Biblio

Found 879 results
Journal Article
Authors: Kirby Karen, Artis David, Bushman Stewart, Butler Michael, Conde Rich, et al.
Title: Radiation Belt Storm Probes—Observatory and Environments
Abstract: The National Aeronautics and Space Administration’s (NASA’s) Radiation Belt Storm Probe (RBSP) is an Earth-orbiting mission that launched August 30, 2012, and is the latest science mission in NASA’s Living with a Star Program. The RBSP mission will investigate, characterize and understand the physical dynamics of the radiation belts, as well as the influence of the Sun on the Earth’s environment, by measuring particles, electric and magnetic fields and waves that comprise geospace. The mission is composed of two identically instrumented spinning observatories in an elliptical orbit around earth with 600 km perigee, 30,000 km apogee and 10∘ inclination to provide full sampling of the Van Allen radiation belts. The twin RBSP observatories (recently renamed the Van Allen Probes) wil. . .
Date: 11/2013 Publisher: Space Science Reviews Pages: 59-125 DOI: 10.1007/s11214-012-9949-2 Available at: http://link.springer.com/article/10.1007%2Fs11214-012-9949-2
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Authors: Maurer Richard H., Fretz Kristin, Angert Matthew P., Bort David L., Goldsten John O., et al.
Title: Radiation-Induced Single-Event Effects on the Van Allen Probes Spacecraft
Abstract: Electronic devices on the Van Allen Probes mission have experienced more than a thousand single-event effects (SEE) during the 4.5 years of transit through the inner and outer earth trapped radiation belts. The majority of these SEE have been due to trapped protons determined by the orbit timing and the dose rate response of the engineering radiation monitor. Fault tolerant systems engineering and spacecraft operation have enabled a successful mission to date without a safe mode or spacecraft emergency.
Date: 09/2017 Publisher: IEEE Transactions on Nuclear Science Pages: 2782 - 2793 DOI: 10.1109/TNS.2017.2754878 Available at: http://ieeexplore.ieee.org/document/8047305/http://xplorestaging.ieee.org/ielx7/23/8106918/08047305.pdf?arnumber=8047305
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Authors: Jordanova V K, Tu W., Chen Y., Morley S. K., Panaitescu A.-D., et al.
Title: RAM-SCB simulations of electron transport and plasma wave scattering during the October 2012 “double-dip” storm
Abstract: Mechanisms for electron injection, trapping, and loss in the near-Earth space environment are investigated during the October 2012 “double-dip” storm using our ring current-atmosphere interactions model with self-consistent magnetic field (RAM-SCB). Pitch angle and energy scattering are included for the first time in RAM-SCB using L and magnetic local time (MLT)-dependent event-specific chorus wave models inferred from NOAA Polar-orbiting Operational Environmental Satellites (POES) and Van Allen Probes Electric and Magnetic Field Instrument Suite and Integrated Science observations. The dynamics of the source (approximately tens of keV) and seed (approximately hundreds of keV) populations of the radiation belts simulated with RAM-SCB is compared with Van Allen Probes Magnetic Electron . . .
Date: 09/2016 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA022470 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA022470/abstract
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Authors: Ukhorskiy A Y, Sitnov M I, Merkin V. G., and Artemyev A. V.
Title: Rapid acceleration of protons upstream of earthward propagating dipolarization fronts
Abstract: [1] Transport and acceleration of ions in the magnetotail largely occurs in the form of discrete impulsive events associated with a steep increase of the tail magnetic field normal to the neutral plane (Bz), which are referred to as dipolarization fronts. The goal of this paper is to investigate how protons initially located upstream of earthward moving fronts are accelerated at their encounter. According to our analytical analysis and simplified two-dimensional test-particle simulations of equatorially mirroring particles, there are two regimes of proton acceleration: trapping and quasi-trapping, which are realized depending on whether the front is preceded by a negative depletion in Bz. We then use three-dimensional test-particle simulations to investigate how these acceleration processe. . .
Date: 01/2013 Publisher: Journal of Geophysical Research: Space Physics Pages: 4952–4962, DOI: 10.1002/jgra.50452 Available at: http://doi.wiley.com/10.1002/jgra.50452
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Authors: Yue Chao, Li Wen, Nishimura Yukitoshi, Zong Qiugang, Ma Qianli, et al.
Title: Rapid enhancement of low-energy (<100 eV) ion flux in response to interplanetary shocks based on two Van Allen Probes case studies: Implications for source regions and heating mechanisms
Abstract: Interactions between interplanetary (IP) shocks and the Earth's magnetosphere manifest many important space physics phenomena including low-energy ion flux enhancements and particle acceleration. In order to investigate the mechanisms driving shock-induced enhancement of low-energy ion flux, we have examined two IP shock events that occurred when the Van Allen Probes were located near the equator while ionospheric and ground observations were available around the spacecraft footprints. We have found that, associated with the shock arrival, electromagnetic fields intensified, and low-energy ion fluxes, including H+, He+, and O+, were enhanced dramatically in both the parallel and perpendicular directions. During the 2 October 2013 shock event, both parallel and perpendicular flux enhancemen. . .
Date: 06/2016 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA022808 Available at: http://doi.wiley.com/10.1002/2016JA022808
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Authors: Tang C. L., Xie X. J., Ni B, Su Z. P., Reeves G D, et al.
