Electronic Sciences, Changsha University of Science and Technology, Changsha 410004, China.
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11
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Tao X, Bortnik J, Albert JM, Thorne RM. Comparison of bounce-averaged quasi-linear diffusion coefficients for parallel propagating whistler mode waves with test particle simulations. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2012ja017931] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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12
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Albert JM. Dependence of quasi-linear diffusion coefficients on wave parameters. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2012ja017718] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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13
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Orlova KG, Shprits YY, Ni B. Bounce-averaged diffusion coefficients due to resonant interaction of the outer radiation belt electrons with oblique chorus waves computed in a realistic magnetic field model. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2012ja017591] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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14
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Subbotin DA, Shprits YY. Three-dimensional radiation belt simulations in terms of adiabatic invariants using a single numerical grid. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011ja017467] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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15
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Shprits Y, Daae M, Ni B. Statistical analysis of phase space density buildups and dropouts. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011ja016939] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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16
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Bortnik J, Chen L, Li W, Thorne RM, Meredith NP, Horne RB. Modeling the wave power distribution and characteristics of plasmaspheric hiss. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011ja016862] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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17
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Subbotin DA, Shprits YY, Ni B. Long-term radiation belt simulation with the VERB 3-D code: Comparison with CRRES observations. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011ja017019] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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18
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Li W, Bortnik J, Thorne RM, Angelopoulos V. Global distribution of wave amplitudes and wave normal angles of chorus waves using THEMIS wave observations. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011ja017035] [Citation(s) in RCA: 202] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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19
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Subbotin DA, Shprits YY, Gkioulidou M, Lyons LR, Ni B, Merkin VG, Toffoletto FR, Thorne RM, Horne R, Hudson MK. Simulation of the acceleration of relativistic electrons in the inner magnetosphere using RCM-VERB coupled codes. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010ja016350] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- D. A. Subbotin
- Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles California USA
| | - Y. Y. Shprits
- Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles California USA
- Institute of Geophysics and Planetary Physics; University of California; Los Angeles California USA
| | - M. Gkioulidou
- Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles California USA
| | - L. R. Lyons
- Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles California USA
| | - B. Ni
- Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles California USA
| | - V. G. Merkin
- Center for Space Physics; Boston University; Boston Massachusetts USA
| | - F. R. Toffoletto
- Department of Space Physics and Astronomy; William Marsh Rice University; Houston Texas USA
| | - R. M. Thorne
- Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles California USA
| | - R.B. Horne
- British Antarctic Survey; Natural Environment Research Council; Cambridge UK
| | - M. K. Hudson
- Department of Physics and Astronomy; Dartmouth College; Hanover New Hampshire USA
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20
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Schippers P, Arridge CS, Menietti JD, Gurnett DA, Lamy L, Cecconi B, Mitchell DG, André N, Kurth WS, Grimald S, Dougherty MK, Coates AJ, Krupp N, Young DT. Auroral electron distributions within and close to the Saturn kilometric radiation source region. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011ja016461] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- P. Schippers
- Department of Physics and Astronomy; University of Iowa; Iowa City Iowa USA
| | - C. S. Arridge
- Mullard Space Science Laboratory; University College London; Holmbury St. Mary UK
