1
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Haas B, Shprits YY, Wutzig M, Szabó-Roberts M, García Peñaranda M, Castillo Tibocha AM, Himmelsbach J, Wang D, Miyoshi Y, Kasahara S, Keika K, Yokota S, Shinohara I, Hori T. Global validation of data-assimilative electron ring current nowcast for space weather applications. Sci Rep 2024; 14:2327. [PMID: 38282034 PMCID: PMC10822866 DOI: 10.1038/s41598-024-52187-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 01/13/2024] [Indexed: 01/30/2024] Open
Abstract
The hazardous plasma environment surrounding Earth poses risks to satellites due to internal charging and surface charging effects. Accurate predictions of these risks are crucial for minimizing damage and preparing for system failures of satellites. To forecast the plasma environment, it is essential to know the current state of the system, as the accuracy of the forecast depends on the accuracy of the initial condition of the forecast. In this study, we use data assimilation techniques to combine observational data and model predictions, and present the first global validation of a data-assimilative electron ring current nowcast during a geomagnetic storm. By assimilating measurements from one satellite and validating the results against another satellite in a different magnetic local time sector, we assess the global response and effectiveness of the data assimilation technique for space weather applications. Using this method, we found that the simulation accuracy can be drastically improved at times when observations are available while eliminating almost all of the bias previously present in the model. These findings contribute to the construction of improved operational models in estimating surface charging risks and providing realistic 'source' populations for radiation belt simulations.
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Affiliation(s)
- Bernhard Haas
- GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Potsdam, Germany.
- Institute of Physics and Astronomy, University of Potsdam, Potsdam, Germany.
| | - Yuri Y Shprits
- GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Potsdam, Germany
- Institute of Physics and Astronomy, University of Potsdam, Potsdam, Germany
- Department of the Earth, Planetary and Space Sciences, University of California, Los Angeles, CA, USA
| | - Michael Wutzig
- GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Potsdam, Germany
| | - Mátyás Szabó-Roberts
- GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Potsdam, Germany
| | - Marina García Peñaranda
- GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Potsdam, Germany
- Institute of Physics and Astronomy, University of Potsdam, Potsdam, Germany
| | - Angelica M Castillo Tibocha
- GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Potsdam, Germany
- Institute of Physics and Astronomy, University of Potsdam, Potsdam, Germany
| | - Julia Himmelsbach
- GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Potsdam, Germany
| | - Dedong Wang
- GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Potsdam, Germany
| | | | | | | | | | | | - Tomo Hori
- ISEE, Nagoya University, Nagoya, Japan
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2
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A missing dusk-side loss process in the terrestrial electron ring current. Sci Rep 2023; 13:970. [PMID: 36653461 PMCID: PMC9849215 DOI: 10.1038/s41598-023-28093-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 01/12/2023] [Indexed: 01/19/2023] Open
Abstract
The Earth's magnetic field traps charged particles which are transported longitudinally around Earth, generating a near-circular current, known as the ring current. While the ring current has been measured on the ground and space for many decades, the enhancement of the ring current during geomagnetic storms is still not well understood, due to many processes contributing to its dynamics on different time scales. Here, we show that existing ring current models systematically overestimate electron flux observations of 10-50 keV on the nightside during storm onset. By analyzing electron drift trajectories, we show that this systematic overestimation of flux can be explained through a missing loss process which operates in the pre-midnight sector. Quantifying this loss reveals that the theoretical upper limit of loss has to be reached over a broad region of space in order to reproduce the observations. This missing loss may be attributed to inaccuracies in the parameterization of the loss due to chorus wave interactions, combined with the scattering by electrostatic electron cyclotron harmonic waves which is currently not included in ring current models.
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3
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Mourenas D, Artemyev AV, Zhang X, Angelopoulos V. Extreme Energy Spectra of Relativistic Electron Flux in the Outer Radiation Belt. JOURNAL OF GEOPHYSICAL RESEARCH. SPACE PHYSICS 2022; 127:e2022JA031038. [PMID: 36591600 PMCID: PMC9788025 DOI: 10.1029/2022ja031038] [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: 09/22/2022] [Revised: 11/03/2022] [Accepted: 11/07/2022] [Indexed: 06/17/2023]
Abstract
Electron diffusion by whistler-mode chorus waves is one of the key processes controlling the dynamics of relativistic electron fluxes in the Earth's radiation belts. It is responsible for the acceleration of sub-relativistic electrons injected from the plasma sheet to relativistic energies as well as for their precipitation and loss into the atmosphere. Based on analytical estimates of chorus wave-driven quasi-linear electron energy and pitch-angle diffusion rates, we provide analytical steady-state solutions to the corresponding Fokker-Planck equation for the relativistic electron distribution and flux. The impact on these steady-state solutions of additional electromagnetic ion cyclotron waves, and of ultralow frequency waves are examined. Such steady-state solutions correspond to hard energy spectra at 1-4 MeV, dangerous for satellite electronics, and represent attractors for the system dynamics in the presence of sufficiently strong driving by continuous injections of 10-300 keV electrons. Therefore, these analytical steady-state solutions provide a simple means for estimating the most extreme electron energy spectra potentially encountered in the outer radiation belt, despite the great variability of injections and plasma conditions. These analytical steady-state solutions are compared with numerical simulations based on the full Fokker-Planck equation and with relativistic electron flux spectra measured by satellites during one extreme event and three strong events of high time-integrated geomagnetic activity, demonstrating a good agreement.
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Affiliation(s)
- D. Mourenas
- CEADAMDIFArpajonFrance
- Laboratoire Matière en Conditions ExtrêmesCEAParis‐Saclay UniversityBruyères‐le‐ChâtelFrance
| | - A. V. Artemyev
- Department of Earth, Planetary, and Space SciencesUniversity of CaliforniaLos AngelesCAUSA
| | - X.‐J. Zhang
- Department of Earth, Planetary, and Space SciencesUniversity of CaliforniaLos AngelesCAUSA
- Department of PhysicsUniversity of Texas at DallasRichardsonTXUSA
| | - V. Angelopoulos
- Department of Earth, Planetary, and Space SciencesUniversity of CaliforniaLos AngelesCAUSA
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4
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Mourenas D, Agapitov OV, Artemyev AV, Zhang X. A Climatology of Long-Duration High 2-MeV Electron Flux Periods in the Outer Radiation Belt. JOURNAL OF GEOPHYSICAL RESEARCH. SPACE PHYSICS 2022; 127:e2022JA030661. [PMID: 36247330 PMCID: PMC9541471 DOI: 10.1029/2022ja030661] [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: 05/16/2022] [Revised: 06/29/2022] [Accepted: 07/28/2022] [Indexed: 06/16/2023]
Abstract
Since the advent of the Space Age, the importance of understanding and forecasting relativistic electron fluxes in the Earth's radiation belts has been steadily growing due to the threat that such particles pose to satellite electronics. Here, we provide a model of long-duration periods of high time-integrated 2-MeV electron flux deep inside the outer radiation belt, based on the significant correlation obtained in 2001-2017 between time-integrated electron flux measured by satellites and a measure of the preceding time-integrated homogenized aa H geomagnetic index. We show that this correlation is likely due to a stronger cumulative chorus wave-driven acceleration of relativistic electrons and a stronger cumulative inward radial diffusion of such electrons during periods of higher time-integrated geomagnetic activity. Return levels of 2-MeV electron flux are provided based on Extreme Value analysis of time-integrated geomagnetic activity over 1868-2017, in rough agreement with estimates based on 20-year data sets of measured flux. A high correlation is also found between our measure of time-integrated geomagnetic activity averaged over each solar cycle and averaged sunspot numbers, potentially paving the way for forecasts of time-integrated relativistic electron flux during future solar cycles based on predictions of solar activity.