Title: Rapid Enhancements of the Seed Populations in the Heart of the Earth's Outer Radiation Belt: A Multicase Study
Abstract: To better understand rapid enhancements of the seed populations (hundreds of keV electrons) in the heart of the Earth's outer radiation belt (L* ~ 3.5–5.0) during different geomagnetic activities, we investigate three enhancement events measured by Van Allen Probes in detail. Observations of the fluxes and the pitch angle distributions of energetic electrons are analyzed to determine rapid enhancements of the seed populations. Our study shows that three specified processes associated with substorm electron injections can lead to rapid enhancements of the seed populations, and the electron energy increases up to 342 keV. In the first process, substorm electron injections accompanied by the transient and intense substorm electric fields can directly lead to rapid enhancements of the seed p. . .
Date: 06/2018 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2017JA025142 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2017JA025142
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Authors: Thorne R M, Li W, Ni B, Ma Q, Bortnik J, et al.
Title: Rapid local acceleration of relativistic radiation-belt electrons by magnetospheric chorus
Abstract: Recent analysis of satellite data obtained during the 9 October 2012 geomagnetic storm identified the development of peaks in electron phase space density1, which are compelling evidence for local electron acceleration in the heart of the outer radiation belt2, 3, but are inconsistent with acceleration by inward radial diffusive transport4, 5. 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 acceleration6, 7, 8, 9, 10, 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. . .
Date: 12/2013 Publisher: Nature Pages: 411 - 414 DOI: 10.1038/nature12889 Available at: http://www.nature.com/doifinder/10.1038/nature12889
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Authors: Su Zhenpeng, Gao Zhonglei, Zheng Huinan, Wang Yuming, Wang Shui, et al.
Title: Rapid loss of radiation belt relativistic electrons by EMIC waves
Abstract: How relativistic electrons are lost is an important question surrounding the complex dynamics of the Earth's outer radiation belt. Radial loss to the magnetopause and local loss to the atmosphere are two main competing paradigms. Here, on the basis of the analysis of a radiation belt storm event on 27 February 2014, we present new evidence for the EMIC wave-driven local precipitation loss of relativistic electrons in the heart of the outer radiation belt. During the main phase of this storm, the radial profile of relativistic electron phase space density was quasi-monotonic, qualitatively inconsistent with the prediction of radial loss theory. The local loss at low L-shells was required to prevent the development of phase space density peak resulting from the radial loss process at high L-. . .
Date: 08/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024169 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA024169/full
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Authors: Kurita S., Miyoshi Y, Shiokawa K., Higashio N., Mitani T., et al.
Title: Rapid loss of relativistic electrons by EMIC waves in the outer radiation belt observed by Arase, Van Allen Probes, and the PWING ground stations
Abstract: There has been increasing evidence for pitch angle scattering of relativistic electrons by electromagnetic ion cyclotron (EMIC) waves. Theoretical studies have predicted that the loss time scale of MeV electrons by EMIC waves can be very fast, suggesting that MeV electron fluxes rapidly decrease in association with the EMIC wave activity. This study reports on a unique event of MeV electron loss induced by EMIC waves based on Arase, Van Allen Probes, and ground‐based network observations. Arase observed a signature of MeV electron loss by EMIC waves, and the satellite and ground‐based observations constrained spatial‐temporal variations of the EMIC wave activity during the loss event. Multi‐satellite observation of MeV electron fluxes showed that ~2.5 MeV electron fluxes substantia. . .
Date: 11/2018 Publisher: Geophysical Research Letters DOI: 10.1029/2018GL080262 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL080262
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Authors: Soto-Chavez A. R., Lanzerotti L J, Gerrard A., Kim H., Bortnik J, et al.
Title: RBSPICE measurement of ion loss during the 2015 March storm: Adiabatic response to the geomagnetic field change
Abstract: A strongly energy-dependent ring current ion loss was measured by the RBSPICE instrument on the Van Allen Probes A spacecraft in the local evening sector during the 17 March 2015 geomagnetic storm. The ion loss is found to be energy dependent where only ions with energies measured above ∼ 150 keV have a significant drop in intensity. At these energies the ion dynamics are principally controlled by variations of the geomagnetic field which, during magnetic storms, exhibits large scale variations on timescales from minutes to hours. Here we show that starting from ∼ 19:10 UTC on March 17 the geomagnetic field increased from 220 to 260 nT on a time scale of about an hour as captured by RBSPICE-A close to spacecraft apogee, L = 6.1 and MLT = 21.85 hr. [GSM coordinates X=-4.89, Y=3.00, . . .
Date: 09/2016 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA022512 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA022512/abstract
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Authors: Aseev N.A., and Shprits Y.Y.
Title: Reanalysis of ring current electron phase space densities using Van Allen Probe observations, convection model, and log‐normal Kalman filter
Abstract: Models of ring current electron dynamics unavoidably contain uncertainties in boundary conditions, electric and magnetic fields, electron scattering rates, and plasmapause location. Model errors can accumulate with time and result in significant deviations of model predictions from observations. Data assimilation offers useful tools which can combine physics‐based models and measurements to improve model predictions. In this study, we systematically analyze performance of the Kalman filter applied to a log‐transformed convection model of ring current electrons and Van Allen Probe data. We consider long‐term dynamics of μ = 2.3 MeV/G and K = 0.3 G1/2RE electrons from 1 February 2013 to 16 June 2013. By using synthetic data, we show that the Kalman filter is capable of correcting erro. . .