- Centre for Planetary Sciences at UCL/Birkbeck; London WC1E 6BT UK
| | - J. D. Menietti
- Department of Physics and Astronomy; University of Iowa; Iowa City Iowa USA
| | - D. A. Gurnett
- Department of Physics and Astronomy; University of Iowa; Iowa City Iowa USA
| | - L. Lamy
- Department of Space and Atmospheric Physics; Imperial College; London UK
- LESIA, CNRS; Observatoire de Meudon; Meudon France
| | - B. Cecconi
- LESIA, CNRS; Observatoire de Meudon; Meudon France
| | - D. G. Mitchell
- Applied Physics Laboratory; Johns Hopkins University; Laurel Maryland USA
| | - N. André
- Centre d'Étude Spatiale des Rayonnements; Université de Toulouse, UPS; Toulouse France
- CNRS UMR 5187; Toulouse France
| | - W. S. Kurth
- Department of Physics and Astronomy; University of Iowa; Iowa City Iowa USA
| | - S. Grimald
- Centre d'Étude Spatiale des Rayonnements; Université de Toulouse, UPS; Toulouse France
- CNRS UMR 5187; Toulouse France
| | - M. K. Dougherty
- Department of Space and Atmospheric Physics; Imperial College; London UK
| | - A. J. Coates
- Mullard Space Science Laboratory; University College London; Holmbury St. Mary UK
- Centre for Planetary Sciences at UCL/Birkbeck; London WC1E 6BT UK
| | - N. Krupp
- Max-Planck-Institut fur Sonnensystemforschung; Katlenburg-Lindau Germany
| | - D. T. Young
- Southwest Research Institute; San Antonio Texas USA
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21
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Su Z, Zheng H, Wang S. Three-dimensional simulation of energetic outer zone electron dynamics due to wave-particle interaction and azimuthal advection. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009ja014980] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Zhenpeng Su
- Mengcheng National Geophysical Observatory, School of Earth and Space Sciences; University of Science and Technology of China; Hefei China
| | - Huinan Zheng
- Mengcheng National Geophysical Observatory, School of Earth and Space Sciences; University of Science and Technology of China; Hefei China
| | - Shui Wang
- Mengcheng National Geophysical Observatory, School of Earth and Space Sciences; University of Science and Technology of China; Hefei China
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22
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Xiao F, Su Z, Zheng H, Wang S. Three-dimensional simulations of outer radiation belt electron dynamics including cross-diffusion terms. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009ja014541] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Fuliang Xiao
- School of Physics and Electronic Sciences; Changsha University of Science and Technology; Changsha China
| | - Zhenpeng Su
- Chinese Academy of Sciences Key Laboratory for Basic Plasma Physics, School of Earth and Space Sciences; University of Science and Technology of China; Hefei China
| | - Huinan Zheng
- Chinese Academy of Sciences Key Laboratory for Basic Plasma Physics, School of Earth and Space Sciences; University of Science and Technology of China; Hefei China
| | - Shui Wang
- Chinese Academy of Sciences Key Laboratory for Basic Plasma Physics, School of Earth and Space Sciences; University of Science and Technology of China; Hefei China
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23
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Lam MM, Horne RB, Meredith NP, Glauert SA, Moffat-Griffin T, Green JC. Origin of energetic electron precipitation >30 keV into the atmosphere. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009ja014619] [Citation(s) in RCA: 145] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Mai Mai Lam
- Department of Physics and Astronomy; University of Leicester; Leicester UK
| | - Richard B. Horne
- British Antarctic Survey; Natural Environment Research Council; Cambridge UK
| | - Nigel P. Meredith
- British Antarctic Survey; Natural Environment Research Council; Cambridge UK
| | - Sarah A. Glauert
- British Antarctic Survey; Natural Environment Research Council; Cambridge UK
| | | | - Janet C. Green
- Space Weather Prediction Center; National Oceanic and Atmospheric Administration; Boulder Colorado USA
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24
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Liu K, Lemons DS, Winske D, Gary SP. Relativistic electron scattering by electromagnetic ion cyclotron fluctuations: Test particle simulations. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009ja014807] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Kaijun Liu
- Los Alamos National Laboratory; Los Alamos New Mexico USA
| | - Don S. Lemons
- Department of Physics; Bethel College; North Newton Kansas USA
| | - Dan Winske
- Los Alamos National Laboratory; Los Alamos New Mexico USA
| | - S. Peter Gary
- Los Alamos National Laboratory; Los Alamos New Mexico USA
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25
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Subbotin D, Shprits Y, Ni B. Three-dimensional VERB radiation belt simulations including mixed diffusion. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009ja015070] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Dmitriy Subbotin
- Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles California USA