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Affiliation(s)
- D. Mourenas
- CEADAMDIFArpajonFrance
- Laboratoire Matière en Conditions ExtrêmesParis‐Saclay UniversityCEABruyères‐le‐ChâtelFrance
| | - O. V. Agapitov
- Space Sciences LaboratoryUniversity of CaliforniaBerkeleyCAUSA
| | - A. V. Artemyev
- Department of Earth, Planetary, and Space SciencesUniversity of CaliforniaLos AngelesCAUSA
| | - X.‐J. Zhang
- Department of Earth, Planetary, and Space SciencesUniversity of CaliforniaLos AngelesCAUSA
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5
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Staples FA, Kellerman A, Murphy KR, Rae IJ, Sandhu JK, Forsyth C. Resolving Magnetopause Shadowing Using Multimission Measurements of Phase Space Density. JOURNAL OF GEOPHYSICAL RESEARCH. SPACE PHYSICS 2022; 127:e2021JA029298. [PMID: 35864842 PMCID: PMC9286781 DOI: 10.1029/2021ja029298] [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: 03/01/2021] [Revised: 12/21/2021] [Accepted: 01/10/2022] [Indexed: 06/15/2023]
Abstract
Loss mechanisms act independently or in unison to drive rapid loss of electrons in the radiation belts. Electrons may be lost by precipitation into the Earth's atmosphere, or through the magnetopause into interplanetary space-a process known as magnetopause shadowing. While magnetopause shadowing is known to produce dropouts in electron flux, it is unclear if shadowing continues to remove particles in tandem with electron acceleration processes, limiting the overall flux increase. We investigated the contribution of shadowing to overall radiation belt fluxes throughout a geomagnetic storm starting on the 7 September 2017. We use new, multimission phase space density calculations to decipher electron dynamics during each storm phase and identify features of magnetopause shadowing during both the net-loss and the net-acceleration storm phases on sub-hour time scales. We also highlight two distinct types of shadowing; "direct," where electrons are lost as their orbit intersects the magnetopause, and "indirect," where electrons are lost through ULF wave driven radial transport toward the magnetopause boundary.
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Affiliation(s)
- F. A. Staples
- Mullard Space Science LaboratoryUniversity College LondonLondonUK
| | - A. Kellerman
- Department of Earth, Planetary, and Space SciencesUniversity of CaliforniaLos AngelesCAUSA
| | | | - I. J. Rae
- Northumbria UniversityNewcastle upon TyneUK
| | | | - C. Forsyth
- Mullard Space Science LaboratoryUniversity College LondonLondonUK
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6
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Wilson LB, Brosius AL, Gopalswamy N, Nieves‐Chinchilla T, Szabo A, Hurley K, Phan T, Kasper JC, Lugaz N, Richardson IG, Chen CHK, Verscharen D, Wicks RT, TenBarge JM. A Quarter Century of Wind Spacecraft Discoveries. REVIEWS OF GEOPHYSICS (WASHINGTON, D.C. : 1985) 2021; 59:e2020RG000714. [PMCID: PMC9285980 DOI: 10.1029/2020rg000714] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 01/29/2021] [Accepted: 03/05/2021] [Indexed: 06/13/2023]
Abstract
The Wind spacecraft, launched on November 1, 1994, is a critical element in NASA’s Heliophysics System Observatory (HSO)—a fleet of spacecraft created to understand the dynamics of the Sun‐Earth system. The combination of its longevity (>25 years in service), its diverse complement of instrumentation, and high resolution and accurate measurements has led to it becoming the “standard candle” of solar wind measurements. Wind has over 55 selectable public data products with over ∼1,100 total data variables (including OMNI data products) on SPDF/CDAWeb alone. These data have led to paradigm shifting results in studies of statistical solar wind trends, magnetic reconnection, large‐scale solar wind structures, kinetic physics, electromagnetic turbulence, the Van Allen radiation belts, coronal mass ejection topology, interplanetary and interstellar dust, the lunar wake, solar radio bursts, solar energetic particles, and extreme astrophysical phenomena such as gamma‐ray bursts. This review introduces the mission and instrument suites then discusses examples of the contributions by Wind to these scientific topics that emphasize its importance to both the fields of heliophysics and astrophysics. Wind has made seminal advances to the fields of astrophysics, turbulence, kinetic physics, magnetic reconnection, and the radiation belts Wind pioneered the study of the source and evolution of solar radio emissions below 15 MHz Wind revolutionized our understanding of coronal mass ejections, their internal magnetic structure, and evolution
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Affiliation(s)
- Lynn B. Wilson
- NASA Goddard Space Flight CenterHeliophysics Science DivisionGreenbeltMDUSA
| | - Alexandra L. Brosius
- NASA Goddard Space Flight CenterHeliophysics Science DivisionGreenbeltMDUSA
- Department of Meteorology and Atmospheric ScienceThe Pennsylvania State UniversityUniversity ParkPAUSA
| | | | | | - Adam Szabo
- NASA Goddard Space Flight CenterHeliophysics Science DivisionGreenbeltMDUSA
| | - Kevin Hurley
- Space Sciences LaboratoryUniversity of CaliforniaBerkeleyCAUSA
| | - Tai Phan
- Space Sciences LaboratoryUniversity of CaliforniaBerkeleyCAUSA
| | - Justin C. Kasper
- School of Climate and Space Sciences and EngineeringUniversity of MichiganAnn ArborAnn ArborMIUSA
| | - Noé Lugaz
- Space Science CenterInstitute for the Study of EarthOceans, and SpaceUniversity of New HampshireDurhamNHUSA
- Department of PhysicsUniversity of New HampshireDurhamNHUSA
| | - Ian G. Richardson
- NASA Goddard Space Flight CenterHeliophysics Science DivisionGreenbeltMDUSA
- Department of AstronomyUniversity of MarylandCollege ParkMDUSA
| | | | - Daniel Verscharen
- Space Science CenterInstitute for the Study of EarthOceans, and SpaceUniversity of New HampshireDurhamNHUSA
- Mullard Space Science LaboratoryUniversity College LondonSurreyUK
| | - Robert T. Wicks
- Department of MathematicsPhysics and Electrical EngineeringNorthumbria University: Newcastle upon TyneTyne and WearUK
| | - Jason M. TenBarge
- University of MarylandCollege ParkMDUSA
- Department of Astrophysical SciencesPrinceton UniversityPrincetonNJUSA
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7