Date: 04/2019 Publisher: Space Weather DOI: 10.1029/2018SW002110 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018SW002110
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Authors: Aseev N. A., and Shprits Y Y
Title: Reanalysis of Ring Current Electron Phase Space Densities Using Van Allen Probe Observations, Convection Model, and Log‐Normal Kalman Filter
Abstract: Models of ring current electron dynamics unavoidably contain uncertainties in boundary conditions, electric and magnetic fields, electron scattering rates, and plasmapause location. Model errors can accumulate with time and result in significant deviations of model predictions from observations. Data assimilation offers useful tools which can combine physics‐based models and measurements to improve model predictions. In this study, we systematically analyze performance of the Kalman filter applied to a log‐transformed convection model of ring current electrons and Van Allen Probe data. We consider long‐term dynamics of μ = 2.3 MeV/G and K = 0.3 G1/2RE electrons from 1 February 2013 to 16 June 2013. By using synthetic data, we show that the Kalman filter is capable of correcting . . .
Date: 04/2019 Publisher: Space Weather Pages: 619 - 638 DOI: 10.1029/2018SW002110 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018SW002110
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Authors: Kress B T, Hudson M K, and Paral J.
Title: Rebuilding of the Earth's outer electron belt during 8-10 October 2012
Abstract: Geomagnetic storms often include strong magnetospheric convection caused by sustained periods of southward interplanetary magnetic field. During periods of strong convection, the Alfvén layer, which separates the region of sunward convection from closed drift shells, is displaced earthward allowing plasma sheet particles with energies in the hundreds of keV direct access inside of geosynchronous. Subsequent outward motion of the Alfvén boundary and adiabatic energization during storm recovery traps plasma sheet electrons on closed drift shells providing a seed population for the outer radiation belts. In situ observations of the 8–10 October 2012 geomagnetic storm and MHD test particle simulations illustrate the morphology of this process. Data and modeling results support the conclusi. . .
Date: 02/2014 Publisher: Geophysical Research Letters Pages: 749 - 754 DOI: 10.1002/2013GL058588 Available at: http://doi.wiley.com/10.1002/2013GL058588
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Authors: Miyoshi Yoshizumi
Title: Rebuilding process of the outer radiation belt during the 3 November 1993 magnetic storm: NOAA and Exos-D observations
Abstract: Using the data from the NOAA and Exos-D satellites during the 3 November 1993 magnetic storm, the dynamic behavior of electrons with energies from a few tens of kiloelectronvolts to a few and its relation to plasma waves were examined. After the late main phase, relativistic electron flux started to recover from the heart of the outer radiation belt, where the cold plasma density was extremely low, and intense whistler mode chorus emissions were detected. The phase space density showed a peak in the outer belt, and the peak increased gradually. The simulation of the inward radial diffusion process could not reproduce the observed energy spectrum and phase space density variation. On the other hand, the simulated energy diffusion due to the gyroresonant electron-whistler mode wave interacti. . .
Date: 03/2003 Publisher: Journal of Geophysical Research Pages: SMP 3-1–SMP 3-15 DOI: 10.1029/2001JA007542 Available at: http://onlinelibrary.wiley.com/doi/10.1029/2001JA007542/abstract
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Authors: Andreeva Varvara A., and Tsyganenko Nikolai A.
Title: Reconstructing the magnetosphere from data using radial basis functions
Abstract: A new method is proposed to derive from data magnetospheric magnetic field configurations without any a priori assumptions on the geometry of electric currents. The approach utilizes large sets of archived satellite data and uses an advanced technique to represent the field as a sum of toroidal and poloidal parts, whose generating potentials Ψ1 and Ψ2 are expanded into series of radial basis functions (RBF) with their nodes regularly distributed over the 3D modeling domain. The method was tested by reconstructing the inner and high-latitude field within geocentric distances up to 12RE on the basis of magnetometer data of Geotail, Polar, Cluster, THEMIS, and Van Allen space probes, taken during 1995–2015. Four characteristic states of the magnetosphere before and during a disturbance ha. . .
Date: 02/2016 Publisher: Journal of Geophysical Research: Space Physics Pages: n/a - n/a DOI: 10.1002/2015JA022242 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2015JA022242/full
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Authors: Thorne R M, Shprits Y Y, Meredith N P, Horne R B, Li W, et al.
Title: Refilling of the slot region between the inner and outer electron radiation belts during geomagnetic storms
Abstract: [1] Energetic electrons (≥50 keV) are injected into the slot region (2 < L < 4) between the inner and outer radiation belts during the early recovery phase of geomagnetic storms. Enhanced convection from the plasma sheet can account for the storm-time injection at lower energies but does not explain the rapid appearance of higher-energy electrons (≥150 keV). The effectiveness of either radial diffusion (driven by enhanced ULF waves) or local acceleration (during interactions with enhanced whistler mode chorus emissions), as a potential source for refilling the slot at higher energies, is analyzed for observed conditions during the early recovery phase of the 10 October 1990 storm. We demonstrate that local acceleration, driven by observed chorus emissions, can account for the rapid enh. . .
Date: 06/2007 Publisher: Journal of Geophysical Research DOI: 10.1029/2006JA012176 Available at: http://onlinelibrary.wiley.com/doi/10.1029/2006JA012176/abstract
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Title: On the relation between radiation belt electrons and solar wind parameters/geomagnetic indices: Dependence on the first adiabatic invariant and L*
Abstract: The relation between radiation belt electrons and solar wind/magnetospheric processes is of particular interest due to both scientific and practical needs. Though many studies have focused on this topic, electron data from Van Allen Probes with wide L shell coverage and fine energy resolution, for the first time, enabled this statistical study on the relation between radiation belt electrons and solar wind parameters/geomagnetic indices as a function of first adiabatic invariant μ and L*. Good correlations between electron phase space density (PSD) and solar wind speed, southward IMF Bz, SYM-H, and AL indices are found over wide μ and L* ranges, with higher correlation coefficients and shorter time lags for low-μ electrons than high-μ electrons; the anticorrelation between electron PSD. . .