| | - Yuri Shprits
- Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles California USA
- Institute of Geophysics and Planetary Physics; University of California; Los Angeles California USA
| | - Binbin Ni
- Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles California USA
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26
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Li LY, Cao JB, Zhou GC, Li X. Statistical roles of storms and substorms in changing the entire outer zone relativistic electron population. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2009ja014333] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- L. Y. Li
- State Key Laboratory for Space Weather, Center for Space Science and Applied Research; Chinese Academy of Sciences; Beijing China
| | - J. B. Cao
- School of Astronautics; Beijing University of Aeronautics and Astronautics; Beijing China
| | - G. C. Zhou
- State Key Laboratory for Space Weather, Center for Space Science and Applied Research; Chinese Academy of Sciences; Beijing China
| | - X. Li
- Laboratory for Atmospheric and Space Physics; University of Colorado at Boulder; Boulder Colorado USA
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27
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Shprits YY, Subbotin D, Ni B. Evolution of electron fluxes in the outer radiation belt computed with the VERB code. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008ja013784] [Citation(s) in RCA: 164] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Yuri Y. Shprits
- Institute of Geophysics and Planetary Physics; University of California; Los Angeles California USA
- Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles California USA
| | - Dmitri Subbotin
- Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles California USA
| | - Binbin Ni
- Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles California USA
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28
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Shprits YY, Ni B. Dependence of the quasi-linear scattering rates on the wave normal distribution of chorus waves. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2009ja014223] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Yuri Y. Shprits
- Institute of Geophysics and Planetary Physics; University of California; Los Angeles California USA
- Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles California USA
| | - Binbin Ni
- Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles California USA
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29
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Albert JM, Meredith NP, Horne RB. Three-dimensional diffusion simulation of outer radiation belt electrons during the 9 October 1990 magnetic storm. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2009ja014336] [Citation(s) in RCA: 149] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Jay M. Albert
- Space Vehicles Directorate; Air Force Research Laboratory; Hanscom Air Force Base Massachusetts USA
| | - Nigel P. Meredith
- British Antarctic Survey; Natural Environment Research Council; Cambridge UK
| | - Richard B. Horne
- British Antarctic Survey; Natural Environment Research Council; Cambridge UK
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30
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Meredith NP, Horne RB, Glauert SA, Baker DN, Kanekal SG, Albert JM. Relativistic electron loss timescales in the slot region. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008ja013889] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Nigel P. Meredith
- British Antarctic Survey, Natural Environment Research Council; Cambridge UK
| | - Richard B. Horne
- British Antarctic Survey, Natural Environment Research Council; Cambridge UK
| | - Sarah A. Glauert
- British Antarctic Survey, Natural Environment Research Council; Cambridge UK
| | - Daniel N. Baker
- Laboratory for Atmospheric and Space Physics; University of Colorado; Boulder Colorado USA
| | - Shrikanth G. Kanekal
- Laboratory for Atmospheric and Space Physics; University of Colorado; Boulder Colorado USA
| | - Jay M. Albert
- Space Vehicles Directorate, Air Force Research Laboratory; Hanscom Air Force Base Massachusetts USA
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31
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Xiao F, Su Z, Zheng H, Wang S. Modeling of outer radiation belt electrons by multidimensional diffusion process. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008ja013580] [Citation(s) in RCA: 153] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Fuliang Xiao
- School of Physics and Electronic Sciences; Changsha University of Science and Technology; Changsha China
| | - Zhenpeng Su
- Key Laboratory for Basic Plasma Physics, Chinese Academy of Sciences, School of Earth and Space Sciences; University of Science and Technology of China; Hefei China
| | - Huinan Zheng
- Key Laboratory for Basic Plasma Physics, Chinese Academy of Sciences, School of Earth and Space Sciences; University of Science and Technology of China; Hefei China
| | - Shui Wang
- Key Laboratory for Basic Plasma Physics, Chinese Academy of Sciences, School of Earth and Space Sciences; University of Science and Technology of China; Hefei China