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Coexistence of Lightning Generated Whistlers, Hiss and Lower Hybrid Noise Observed by e-POP (SWARM-E)–RRI. ATMOSPHERE 2020. [DOI: 10.3390/atmos11020177] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Whistler mode waves play a major role in regulating the lifetime of trapped electrons in the Earth’s radiation belts. Specifically, interaction with whistler mode hiss waves is one of the mechanisms that maintains the slot region between the inner and outer radiation belts. The generation mechanism of hiss is a topic still under debate with at least three prominent theories present in the literature. Lightning generated whistlers in their ducted or non-ducted modes are considered to be one of the possible sources of hiss. We present a study of new observations from the Radio Receiver Instrument (RRI) on the Enhanced Polar Outflow Probe (ePOP: also known as SWARM-E). RRI consists of two orthogonal dipole antennas, which enables polarization measurements, when the satellite boresight is parallel to the geomagnetic field. Here we present 105 ePOP - RRI events from 2014–2018, in which lightning whistlers(75) and hiss waves(39) were observed. In more than 50% of those whistler observations, hiss found to co-exist. Moreover, the whistler observations are correlated with observations of wave power at the lower-hybrid resonance. The observations and a whistler mode ray-tracing study suggest that multiple-hop lightning induced whistlers can be a source of hiss and plasma instabilities in the magnetosphere.
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8
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Sano T, Hata M, Kawahito D, Mima K, Sentoku Y. Ultrafast wave-particle energy transfer in the collapse of standing whistler waves. Phys Rev E 2019; 100:053205. [PMID: 31869898 DOI: 10.1103/physreve.100.053205] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Indexed: 06/10/2023]
Abstract
Efficient energy transfer from electromagnetic waves to ions has been demanded to control laboratory plasmas for various applications and could be useful to understand the nature of space and astrophysical plasmas. However, there exists the severe unsolved problem that most of the wave energy is converted quickly to electrons but not to ions. Here, an energy-to-ion conversion process in overdense plasmas associated with whistler waves is investigated by numerical simulations and a theoretical model. Whistler waves propagating along a magnetic field in space and laboratories often form standing waves by the collision of counter-propagating waves or through the reflection. We find that ions in standing whistler waves acquire a large amount of energy directly from the waves over a short time scale comparable to the wave oscillation period. The thermalized ion temperature increases in proportion to the square of the wave amplitude and becomes much higher than the electron temperature in a wide range of wave-plasma conditions. This efficient ion-heating mechanism applies to various plasma phenomena in space physics and fusion energy sciences.
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Affiliation(s)
- Takayoshi Sano
- Institute of Laser Engineering, Osaka University, Suita, Osaka 565-0871, Japan
| | - Masayasu Hata
- Institute of Laser Engineering, Osaka University, Suita, Osaka 565-0871, Japan
| | - Daiki Kawahito
- Center for Energy Research, University of California, San Diego, La Jolla, California 92093-0417, USA
| | - Kunioki Mima
- Institute of Laser Engineering, Osaka University, Suita, Osaka 565-0871, Japan
- The Graduate School for the Creation of New Photonics Industries, Hamamatsu, Shizuoka 431-1202, Japan
| | - Yasuhiko Sentoku
- Institute of Laser Engineering, Osaka University, Suita, Osaka 565-0871, Japan
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9
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Daglis IA, Katsavrias C, Georgiou M. From solar sneezing to killer electrons: outer radiation belt response to solar eruptions. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2019; 377:20180097. [PMID: 31079586 PMCID: PMC6527955 DOI: 10.1098/rsta.2018.0097] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/19/2019] [Indexed: 06/09/2023]
Abstract
Electrons in the outer Van Allen (radiation) belt occasionally reach relativistic energies, turning them into a potential hazard for spacecraft operating in geospace. Such electrons have secured the reputation of satellite killers and play a prominent role in space weather. The flux of these electrons can vary over time scales of years (related to the solar cycle) to minutes (related to sudden storm commencements). Electric fields and plasma waves are the main factors regulating the electron transport, acceleration and loss. Both the fields and the plasma waves are driven directly or indirectly by disturbances originating in the Sun, propagating through interplanetary space and impacting the Earth. This paper reviews our current understanding of the response of outer Van Allen belt electrons to solar eruptions and their interplanetary extensions, i.e. interplanetary coronal mass ejections and high-speed solar wind streams and the associated stream interaction regions. This article is part of the theme issue 'Solar eruptions and their space weather impact'.
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Affiliation(s)
- Ioannis A. Daglis
- Department of Physics, National and Kapodistrian University of Athens, 15487 Athens, Greece
- Institute of Accelerating Systems and Applications, National and Kapodistrian University of Athens, 15487 Athens, Greece
- Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing, National Observatory of Athens, 15236 Penteli, Greece
| | - Christos Katsavrias
- Department of Physics, National and Kapodistrian University of Athens, 15487 Athens, Greece
- Institute of Accelerating Systems and Applications, National and Kapodistrian University of Athens, 15487 Athens, Greece
| | - Marina Georgiou
- Mullard Space Science Laboratory, Department of Space and Climate Physics, University College London, Dorking RH5 6NT, UK
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10
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An X, Li J, Bortnik J, Decyk V, Kletzing C, Hospodarsky G. Unified View of Nonlinear Wave Structures Associated with Whistler-Mode Chorus. PHYSICAL REVIEW LETTERS 2019; 122:045101. [PMID: 30768310 DOI: 10.1103/physrevlett.122.045101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Indexed: 06/09/2023]
Abstract
A range of nonlinear wave structures, including Langmuir waves, unipolar electric fields, and bipolar electric fields, are often observed in association with whistler-mode chorus waves in near-Earth space. We demonstrate that the three seemingly different nonlinear wave structures originate from the same nonlinear electron trapping process by whistler-mode chorus waves. The ratio of the Landau resonant velocity to the electron thermal velocity controls the type of nonlinear wave structures that will be generated.