Date: 01/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023658 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA023658
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Authors: Sarris Theodore E., Li Xinlin, Temerin Michael, Zhao Hong, Califf Sam, et al.
Title: On the Relationship Between Electron Flux Oscillations and ULF Wave-Driven Radial Transport
Abstract: The objective of this study is to investigate the relationship between the levels of electron flux oscillations and radial diffusion for different Phase Space Density (PSD) gradients, through observation and particle tracing simulations under the effect of model Ultra Low Frequency (ULF) fluctuations. This investigation aims to demonstrate that electron flux oscillation is associated with and could be used as an indicator of ongoing radial diffusion. To this direction, flux oscillations are observed through the Van Allen Probes’ MagEIS energetic particle detector; subsequently, flux oscillations are produced in a particle tracing model that simulates radial diffusion by using model magnetic and electric field fluctuations that are approximating measured magnetic and electric field fluctu. . .
Date: 06/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023741 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA023741/full
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Authors: Yue Chao, Jun Chae‐Woo, Bortnik Jacob, An Xin, Ma Qianli, et al.
Title: The Relationship Between EMIC Wave Properties and Proton Distributions Based on Van Allen Probes Observations
Abstract: Plasma kinetic theory predicts that sufficiently anisotropic proton distribution will excite electromagnetic ion cyclotron (EMIC) waves, which in turn relax the proton distribution to a marginally stable state creating an upper bound on the relaxed proton anisotropy. Here, using EMIC wave observations and coincident plasma measurements made by Van Allen Probes in the inner magnetosphere, we show that the proton distributions are well constrained by this instability to a marginally stable state. Near the threshold, the probability of EMIC wave occurrence is highest, having left‐handed polarization and observed near the magnetic equator with relatively small wave normal angles, indicating that these waves are locally generated. In addition, EMIC waves are distributed in two magnetic local . . .
Date: 04/2019 Publisher: Geophysical Research Letters DOI: 10.1029/2019GL082633 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019GL082633
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Authors: Yue Chao, An Xin, Bortnik Jacob, Ma Qianli, Li Wen, et al.
Title: The relationship between the macroscopic state of electrons and the properties of chorus waves observed by the Van Allen Probes
Abstract: Plasma kinetic theory predicts that a sufficiently anisotropic electron distribution will excite whistler mode waves, which in turn relax the electron distribution in such a way as to create an upper bound on the relaxed electron anisotropy. Here using whistler mode chorus wave and plasma measurements by Van Allen Probes, we confirm that the electron distributions are well constrained by this instability to a marginally stable state in the whistler mode chorus waves generation region. Lower band chorus waves are organized by the electron β∥e into two distinct groups: (i) relatively large-amplitude, quasi-parallel waves with inline image and (ii) relatively small-amplitude, oblique waves with inline image. The upper band chorus waves also have enhanced amplitudes close to the instabili. . .
Date: 08/2016 Publisher: Geophysical Research Letters Pages: 7804 - 7812 DOI: 10.1002/2016GL070084 Available at: http://doi.wiley.com/10.1002/2016GL070084
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Authors: Goldstein J, Baker D N, Blake J B, De Pascuale S., Funsten H O, et al.
Title: The relationship between the plasmapause and outer belt electrons
Abstract: We quantify the spatial relationship between the plasmapause and outer belt electrons for a 5 day period, 15–20 January 2013, by comparing locations of relativistic electron flux peaks to the plasmapause. A peak-finding algorithm is applied to 1.8–7.7 MeV relativistic electron flux data. A plasmapause gradient finder is applied to wave-derived electron number densities >10 cm−3. We identify two outer belts. Outer belt 1 is a stable zone of >3 MeV electrons located 1–2 RE inside the plasmapause. Outer belt 2 is a dynamic zone of <3 MeV electrons within 0.5 RE of the moving plasmapause. Electron fluxes earthward of each belt's peak are anticorrelated with cold plasma density. Belt 1 decayed on hiss timescales prior to a disturbance on 17 January and suffered only a modest dropout, pe. . .
Date: 08/2016 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023046 Available at: http://doi.wiley.com/10.1002/2016JA023046
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Authors: Horne R B
Title: Relativistic electron acceleration and precipitation during resonant interactions with whistler-mode chorus
Abstract: 1] Resonant interactions with whistler-mode chorus waves provide an important process for electron loss and acceleration during storm times. We demonstrate that wave propagation significantly affects the electron scattering rates. We show that stormtime chorus waves outside the plasmapause can scatter equatorial electrons ≤60 keV into the loss cone and accelerate trapped electrons up to ∼ MeV energies at large pitch-angles. Using ray tracing to map the waves to higher latitudes, we show that the decrease in the ratio between the electron plasma and gyro frequencies, along with the normalized chorus frequency bandwidth, enable much higher energy electrons ∼1 MeV to be scattered into the loss cone. We suggest that off equatorial pitch-angle scattering by chorus waves is responsible for. . .
Date: 05/2003 Publisher: Geophysical Research Letters DOI: 10.1029/2003GL016973 Available at: http://onlinelibrary.wiley.com/doi/10.1029/2003GL016973/full
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Authors: Hao Y. X., Zong Q.-G., Zhou X.-Z., Rankin R, Chen X. R., et al.