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32
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Varotsou A, Boscher D, Bourdarie S, Horne RB, Meredith NP, Glauert SA, Friedel RH. Three-dimensional test simulations of the outer radiation belt electron dynamics including electron-chorus resonant interactions. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007ja012862] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Athina Varotsou
- Space Science and Applications; Los Alamos National Laboratory; Los Alamos New Mexico USA
| | - Daniel Boscher
- Office National d’Etudes et Recherches Aérospatiales; Toulouse France
| | | | - Richard B. Horne
- British Antarctic Survey; Natural Environment Research Council; Cambridge UK
| | - Nigel P. Meredith
- British Antarctic Survey; Natural Environment Research Council; Cambridge UK
| | - Sarah A. Glauert
- British Antarctic Survey; Natural Environment Research Council; Cambridge UK
| | - Reiner H. Friedel
- Space Science and Applications; Los Alamos National Laboratory; Los Alamos New Mexico USA
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33
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Jordanova VK, Albert J, Miyoshi Y. Relativistic electron precipitation by EMIC waves from self-consistent global simulations. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2008ja013239] [Citation(s) in RCA: 202] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | - J. Albert
- Air Force Research Laboratory; Hanscom AFB Massachusetts USA
| | - Y. Miyoshi
- Solar-Terrestrial Environment Laboratory; Nagoya University; Nagoya Japan
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34
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Fok MC, Horne RB, Meredith NP, Glauert SA. Radiation Belt Environment model: Application to space weather nowcasting. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007ja012558] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Mei-Ching Fok
- Geospace Physics Laboratory; NASA Goddard Space Flight Center; Greenbelt Maryland USA
| | - Richard B. Horne
- Physical Sciences Division; British Antarctic Survey; Cambridge UK
| | | | - Sarah A. Glauert
- Physical Sciences Division; British Antarctic Survey; Cambridge UK
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35
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Affiliation(s)
- J. M. Albert
- Air Force Research Laboratory; Space Vehicles Directorate; Hanscom Air Force Base Massachusetts USA
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36
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Li W, Shprits YY, Thorne RM. Dynamic evolution of energetic outer zone electrons due to wave-particle interactions during storms. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2007ja012368] [Citation(s) in RCA: 285] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- W. Li
- Department of Atmospheric and Oceanic Sciences; University of California Los Angeles; Los Angeles California USA
| | - Y. Y. Shprits
- Department of Atmospheric and Oceanic Sciences; University of California Los Angeles; Los Angeles California USA
| | - R. M. Thorne
- Department of Atmospheric and Oceanic Sciences; University of California Los Angeles; Los Angeles California USA
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37
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Meredith NP, Horne RB, Glauert SA, Anderson RR. Slot region electron loss timescales due to plasmaspheric hiss and lightning-generated whistlers. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2007ja012413] [Citation(s) in RCA: 211] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Nigel P. Meredith
- British Antarctic Survey; Natural Environment Research Council; Cambridge UK
| | - Richard B. Horne
- British Antarctic Survey; Natural Environment Research Council; Cambridge UK
| | - Sarah A. Glauert
- British Antarctic Survey; Natural Environment Research Council; Cambridge UK
| | - Roger R. Anderson
- Department of Physics and Astronomy; University of Iowa; Iowa City Iowa USA
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38
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Affiliation(s)
- M. Kaan Öztürk
- Department of Physics and Astronomy; Rice University; Houston Texas USA
| | - R. A. Wolf
- Department of Physics and Astronomy; Rice University; Houston Texas USA
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39
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Thorne RM, Shprits YY, Meredith NP, Horne RB, Li W, Lyons LR. Refilling of the slot region between the inner and outer electron radiation belts during geomagnetic storms. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006ja012176] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- R. M. Thorne
- Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles California USA
| | - Y. Y. Shprits
- Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles California USA
| | - N. P. Meredith
- British Antarctic Survey; Natural Environment Research Council; Cambridge UK
| | - R. B. Horne
- British Antarctic Survey; Natural Environment Research Council; Cambridge UK
| | - W. Li
- Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles California USA