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Affiliation(s)
- Xin An
- Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, California 90095, USA
| | - Jinxing Li
- Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, California 90095, USA
| | - Jacob Bortnik
- Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, California 90095, USA
| | - Viktor Decyk
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
| | - Craig Kletzing
- Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242, USA
| | - George Hospodarsky
- Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242, USA
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11
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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. JOURNAL OF GEOPHYSICAL RESEARCH. SPACE PHYSICS 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] [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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12
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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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13
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Antonova EE, Stepanova MV, Moya PS, Pinto VA, Vovchenko VV, Ovchinnikov IL, Sotnikov NV. Processes in auroral oval and outer electron radiation belt. EARTH, PLANETS, AND SPACE : EPS 2018; 70:127. [PMID: 30956530 PMCID: PMC6428230 DOI: 10.1186/s40623-018-0898-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Accepted: 08/01/2018] [Indexed: 06/09/2023]
Abstract
We have analyzed the role of auroral processes in the formation of the outer radiation belt, considering that the main part of the auroral oval maps to the outer part of the ring current, instead of the plasma sheet as is commonly postulated. In this approach, the outer ring current is the region where transverse magnetospheric currents close inside the magnetosphere. Specifically, we analyzed the role of magnetospheric substorms in the appearance of relativistic electrons in the outer radiation belt. We present experimental evidence that the presence of substorms during a geomagnetic storm recovery phase is, in fact, very important for the appearance of a new radiation belt during this phase. We discuss the possible role of adiabatic acceleration of relativistic electrons during storm recovery phase and show that this mechanism may accelerate the relativistic electrons by more than one order of magnitude.
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Affiliation(s)
- Elizaveta E. Antonova
- Skobeltsyn Institute of Nuclear Physics and Space Research Institute RAS, Lomonosov Moscow State University, Moscow, Russia
| | - Marina V. Stepanova
- Departamento de Fisica, Universidad de Santiago de Chile (USACH), Santiago, Chile
| | - Pablo S. Moya
- Departamento de Fisica, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Victor A. Pinto
- Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, USA
| | | | - Ilya L. Ovchinnikov
- Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow, Russia
| | - Nikita V. Sotnikov
- Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow, Russia
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14
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Forsyth C, Rae IJ, Murphy KR, Freeman MP, Huang C, Spence HE, Boyd AJ, Coxon JC, Jackman CM, Kalmoni NME, Watt CEJ. What effect do substorms have on the content of the radiation belts? JOURNAL OF GEOPHYSICAL RESEARCH. SPACE PHYSICS 2016; 121:6292-6306. [PMID: 27656336 PMCID: PMC5014235 DOI: 10.1002/2016ja022620] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 06/06/2016] [Accepted: 06/08/2016] [Indexed: 06/01/2023]
Abstract
Substorms are fundamental and dynamic processes in the magnetosphere, converting captured solar wind magnetic energy into plasma energy. These substorms have been suggested to be a key driver of energetic electron enhancements in the outer radiation belts. Substorms inject a keV "seed" population into the inner magnetosphere which is subsequently energized through wave-particle interactions up to relativistic energies; however, the extent to which substorms enhance the radiation belts, either directly or indirectly, has never before been quantified. In this study, we examine increases and decreases in the total radiation belt electron content (TRBEC) following substorms and geomagnetically quiet intervals. Our results show that the radiation belts are inherently lossy, shown by a negative median change in TRBEC at all intervals following substorms and quiet intervals. However, there are up to 3 times as many increases in TRBEC following substorm intervals. There is a lag of 1-3 days between the substorm or quiet intervals and their greatest effect on radiation belt content, shown in the difference between the occurrence of increases and losses in TRBEC following substorms and quiet intervals, the mean change in TRBEC following substorms or quiet intervals, and the cross correlation between SuperMAG AL (SML) and TRBEC. However, there is a statistically significant effect on the occurrence of increases and decreases in TRBEC up to a lag of 6 days. Increases in radiation belt content show a significant correlation with SML and SYM-H, but decreases in the radiation belt show no apparent link with magnetospheric activity levels.
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Affiliation(s)
- C. Forsyth
- Mullard Space Science LaboratoryUniversity College LondonDorkingUK
| | - I. J. Rae
- Mullard Space Science LaboratoryUniversity College LondonDorkingUK
| | - K. R. Murphy
- NASA Goddard Space Flight CenterGreenbeltMarylandUSA
| | | | - C.‐L. Huang
- Space Science CenterUniversity of New HampshireDurhamNew HampshireUSA
| | - H. E. Spence
- Space Science CenterUniversity of New HampshireDurhamNew HampshireUSA
| | - A. J. Boyd
- Space Science CenterUniversity of New HampshireDurhamNew HampshireUSA
- New Mexico ConsortiumLos AlamosNew MexicoUSA
| | - J. C. Coxon
- School of Physics and AstronomyUniversity of SouthamptonSouthamptonUK
| | - C. M. Jackman
- School of Physics and AstronomyUniversity of SouthamptonSouthamptonUK
| | - N. M. E. Kalmoni
- Mullard Space Science LaboratoryUniversity College LondonDorkingUK
| | - C. E. J. Watt
- Department of MeteorologyUniversity of ReadingReadingUK
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15
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Su Z, Zhu H, Xiao F, Zong QG, Zhou XZ, Zheng H, Wang Y, Wang S, Hao YX, Gao Z, He Z, Baker DN, Spence HE, Reeves GD, Blake JB, Wygant JR. Ultra-low-frequency wave-driven diffusion of radiation belt relativistic electrons. Nat Commun 2015; 6:10096. [PMID: 26690250 PMCID: PMC4703845 DOI: 10.1038/ncomms10096] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 11/03/2015] [Indexed: 11/15/2022] Open
Abstract
Van Allen radiation belts are typically two zones of energetic particles encircling the Earth separated by the slot region. How the outer radiation belt electrons are accelerated to relativistic energies remains an unanswered question. Recent studies have presented compelling evidence for the local acceleration by very-low-frequency (VLF) chorus waves. However, there has been a competing theory to the local acceleration, radial diffusion by ultra-low-frequency (ULF) waves, whose importance has not yet been determined definitively. Here we report a unique radiation belt event with intense ULF waves but no detectable VLF chorus waves. Our results demonstrate that the ULF waves moved the inner edge of the outer radiation belt earthward 0.3 Earth radii and enhanced the relativistic electron fluxes by up to one order of magnitude near the slot region within about 10 h, providing strong evidence for the radial diffusion of radiation belt relativistic electrons.