Title: Relativistic electron dynamics produced by azimuthally localized poloidal mode ULF waves: Boomerang-shaped pitch angle evolutions
Abstract: We present an analysis of “boomerang-shaped” pitch angle evolutions of outer radiation belt relativistic electrons observed by the Van Allen Probes after the passage of an interplanetary shock on June 7th, 2014. The flux at different pitch angles is modulated by Pc5 waves, with equatorially mirroring electrons reaching the satellite first. For 90∘ pitch angle electrons, the phase change of the flux modulations across energy exceeds 180∘, and increasingly tilts with time. Using estimates of the arrival time of particles of different pitch angles at the spacecraft location, a scenario is investigated in which shock-induced ULF waves interact with electrons through the drift resonance mechanism in a localized region westward of the spacecraft. Numerical calculations on particle energy. . .
Date: 07/2017 Publisher: Geophysical Research Letters DOI: 10.1002/2017GL074006 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017GL074006/full
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Authors: Matsui H., Torbert R B, Spence H E, Argall M. R., Alm L., et al.
Title: Relativistic electron increase during chorus wave activities on the 6-8 March 2016 geomagnetic storm
Abstract: There was a geomagnetic storm on 6–8 March 2016, in which Van Allen Probes A and B separated by ∼2.5 h measured increase of relativistic electrons with energies ∼ several hundred keV to 1 MeV. Simultaneously, chorus waves were measured by both Van Allen Probes and Magnetospheric Multiscale (MMS) mission. Some of the chorus elements were rising-tones, possibly due to nonlinear effects. These measurements are compared with a nonlinear theory of chorus waves incorporating the inhomogeneity ratio and the field equation. From this theory, a chorus wave profile in time and one-dimensional space is simulated. Test particle calculations are then performed in order to examine the energization rate of electrons. Some electrons are accelerated, although more electrons are decelerated. The measu. . .
Date: 10/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024540 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA024540/full
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Authors: Kurita Satoshi, Miyoshi Yoshizumi, Blake Bernard, Reeves Geoffery D., and Kletzing Craig A.
Title: Relativistic electron microbursts and variations in trapped MeV electron fluxes during the 8-9 October 2012 storm: SAMPEX and Van Allen Probes observations
Abstract: It has been suggested that whistler mode chorus is responsible for both acceleration of MeV electrons and relativistic electron microbursts through resonant wave-particle interactions. Relativistic electron microbursts have been considered as an important loss mechanism of radiation belt electrons. Here we report on the observations of relativistic electron microbursts and flux variations of trapped MeV electrons during the 8–9 October 2012 storm, using the SAMPEX and Van Allen Probes satellites. Observations by the satellites show that relativistic electron microbursts correlate well with the rapid enhancement of trapped MeV electron fluxes by chorus wave-particle interactions, indicating that acceleration by chorus is much more efficient than losses by microbursts during the storm. It . . .
Date: 02/2016 Publisher: Geophysical Research Letters Pages: n/a - n/a DOI: 10.1002/2016GL068260 Available at: http://doi.wiley.com/10.1002/2016GL068260http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2F2016GL068260
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Authors: Summers D.
Title: Relativistic electron pitch-angle scattering by electromagnetic ion cyclotron waves during geomagnetic storms
Abstract: [1] During magnetic storms, relativistic electrons execute nearly circular orbits about the Earth and traverse a spatially confined zone within the duskside plasmapause where electromagnetic ion cyclotron (EMIC) waves are preferentially excited. We examine the mechanism of electron pitch-angle diffusion by gyroresonant interaction with EMIC waves as a cause of relativistic electron precipitation loss from the outer radiation belt. Detailed calculations are carried out of electron cyclotron resonant pitch-angle diffusion coefficients Dαα for EMIC waves in a multi-ion (H+, He+, O+) plasma. A simple functional form for Dαα is used, based on quasi-linear theory that is valid for parallel-propagating, small-amplitude electromagnetic waves of general spectral density. For typical observed EM. . .
Date: 04/2003 Publisher: Journal of Geophysical Research DOI: 10.1029/2002JA009489 Available at: http://onlinelibrary.wiley.com/doi/10.1029/2002JA009489/full
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Authors: Jordanova V K, Albert J, and Miyoshi Y
Title: Relativistic electron precipitation by EMIC waves from self-consistent global simulations
Abstract: [1] We study the effect of electromagnetic ion cyclotron (EMIC) wave scattering on radiation belt electrons during the large geomagnetic storm of 21 October 2001 with minimum Dst = −187 nT. We use our global physics-based model, which solves the kinetic equation for relativistic electrons and H+, O+, and He+ ions as a function of radial distance in the equatorial plane, magnetic local time, energy, and pitch angle. The model includes time-dependent convective transport and radial diffusion and all major loss processes and is coupled with a dynamic plasmasphere model. We calculate the excitation of EMIC waves self-consistently with the evolving plasma populations. Particle interactions with these waves are evaluated according to quasi-linear theory, using diffusion coefficients for a mult. . .
Date: 03/2008 Publisher: Journal of Geophysical Research DOI: 10.1029/2008JA013239 Available at: http://onlinelibrary.wiley.com/doi/10.1029/2008JA013239/abstract
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Authors: Khazanov G., Sibeck D., Tel'nikhin A., and Kronberg T.