| | - L. R. Lyons
- Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles California USA
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40
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Summers D, Ni B, Meredith NP. Timescales for radiation belt electron acceleration and loss due to resonant wave-particle interactions: 2. Evaluation for VLF chorus, ELF hiss, and electromagnetic ion cyclotron waves. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006ja011993] [Citation(s) in RCA: 305] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Danny Summers
- Department of Mathematics and Statistics; Memorial University of Newfoundland; St. John's Newfoundland Canada
| | - Binbin Ni
- Department of Mathematics and Statistics; Memorial University of Newfoundland; St. John's Newfoundland Canada
| | - Nigel P. Meredith
- British Antarctic Survey; Natural Environment Research Council; Cambridge UK
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41
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Bortnik J, Thorne RM, O'Brien TP, Green JC, Strangeway RJ, Shprits YY, Baker DN. Observation of two distinct, rapid loss mechanisms during the 20 November 2003 radiation belt dropout event. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2006ja011802] [Citation(s) in RCA: 161] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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42
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Shprits YY, Thorne RM, Horne RB, Summers D. Bounce-averaged diffusion coefficients for field-aligned chorus waves. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2006ja011725] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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43
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Iles RHA, Meredith NP, Fazakerley AN, Horne RB. Phase space density analysis of the outer radiation belt energetic electron dynamics. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2005ja011206] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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44
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Horne RB, Thorne RM, Shprits YY, Meredith NP, Glauert SA, Smith AJ, Kanekal SG, Baker DN, Engebretson MJ, Posch JL, Spasojevic M, Inan US, Pickett JS, Decreau PME. Wave acceleration of electrons in the Van Allen radiation belts. Nature 2005; 437:227-30. [PMID: 16148927 DOI: 10.1038/nature03939] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2005] [Accepted: 06/10/2005] [Indexed: 11/08/2022]
Abstract
The Van Allen radiation belts are two regions encircling the Earth in which energetic charged particles are trapped inside the Earth's magnetic field. Their properties vary according to solar activity and they represent a hazard to satellites and humans in space. An important challenge has been to explain how the charged particles within these belts are accelerated to very high energies of several million electron volts. Here we show, on the basis of the analysis of a rare event where the outer radiation belt was depleted and then re-formed closer to the Earth, that the long established theory of acceleration by radial diffusion is inadequate; the electrons are accelerated more effectively by electromagnetic waves at frequencies of a few kilohertz. Wave acceleration can increase the electron flux by more than three orders of magnitude over the observed timescale of one to two days, more than sufficient to explain the new radiation belt. Wave acceleration could also be important for Jupiter, Saturn and other astrophysical objects with magnetic fields.
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Affiliation(s)
- Richard B Horne
- British Antarctic Survey, Madingley Road, Cambridge CB3 0ET, UK.
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45
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Thorne RM, O'Brien TP, Shprits YY, Summers D, Horne RB. Timescale for MeV electron microburst loss during geomagnetic storms. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2004ja010882] [Citation(s) in RCA: 266] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- R. M. Thorne
- Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles California USA
| | - T. P. O'Brien
- Space Science Department; The Aerospace Corporation; El Segundo California USA
| | - Y. Y. Shprits
- Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles California USA
| | - D. Summers
- Department of Mathematics and Statistics; Memorial University of Newfoundland; St. John's, Newfoundland Canada
| | - R. B. Horne
- British Antarctic Survey; Natural Environment Research Council; Cambridge UK
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46
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Summers D. Quasi-linear diffusion coefficients for field-aligned electromagnetic waves with applications to the magnetosphere. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2005ja011159] [Citation(s) in RCA: 216] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Danny Summers
- Department of Mathematics and Statistics; Memorial University of Newfoundland; St. John's, Newfoundland Canada
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