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Affiliation(s)
- Zhenpeng Su
- CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
- Collaborative Innovation Center of Astronautical Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Hui Zhu
- CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
- Mengcheng National Geophysical Observatory, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Fuliang Xiao
- School of Physics and Electronic Sciences, Changsha University of Science and Technology, Changsha Hunan 410004, China
| | - Q.-G. Zong
- Institute of Space Physics and Applied Technology, Peking University, Beijing 100871, China
| | - X.-Z. Zhou
- Institute of Space Physics and Applied Technology, Peking University, Beijing 100871, China
| | - Huinan Zheng
- CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
- Collaborative Innovation Center of Astronautical Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yuming Wang
- CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
- Collaborative Innovation Center of Astronautical Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Shui Wang
- CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
- Collaborative Innovation Center of Astronautical Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Y.-X. Hao
- Institute of Space Physics and Applied Technology, Peking University, Beijing 100871, China
| | - Zhonglei Gao
- CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
- Mengcheng National Geophysical Observatory, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Zhaoguo He
- Harbin Institute of Technology Shenzhen Graduate School, Shenzhen, Guangdong 518055, China
| | - D. N. Baker
- Laboratory for Atmospheric and Space Physics, University of Colorado Boulder, Boulder, Colorado 80303-7814, USA
| | - H. E. Spence
- Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, New Hampshire 03824-3525, USA
| | - G. D. Reeves
- Space Science and Applications Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87544, USA
| | - J. B. Blake
- The Aerospace Corporation, Los Angeles, California 90245-4609, USA
| | - J. R. Wygant
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
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16
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Xiao F, Yang C, Su Z, Zhou Q, He Z, He Y, Baker DN, Spence HE, Funsten HO, Blake JB. Wave-driven butterfly distribution of Van Allen belt relativistic electrons. Nat Commun 2015; 6:8590. [PMID: 26436770 PMCID: PMC4600758 DOI: 10.1038/ncomms9590] [Citation(s) in RCA: 123] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 09/09/2015] [Indexed: 11/09/2022] Open
Abstract
Van Allen radiation belts consist of relativistic electrons trapped by Earth's magnetic field. Trapped electrons often drift azimuthally around Earth and display a butterfly pitch angle distribution of a minimum at 90° further out than geostationary orbit. This is usually attributed to drift shell splitting resulting from day-night asymmetry in Earth's magnetic field. However, direct observation of a butterfly distribution well inside of geostationary orbit and the origin of this phenomenon have not been provided so far. Here we report high-resolution observation that a unusual butterfly pitch angle distribution of relativistic electrons occurred within 5 Earth radii during the 28 June 2013 geomagnetic storm. Simulation results show that combined acceleration by chorus and magnetosonic waves can successfully explain the electron flux evolution both in the energy and butterfly pitch angle distribution. The current provides a great support for the mechanism of wave-driven butterfly distribution of relativistic electrons.
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Affiliation(s)
- Fuliang Xiao
- School of Physics and Electronic Sciences, Changsha University of Science and Technology, 2nd Section, South Wanjiali Road #960, Yuhua District, Changsha, Hunan 410004, China
| | - Chang Yang
- School of Physics and Electronic Sciences, Changsha University of Science and Technology, 2nd Section, South Wanjiali Road #960, Yuhua District, Changsha, Hunan 410004, China
| | - Zhenpeng Su
- Chinese Academy of Sciences Key Laboratory for Basic Plasma Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Qinghua Zhou
- School of Physics and Electronic Sciences, Changsha University of Science and Technology, 2nd Section, South Wanjiali Road #960, Yuhua District, Changsha, Hunan 410004, China
| | - Zhaoguo He
- Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100190, China
| | - Yihua He
- School of Physics and Electronic Sciences, Changsha University of Science and Technology, 2nd Section, South Wanjiali Road #960, Yuhua District, Changsha, Hunan 410004, China
| | - D. N. Baker
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80303, USA
| | - H. E. Spence
- Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, New Hampshire 03824-3525, USA
| | - H. O. Funsten
- ISR Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - J. B. Blake
- The Aerospace Corporation, Los Angeles, California 90245-4609, USA
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17
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Dai L, Wang C, Duan S, He Z, Wygant JR, Cattell CA, Tao X, Su Z, Kletzing C, Baker DN, Li X, Malaspina D, Blake JB, Fennell J, Claudepierre S, Turner DL, Reeves GD, Funsten HO, Spence HE, Angelopoulos V, Fruehauff D, Chen L, Thaller S, Breneman A, Tang X. Near-Earth injection of MeV electrons associated with intense dipolarization electric fields: Van Allen Probes observations. GEOPHYSICAL RESEARCH LETTERS 2015; 42:6170-6179. [PMID: 27656009 PMCID: PMC5014237 DOI: 10.1002/2015gl064955] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 07/15/2015] [Accepted: 07/16/2015] [Indexed: 05/17/2023]
Abstract
Substorms generally inject tens to hundreds of keV electrons, but intense substorm electric fields have been shown to inject MeV electrons as well. An intriguing question is whether such MeVelectron injections can populate the outer radiation belt. Here we present observations of a substorm injection of MeV electrons into the inner magnetosphere. In the premidnight sector at L ∼ 5.5, Van Allen Probes (Radiation Belt Storm Probes)-A observed a large dipolarization electric field (50 mV/m) over ∼40 s and a dispersionless injection of electrons up to ∼3 MeV. Pitch angle observations indicated betatron acceleration of MeV electrons at the dipolarization front. Corresponding signals of MeV electron injection were observed at LANL-GEO, THEMIS-D, and GOES at geosynchronous altitude. Through a series of dipolarizations, the injections increased the MeV electron phase space density by 1 order of magnitude in less than 3 h in the outer radiation belt (L > 4.8). Our observations provide evidence that deep injections can supply significant MeV electrons.