Title: Relativistic electron precipitation events driven by electromagnetic ion-cyclotron waves
Abstract: We adopt a canonical approach to describe the stochastic motion of relativistic belt electrons and their scattering into the loss cone by nonlinear EMIC waves. The estimated rate of scattering is sufficient to account for the rate and intensity of bursty electron precipitation. This interaction is shown to result in particle scattering into the loss cone, forming ∼10 s microbursts of precipitating electrons. These dynamics can account for the statistical correlations between processes of energization, pitch angle scattering, and relativistic electron precipitation events, that are manifested on large temporal scales of the order of the diffusion time ∼tens of minutes.
Date: 08/2014 Publisher: Physics of Plasmas Pages: 082901 DOI: 10.1063/1.4892185 Available at: http://scitation.aip.org/content/aip/journal/pop/21/8/10.1063/1.4892185
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Authors: Kurita Satoshi, Kadokura Akira, Miyoshi Yoshizumi, Morioka Akira, Sato Yuka, et al.
Title: Relativistic electron precipitations in association with diffuse aurora: Conjugate observation of SAMPEX and the all sky TV camera at Syowa Station
Abstract: It has been believed that whistler mode waves can cause relativistic electron precipitations. It has been also pointed out that pitch angle scattering of ~keV electrons by whistler mode waves results in diffuse auroras. Thus, it is natural to expect relativistic electron precipitations associated with diffuse auroras. Based on a conjugate observation between the SAMPEX spacecraft and the all-sky TV camera at Syowa Station, we report, for the first time, a case in which relativistic electron precipitations are associated with diffuse aurora. The SAMPEX observation shows that the precipitations of >1 MeV electrons are well accompanied with those of >150 and >400 keV electrons. This indicates that electrons in the energy range from several keV to >1 MeV precipitate into the atmosphere s. . .
Date: 06/2015 Publisher: Geophysical Research Letters DOI: 10.1002/2015GL064564 Available at: http://doi.wiley.com/10.1002/2015GL064564
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Authors: Kanekal S G, Baker D N, Henderson M G, Li W, Fennell J. F., et al.
Title: Relativistic electron response to the combined magnetospheric impact of a coronal mass ejection overlapping with a high-speed stream: Van Allen Probes observations
Abstract: During early November 2013, the magnetosphere experienced concurrent driving by a coronal mass ejection (CME) during an ongoing high-speed stream (HSS) event. The relativistic electron response to these two kinds of drivers, i.e., HSS and CME, is typically different, with the former often leading to a slower buildup of electrons at larger radial distances, while the latter energizing electrons rapidly with flux enhancements occurring closer to the Earth.We present a detailed analysis of the relativistic electron response including radial profiles of phase space density as observed by both MagEIS and REPT instruments on the Van Allen Probes mission. Data from the MagEIS instrument establishes the behavior of lower energy (<1MeV) electrons which span both intermediary and seed populations du. . .
Date: 09/2015 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2015JA021395 Available at: http://doi.wiley.com/10.1002/2015JA021395
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Authors: Artemyev A. V., Mourenas D., Agapitov O. V., and Krasnoselskikh V. V.
Title: Relativistic electron scattering by magnetosonic waves: Effects of discrete wave emission and high wave amplitudes
Abstract: In this paper, we study relativistic electron scattering by fast magnetosonic waves. We compare results of test particle simulations and the quasi-linear theory for different spectra of waves to investigate how a fine structure of the wave emission can influence electron resonant scattering. We show that for a realistically wide distribution of wave normal angles theta (i.e., when the dispersion delta theta >= 0.5 degrees), relativistic electron scattering is similar for a wide wave spectrum and for a spectrum consisting in well-separated ion cyclotron harmonics. Comparisons of test particle simulations with quasi-linear theory show that for delta theta > 0.5 degrees, the quasi-linear approximation describes resonant scattering correctly for a large enough plasma frequency. For a very narr. . .
Date: 06/2015 Publisher: Physics of Plasmas Pages: 062901 DOI: 10.1063/1.4922061 Available at: http://scitation.aip.org/content/aip/journal/pop/22/6/10.1063/1.4922061
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Authors: Baker D N, Kanekal S G, Hoxie V C, Batiste S, Bolton M, et al.
Title: The Relativistic Electron-Proton Telescope (REPT) Instrument on Board the Radiation Belt Storm Probes (RBSP) Spacecraft: Characterization of Earth’s Radiation Belt High-Energy Particle Populations
Abstract: Particle acceleration and loss in the million electron Volt (MeV) energy range (and above) is the least understood aspect of radiation belt science. In order to measure cleanly and separately both the energetic electron and energetic proton components, there is a need for a carefully designed detector system. The Relativistic Electron-Proton Telescope (REPT) on board the Radiation Belt Storm Probe (RBSP) pair of spacecraft consists of a stack of high-performance silicon solid-state detectors in a telescope configuration, a collimation aperture, and a thick case surrounding the detector stack to shield the sensors from penetrating radiation and bremsstrahlung. The instrument points perpendicular to the spin axis of the spacecraft and measures high-energy electrons (up to ∼20 MeV) with exc. . .
Date: 11/2013 Publisher: Space Science Reviews Pages: 337-381 DOI: 10.1007/s11214-012-9950-9 Available at: http://link.springer.com/article/10.1007%2Fs11214-012-9950-9
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Authors: Xiong Ying, Chen Lunjin, Xie Lun, Fu Suiyan, Xia Zhiyang, et al.