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Affiliation(s)
- Lei Dai
- State Key Laboratory of Space Weather, National Space Science Center Chinese Academy of Sciences Beijing China; School of Physics and Astronomy University of Minnesota, Twin Cities Minneapolis Minnesota USA
| | - Chi Wang
- State Key Laboratory of Space Weather, National Space Science Center Chinese Academy of Sciences Beijing China
| | - Suping Duan
- State Key Laboratory of Space Weather, National Space Science Center Chinese Academy of Sciences Beijing China
| | - Zhaohai He
- State Key Laboratory of Space Weather, National Space Science Center Chinese Academy of Sciences Beijing China
| | - John R Wygant
- School of Physics and Astronomy University of Minnesota, Twin Cities Minneapolis Minnesota USA
| | - Cynthia A Cattell
- School of Physics and Astronomy University of Minnesota, Twin Cities Minneapolis Minnesota USA
| | - Xin Tao
- Department of Geophysics and Planetary Sciences University of Science and Technology of China Hefei China
| | - Zhenpeng Su
- Department of Geophysics and Planetary Sciences University of Science and Technology of China Hefei China
| | - Craig Kletzing
- Department of Physics and Astronomy University of Iowa Iowa City Iowa USA
| | - Daniel N Baker
- Laboratory for Atmospheric and Space Physics University of Colorado Boulder Boulder Colorado USA
| | - Xinlin Li
- Laboratory for Atmospheric and Space Physics University of Colorado Boulder Boulder Colorado USA
| | - David Malaspina
- Laboratory for Atmospheric and Space Physics University of Colorado Boulder Boulder Colorado USA
| | - J Bernard Blake
- Space Sciences Department The Aerospace Corporation Los Angeles California USA
| | - Joseph Fennell
- Space Sciences Department The Aerospace Corporation Los Angeles California USA
| | - Seth Claudepierre
- Space Sciences Department The Aerospace Corporation Los Angeles California USA
| | - Drew L Turner
- Space Sciences Department The Aerospace Corporation Los Angeles California USA
| | | | | | - Harlan E Spence
- Department of Physics Institute for Earth, Oceans and Space University of New Hampshire Durham New Hampshire USA
| | - Vassilis Angelopoulos
- Department of Earth, Planetary and Space Sciences and Institute of Geophysics and Planetary Physics University of California Los Angeles California USA
| | - Dennis Fruehauff
- Institute of Geophysics and extraterrestrial Physics Braunschweig University of Technology Braunschweig Germany
| | - Lunjin Chen
- Department of Physics University Of Texas at Dallas Richardson Texas USA
| | - Scott Thaller
- School of Physics and Astronomy University of Minnesota, Twin Cities Minneapolis Minnesota USA
| | - Aaron Breneman
- School of Physics and Astronomy University of Minnesota, Twin Cities Minneapolis Minnesota USA
| | - Xiangwei Tang
- School of Physics and Astronomy University of Minnesota, Twin Cities Minneapolis Minnesota USA
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18
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Van Compernolle B, Bortnik J, Pribyl P, Gekelman W, Nakamoto M, Tao X, Thorne RM. Direct detection of resonant electron pitch angle scattering by whistler waves in a laboratory plasma. PHYSICAL REVIEW LETTERS 2014; 112:145006. [PMID: 24765981 DOI: 10.1103/physrevlett.112.145006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Indexed: 06/03/2023]
Abstract
Resonant interactions between energetic electrons and whistler mode waves are an essential ingredient in the space environment, and in particular in controlling the dynamic variability of Earth's natural radiation belts, which is a topic of extreme interest at the moment. Although the theory describing resonant wave-particle interaction has been present for several decades, it has not been hitherto tested in a controlled laboratory setting. In the present Letter we report on the first laboratory experiment to directly detect resonant pitch angle scattering of energetic (∼keV) electrons due to whistler mode waves. We show that the whistler mode wave deflects energetic electrons at precisely the predicted resonant energy, and that varying both the maximum beam energy, and the wave frequency, alters the energetic electron beam very close to the resonant energy.
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Affiliation(s)
- B Van Compernolle
- Department of Physics, University of California, Los Angeles, California 90095, USA
| | - J Bortnik
- Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, California 90095, USA
| | - P Pribyl
- Department of Physics, University of California, Los Angeles, California 90095, USA
| | - W Gekelman
- Department of Physics, University of California, Los Angeles, California 90095, USA
| | - M Nakamoto
- Department of Physics, University of California, Los Angeles, California 90095, USA
| | - X Tao
- Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, California 90095, USA
| | - R M Thorne
- Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, California 90095, USA
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19
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Ozeke LG, Mann IR, Murphy KR, Jonathan Rae I, Milling DK. Analytic expressions for ULF wave radiation belt radial diffusion coefficients. JOURNAL OF GEOPHYSICAL RESEARCH. SPACE PHYSICS 2014; 119:1587-1605. [PMID: 26167440 PMCID: PMC4497482 DOI: 10.1002/2013ja019204] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 01/23/2014] [Accepted: 02/01/2014] [Indexed: 05/28/2023]
Abstract
We present analytic expressions for ULF wave-derived radiation belt radial diffusion coefficients, as a function of L and Kp, which can easily be incorporated into global radiation belt transport models. The diffusion coefficients are derived from statistical representations of ULF wave power, electric field power mapped from ground magnetometer data, and compressional magnetic field power from in situ measurements. We show that the overall electric and magnetic diffusion coefficients are to a good approximation both independent of energy. We present example 1-D radial diffusion results from simulations driven by CRRES-observed time-dependent energy spectra at the outer boundary, under the action of radial diffusion driven by the new ULF wave radial diffusion coefficients and with empirical chorus wave loss terms (as a function of energy, Kp and L). There is excellent agreement between the differential flux produced by the 1-D, Kp-driven, radial diffusion model and CRRES observations of differential electron flux at 0.976 MeV-even though the model does not include the effects of local internal acceleration sources. Our results highlight not only the importance of correct specification of radial diffusion coefficients for developing accurate models but also show significant promise for belt specification based on relatively simple models driven by solar wind parameters such as solar wind speed or geomagnetic indices such as Kp. KEY POINTS Analytic expressions for the radial diffusion coefficients are presentedThe coefficients do not dependent on energy or wave m valueThe electric field diffusion coefficient dominates over the magnetic.
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Affiliation(s)
- Louis G Ozeke
- Department of Physics, University of AlbertaEdmonton, Alberta, Canada
| | - Ian R Mann
- Department of Physics, University of AlbertaEdmonton, Alberta, Canada
| | - Kyle R Murphy
- Department of Physics, University of AlbertaEdmonton, Alberta, Canada
| | - I Jonathan Rae
- Department of Physics, University of AlbertaEdmonton, Alberta, Canada
- Mullard Space Science LaboratoryDorking, UK
| | - David K Milling
- Department of Physics, University of AlbertaEdmonton, Alberta, Canada
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20
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Meredith NP, Horne RB, Li W, Thorne RM, Sicard-Piet A. Global model of low-frequency chorus ( fLHR< f<0.1 fce) from multiple satellite observations. GEOPHYSICAL RESEARCH LETTERS 2014; 41:280-286. [PMID: 25821274 PMCID: PMC4373175 DOI: 10.1002/2013gl059050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 01/08/2014] [Indexed: 05/28/2023]
Abstract
Whistler mode chorus is an important magnetospheric emission, playing a dual role in the acceleration and loss of relativistic electrons in the Earth's outer radiation belt. Chorus is typically generated in the equatorial region in the frequency range 0.1-0.8 fce, where fce is the local electron gyrofrequency. However, as the waves propagate to higher latitudes, significant wave power can occur at frequencies below 0.1fce. Since this wave power is largely omitted in current radiation belt models, we construct a global model of low-frequency chorus, fLHR KEY POINTS Strong chorus waves can extend below 0.1 times local electron gyrofrequencyLow frequency chorus strongest at mid-latitudes in pre-noon sector for L*=4 to 8Low frequency chorus should be included in radiation belt models.
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Affiliation(s)
- Nigel P Meredith
- British Antarctic Survey, Natural Environment Research Council Cambridge, England
| | - Richard B Horne
- British Antarctic Survey, Natural Environment Research Council Cambridge, England
| | - Wen Li
- Department of Atmospheric and Oceanic Sciences, University of California Los Angeles, California, USA
| | - Richard M Thorne
- Department of Atmospheric and Oceanic Sciences, University of California Los Angeles, California, USA
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21
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Rapid local acceleration of relativistic radiation-belt electrons by magnetospheric chorus. Nature 2014; 504:411-4. [PMID: 24352287 DOI: 10.1038/nature12889] [Citation(s) in RCA: 517] [Impact Index Per Article: 51.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Accepted: 11/18/2013] [Indexed: 11/09/2022]
Abstract
Recent analysis of satellite data obtained during the 9 October 2012 geomagnetic storm identified the development of peaks in electron phase space density, which are compelling evidence for local electron acceleration in the heart of the outer radiation belt, but are inconsistent with acceleration by inward radial diffusive transport. However, the precise physical mechanism responsible for the acceleration on 9 October was not identified. Previous modelling has indicated that a magnetospheric electromagnetic emission known as chorus could be a potential candidate for local electron acceleration, but a definitive resolution of the importance of chorus for radiation-belt acceleration was not possible because of limitations in the energy range and resolution of previous electron observations and the lack of a dynamic global wave model. Here we report high-resolution electron observations obtained during the 9 October storm and demonstrate, using a two-dimensional simulation performed with a recently developed time-varying data-driven model, that chorus scattering explains the temporal evolution of both the energy and angular distribution of the observed relativistic electron flux increase. Our detailed modelling demonstrates the remarkable efficiency of wave acceleration in the Earth's outer radiation belt, and the results presented have potential application to Jupiter, Saturn and other magnetized astrophysical objects.
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22
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Reeves GD, Spence HE, Henderson MG, Morley SK, Friedel RHW, Funsten HO, Baker DN, Kanekal SG, Blake JB, Fennell JF, Claudepierre SG, Thorne RM, Turner DL, Kletzing CA, Kurth WS, Larsen BA, Niehof JT. Electron acceleration in the heart of the Van Allen radiation belts. Science 2013; 341:991-4. [PMID: 23887876 DOI: 10.1126/science.1237743] [Citation(s) in RCA: 403] [Impact Index Per Article: 36.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The Van Allen radiation belts contain ultrarelativistic electrons trapped in Earth's magnetic field. Since their discovery in 1958, a fundamental unanswered question has been how electrons can be accelerated to such high energies. Two classes of processes have been proposed: transport and acceleration of electrons from a source population located outside the radiation belts (radial acceleration) or acceleration of lower-energy electrons to relativistic energies in situ in the heart of the radiation belts (local acceleration). We report measurements from NASA's Van Allen Radiation Belt Storm Probes that clearly distinguish between the two types of acceleration. The observed radial profiles of phase space density are characteristic of local acceleration in the heart of the radiation belts and are inconsistent with a predominantly radial acceleration process.
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Affiliation(s)
- G D Reeves
- Space Science and Applications Group, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
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23
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Baker DN, Kanekal SG, Hoxie VC, Henderson MG, Li X, Spence HE, Elkington SR, Friedel RHW, Goldstein J, Hudson MK, Reeves GD, Thorne RM, Kletzing CA, Claudepierre SG. A long-lived relativistic electron storage ring embedded in Earth's outer Van Allen belt. Science 2013; 340:186-90. [PMID: 23450000 DOI: 10.1126/science.1233518] [Citation(s) in RCA: 189] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Since their discovery more than 50 years ago, Earth's Van Allen radiation belts have been considered to consist of two distinct zones of trapped, highly energetic charged particles. The outer zone is composed predominantly of megaelectron volt (MeV) electrons that wax and wane in intensity on time scales ranging from hours to days, depending primarily on external forcing by the solar wind. The spatially separated inner zone is composed of commingled high-energy electrons and very energetic positive ions (mostly protons), the latter being stable in intensity levels over years to decades. In situ energy-specific and temporally resolved spacecraft observations reveal an isolated third ring, or torus, of high-energy (>2 MeV) electrons that formed on 2 September 2012 and persisted largely unchanged in the geocentric radial range of 3.0 to ~3.5 Earth radii for more than 4 weeks before being disrupted (and virtually annihilated) by a powerful interplanetary shock wave passage.
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Affiliation(s)
- D N Baker
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO, USA.
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24
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Gannon JL, Elkington SR, Onsager TG. Uncovering the nonadiabatic response of geosynchronous electrons to geomagnetic disturbance. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2012ja017543] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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25
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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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26
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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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27
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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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28
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Bunch NL, Spasojevic M, Shprits YY. Off-equatorial chorus occurrence and wave amplitude distributions as observed by the Polar Plasma Wave Instrument. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011ja017228] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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29
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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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30
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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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31
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Borovsky JE, Cayton TE. Entropy mapping of the outer electron radiation belt between the magnetotail and geosynchronous orbit. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011ja016470] [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)
- Joseph E. Borovsky
- Los Alamos National Laboratory; Los Alamos New Mexico USA
- Department of Atmospheric Oceanic and Space Science; University of Michigan; Ann Arbor Michigan USA
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32
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Meredith NP, Horne RB, Lam MM, Denton MH, Borovsky JE, Green JC. Energetic electron precipitation during high-speed solar wind stream driven storms. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010ja016293] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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
| | - Mai Mai Lam
- Department of Physics and Astronomy; University of Leicester; Leicester UK
| | | | - Joseph E. Borovsky
- Space Science and Applications; Los Alamos National Laboratory; Los Alamos New Mexico USA
| | - Janet C. Green
- Space Weather Prediction Center; National Oceanic and Atmospheric Administration; Boulder Colorado USA
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33
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Zong Q, Wang Y, Yuan C, Yang B, Wang C, Zhang X. Fast acceleration of “killer” electrons and energetic ions by interplanetary shock stimulated ULF waves in the inner magnetosphere. CHINESE SCIENCE BULLETIN-CHINESE 2011. [DOI: 10.1007/s11434-010-4308-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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34
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Su Z, Xiao F, Zheng H, Wang S. Radiation belt electron dynamics driven by adiabatic transport, radial diffusion, and wave-particle interactions. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010ja016228] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- 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
- State Key Laboratory of Space Weather; Chinese Academy of Sciences; Beijing China
| | - Fuliang Xiao
- School of Physics and Electronic Sciences; Changsha University of Science and Technology; Changsha 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
- State Key Laboratory of Space Weather; Chinese Academy of Sciences; Beijing 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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35