Title: Relativistic electron's butterfly pitch angle distribution modulated by localized background magnetic field perturbation driven by hot ring current ions
Abstract: Dayside modulated relativistic electron's butterfly pitch angle distributions (PADs) from ∼200 keV to 2.6 MeV were observed by Van Allen Probe B at L = 5.3 on 15 November 2013. They were associated with localized magnetic dip driven by hot ring current ion (60–100 keV proton and 60–200 keV helium and oxygen) injections. We reproduce the electron's butterfly PADs at satellite's location using test particle simulation. The simulation results illustrate that a negative radial flux gradient contributes primarily to the formation of the modulated electron's butterfly PADs through inward transport due to the inductive electric field, while deceleration due to the inductive electric field and pitch angle change also makes in part contribution. We suggest that localized magnetic field pertur. . .
Date: 05/2017 Publisher: Geophysical Research Letters DOI: 10.1002/2017GL072558 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017GL072558/full
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Authors: Green Janet C, and Kivelson M. G.
Title: Relativistic electrons in the outer radiation belt: Differentiating between acceleration mechanisms
Abstract: Many theoretical models have been developed to explain the rapid acceleration to relativistic energies of electrons that form the Earth's radiation belts. However, after decades of research, none of these models has been unambiguously confirmed by comparison to observations. Proposed models can be separated into two types: internal and external source acceleration mechanisms. Internal source acceleration mechanisms accelerate electrons already present in the inner magnetosphere (L < 6.6), while external source acceleration mechanisms transport and accelerate a source population of electrons from the outer to the inner magnetosphere. In principle, the two types of acceleration mechanisms can be differentiated because they imply that different radial gradients of electron phase space density. . .
Date: 03/2004 Publisher: Journal of Geophysical Research DOI: 10.1029/2003JA010153 Available at: http://onlinelibrary.wiley.com/doi/10.1029/2003JA010153/abstract
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Authors: Mazur J, Friesen L, Lin A, Mabry D, Katz N, et al.
Title: The Relativistic Proton Spectrometer (RPS) for the Radiation Belt Storm Probes Mission
Abstract: The Relativistic Proton Spectrometer (RPS) on the Radiation Belt Storm Probes spacecraft is a particle spectrometer designed to measure the flux, angular distribution, and energy spectrum of protons from ∼60 MeV to ∼2000 MeV. RPS will investigate decades-old questions about the inner Van Allen belt proton environment: a nearby region of space that is relatively unexplored because of the hazards of spacecraft operation there and the difficulties in obtaining accurate proton measurements in an intense penetrating background. RPS is designed to provide the accuracy needed to answer questions about the sources and losses of the inner belt protons and to obtain the measurements required for the next-generation models of trapped protons in the magnetosphere. In addition to detailed informati. . .
Date: 11/2013 Publisher: Space Science Reviews Pages: 221-261 DOI: 10.1007/s11214-012-9926-9 Available at: http://link.springer.com/article/10.1007%2Fs11214-012-9926-9
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Authors: Summers D., Thorne Richard M, and Xiao Fuliang
Title: Relativistic theory of wave-particle resonant diffusion with application to electron acceleration in the magnetosphere
Abstract: Resonant diffusion curves for electron cyclotron resonance with field-aligned electromagnetic R mode and L mode electromagnetic ion cyclotron (EMIC) waves are constructed using a fully relativistic treatment. Analytical solutions are derived for the case of a single-ion plasma, and a numerical scheme is developed for the more realistic case of a multi-ion plasma. Diffusion curves are presented, for plasma parameters representative of the Earth's magnetosphere at locations both inside and outside the plasmapause. The results obtained indicate minimal electron energy change along the diffusion curves for resonant interaction with L mode waves. Intense storm time EMIC waves are therefore ineffective for electron stochastic acceleration, although these waves could induce rapid pitch angle scat. . .
Date: 09/1998 Publisher: Journal of Geophysical Research Pages: 20487 - 20500 DOI: 10.1029/98JA01740 Available at: http://onlinelibrary.wiley.com/doi/10.1029/98JA01740/abstract
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Authors: Johnston Wm. Robert, O'Brien Paul, Ginet Gregory P., and the AE9/AP9/SPM team
Title: Release of AE9/AP9/SPM Radiation Belt and Space Plasma Model Version 1.20.002
Abstract: N/A
Date: 05/2015 Publisher: Space Weather DOI: 10.1002/2015SW001212 Available at: http://doi.wiley.com/10.1002/2015SW001212
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Authors: Chen Yue, Friedel Reiner H W, Henderson Michael G., Claudepierre Seth G., Morley Steven K., et al.
Title: REPAD: An empirical model of pitch angle distributions for energetic electrons in the Earth's outer radiation belt
Abstract: We have recently conducted a statistical survey on pitch angle distributions of energetic electrons trapped in the Earth's outer radiation belt, and a new empirical model was developed based upon survey results. This model—relativistic electron pitch angle distribution (REPAD)—aims to present statistical pictures of electron equatorial pitch angle distributions, instead of the absolute flux levels, as a function of energy, L shell, magnetic local time, and magnetic activity. To quantify and facilitate this statistical survey, we use Legendre polynomials to fit long-term in situ directional fluxes observed near the magnetic equator from three missions: CRRES, Polar, and LANL-97A. As the first of this kind of model, REPAD covers the whole outer belt region, providing not only the mean an. . .
Date: 03/2014 Publisher: Journal of Geophysical Research: Space Physics Pages: 1693 - 1708 DOI: 10.1002/jgra.v119.310.1002/2013JA019431 Available at: http://doi.wiley.com/10.1002/jgra.v119.3http://doi.wiley.com/10.1002/2013JA019431
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Authors: Chen Y., Friedel R. H. W., Henderson M. G., Claudepierre S. G., Morley S., et al.