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Ni B, Shprits Y, Hartinger M, Angelopoulos V, Gu X, Larson D. Analysis of radiation belt energetic electron phase space density using THEMIS SST measurements: Cross-satellite calibration and a case study. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010ja016104] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Binbin Ni
- 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
| | - Michael Hartinger
- Institute of Geophysics and Planetary Physics; University of California; Los Angeles California USA
- Department of Earth and Space Sciences; University of California; Los Angeles California USA
| | - Vassilis Angelopoulos
- Institute of Geophysics and Planetary Physics; University of California; Los Angeles California USA
- Department of Earth and Space Sciences; University of California; Los Angeles California USA
| | - Xudong Gu
- Department of Space Physics; Wuhan University; Wuhan, Hubei China
| | - Davin Larson
- Space Sciences Laboratory; University of California; Berkeley California USA
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36
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Chen L, Thorne RM, Jordanova VK, Horne RB. Global simulation of magnetosonic wave instability in the storm time magnetosphere. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2010ja015707] [Citation(s) in RCA: 134] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Lunjin Chen
- Department of Atmospheric Sciences; University of California; Los Angeles California USA
| | - Richard M. Thorne
- Department of Atmospheric Sciences; University of California; Los Angeles California USA
| | | | - Richard B. Horne
- British Antarctic Survey; Natural Environment Research Council; Cambridge UK
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37
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Su Z, Xiao F, Zheng H, Wang S. STEERB: A three-dimensional code for storm-time evolution of electron radiation belt. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009ja015210] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [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
| | - Fuliang Xiao
- School of Physics and Electronic Sciences; Changsha University of Science and Technology; Changsha 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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38
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Clilverd MA, Rodger CJ, Moffat-Griffin T, Spanswick E, Breen P, Menk FW, Grew RS, Hayashi K, Mann IR. Energetic outer radiation belt electron precipitation during recurrent solar activity. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009ja015204] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Mark A. Clilverd
- British Antarctic Survey; Natural Environment Research Council; Cambridge UK
| | - Craig J. Rodger
- Department of Physics; University of Otago; Dunedin New Zealand
| | | | - Emma Spanswick
- Department of Physics and Astronomy; University of Calgary; Calgary Canada
| | - Paul Breen
- British Antarctic Survey; Natural Environment Research Council; Cambridge UK
| | - Frederick W. Menk
- School of Mathematical and Physical Sciences; University of Newcastle; Callaghan Australia
| | - Russell S. Grew
- School of Mathematical and Physical Sciences; University of Newcastle; Callaghan Australia
| | - Kanji Hayashi
- Department of Earth and Planetary Physics; University of Tokyo; Tokyo Japan
| | - Ian R. Mann
- Department of Physics; University of Alberta; Edmonton Canada
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39
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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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40
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Li W, Thorne RM, Nishimura Y, Bortnik J, Angelopoulos V, McFadden JP, Larson DE, Bonnell JW, Le Contel O, Roux A, Auster U. THEMIS analysis of observed equatorial electron distributions responsible for the chorus excitation. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009ja014845] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- W. Li
- Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles California USA
| | - R. M. Thorne
- Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles California USA
| | - Y. Nishimura
- Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles California USA
- Solar-Terrestrial Environment Laboratory; Nagoya University; Nagoya Japan
| | - J. Bortnik
- Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles California USA
| | - V. Angelopoulos
- Institute of Geophysics and Planetary Physics, Department of Earth and Space Sciences; University of California; Los Angeles California USA
| | - J. P. McFadden
- Space Sciences Laboratory; University of California; Berkeley California USA
| | - D. E. Larson
- Space Sciences Laboratory; University of California; Berkeley California USA
| | - J. W. Bonnell
- Space Sciences Laboratory; University of California; Berkeley California USA
| | - O. Le Contel
- Laboratoire de Physique des Plasmas, Ecole Polytechnique; Université Pierre et Marie Curie, Paris 6, CNRS; Vélizy France
| | - A. Roux
- Laboratoire de Physique des Plasmas, Ecole Polytechnique; Université Pierre et Marie Curie, Paris 6, CNRS; Vélizy France
| | - U. Auster
- Institut für Geophysik und extraterrestrische Physik; Technischen Universität Braunschweig; Braunschweig Germany
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41
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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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42
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Jordanova VK, Thorne RM, Li W, Miyoshi Y. Excitation of whistler mode chorus from global ring current simulations. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009ja014810] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [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 Science; University of California; Los Angeles California USA
| | - W. Li
- Department of Atmospheric and Oceanic Science; University of California; Los Angeles California USA
| | - Y. Miyoshi
- Solar-Terrestrial Environment Laboratory; Nagoya University; Nagoya Japan
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43
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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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44
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Rodger CJ, Clilverd MA, Green JC, Lam MM. Use of POES SEM-2 observations to examine radiation belt dynamics and energetic electron precipitation into the atmosphere. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2008ja014023] [Citation(s) in RCA: 181] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Craig J. Rodger
- Department of Physics; University of Otago; Dunedin New Zealand
| | - Mark A. Clilverd
- Physical Sciences Division; British Antarctic Survey; Cambridge UK
| | - Janet C. Green
- Space Weather Prediction Center, NOAA; Boulder Colorado USA
| | - Mai Mai Lam
- Physical Sciences Division; British Antarctic Survey; Cambridge UK
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45
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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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46
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Ni B, Shprits Y, Thorne R, Friedel R, Nagai T. Reanalysis of relativistic radiation belt electron phase space density using multisatellite observations: Sensitivity to empirical magnetic field models. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2009ja014438] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Binbin Ni
- 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
| | - Richard Thorne
- Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles California USA
| | - Reiner Friedel
- Los Alamos National Laboratory; Los Alamos New Mexico USA
| | - Tsugunobu Nagai
- Department of Earth and Planetary Sciences; Tokyo Institute of Technology; Tokyo Japan
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47
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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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48
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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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49
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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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50
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Ni B, Shprits Y, Nagai T, Thorne R, Chen Y, Kondrashov D, Kim HJ. Reanalyses of the radiation belt electron phase space density using nearly equatorial CRRES and polar-orbiting Akebono satellite observations. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008ja013933] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Binbin Ni
- 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
| | - Tsugunobu Nagai
- Department of Earth and Planetary Sciences; Tokyo Institute of Technology; Tokyo Japan
| | - Richard Thorne
- Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles California USA
| | - Yue Chen
- Los Alamos National Laboratory; Los Alamos New Mexico USA
| | - Dmitri Kondrashov
- 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
| | - Hee-jeong Kim
- Department of Atmospheric and Oceanic Sciences; University of California; Los Angeles California USA
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