Title: REPAD: An Empirical Model of Pitch-angle Distributions for Energetic Electrons in the Earth’s Outer Radiation Belt
Abstract: We have recently conducted a statistical survey on pitch angle distributions of energetic electrons trapped in the Earth's outer radiation belt, and a new empirical model was developed based upon survey results. This model—relativistic electron pitch angle distribution (REPAD)—aims to present statistical pictures of electron equatorial pitch angle distributions, instead of the absolute flux levels, as a function of energy, L shell, magnetic local time, and magnetic activity. To quantify and facilitate this statistical survey, we use Legendre polynomials to fit long-term in situ directional fluxes observed near the magnetic equator from three missions: CRRES, Polar, and LANL-97A. As the first of this kind of model, REPAD covers the whole outer belt region, providing not only the mean an. . .
Date: 03/2014 Publisher: Journal of Geophysical Research Pages: 1693-1708 DOI: 10.1002/2013JA019431 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2013JA019431/full
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Authors: Mozer F S, Hull A., Lejosne S., and Vasko I. Y.
Title: Reply to Comment by Nishimura Et Al.
Abstract: Nishimura et al. (2010, https://doi.org/10.1126/science.1193186, 2011, https://doi.org/10.1029/2011JA016876, 2013, https://doi.org/10.1029/2012JA018242, and in their comment, hereafter called N18) have suggested that chorus waves interact with equatorial electrons to produce pulsating auroras. We agree that chorus can scatter electrons >10 keV, as do Time Domain Structures (TDSs). Lower‐energy electrons occurring in pulsating auroras cannot be produced by chorus, but such electrons are scattered and accelerated by TDS. TDSs often occur with chorus and have power in their spectra at chorus frequencies. Thus, the absence of power at low frequencies is not evidence that TDSs are absent, as an example shows. Through examination of equatorial electric field waveforms and electron pitch angle . . .
Date: 03/2018 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2018JA025218 Available at: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2018JA025218
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Authors: Mann I. R., Ozeke L. G., Morley S. K., Murphy K. R., Claudepierre S G, et al.
Title: Reply to 'The dynamics of Van Allen belts revisited'
Abstract: N/A
Date: 02/2019 Publisher: Nature Physics Pages: 103 - 104 DOI: 10.1038/nphys4351 Available at: http://www.nature.com/doifinder/10.1038/nphys4351
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Authors: Ripoll J. F., Reeves G., Cunningham G., Loridan V., Denton M., et al.
Title: Reproducing the observed energy-dependent structure of Earth's electron radiation belts during storm recovery with an event-specific diffusion model
Abstract: We present dynamic simulations of energy-dependent losses in the radiation belt " slot region" and the formation of the two-belt structure for the quiet days after the March 1st storm. The simulations combine radial diffusion with a realistic scattering model, based data-driven spatially and temporally-resolved whistler mode hiss wave observations from the Van Allen Probes satellites. The simulations reproduce Van Allen Probes observations for all energies and L-shells (2 to 6) including (a) the strong energy-dependence to the radiation belt dynamics (b) an energy-dependent outer boundary to the inner zone that extends to higher L-shells at lower energies and (c) an " S-shaped" energy-dependent inner boundary to the outer zone that results from the competition between diffusive radial tran. . .
Date: 05/2016 Publisher: Geophysical Research Letters DOI: 10.1002/2016GL068869 Available at: http://doi.wiley.com/10.1002/2016GL068869
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Authors: Elkington Scot R
Title: Resonant acceleration and diffusion of outer zone electrons in an asymmetric geomagnetic field
Abstract: [1] The outer zone radiation belt consists of energetic electrons drifting in closed orbits encircling the Earth between ∼3 and 7 RE. Electron fluxes in the outer belt show a strong correlation with solar and magnetospheric activity, generally increasing during geomagnetic storms with associated high solar wind speeds, and increasing in the presence of magnetospheric ULF waves in the Pc-5 frequency range. In this paper, we examine the influence of Pc-5 ULF waves on energetic electrons drifting in an asymmetric, compressed dipole and find that such particles may be efficiently accelerated through a drift-resonant interaction with the waves. We find that the efficiency of this acceleration increases with increasing magnetospheric distortion (such as may be attributed to increased solar win. . .
Date: 03/2003 Publisher: Journal of Geophysical Research DOI: 10.1029/2001JA009202 Available at: http://onlinelibrary.wiley.com/doi/10.1029/2001JA009202/full
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Authors: Degeling A W, and Rankin R
Title: Resonant drift echoes in electron phase space density produced by dayside Pc5 waves following a geomagnetic storm
Abstract: [1] The interaction between relativistic, equatorially mirroring electrons and Pc5 Ultra Low Frequency (ULF) waves in the magnetosphere is investigated using a numerical MagnetoHydroDynamic (MHD) model for waves and a test-kinetic model for electron phase space density (PSD). The temporal and spatial characteristics of a ULF wave packet are constrained using ground-based observations of narrowband ULF activity following a geomagnetic storm on 24 March 1991, which occurred from 1200 to 1340 Universal Time (UT). A salient feature of the ULF waves during this interval was the apparent localization of the ULF wave power to the dayside of the magnetosphere and the antisunward propagation of ULF wave phase in the morning and afternoon sectors. This is interpreted to imply a localized source of U. . .
Date: 10/2008 Publisher: Journal of Geophysical Research DOI: 10.1029/2008JA013254 Available at: http://onlinelibrary.wiley.com/doi/10.1029/2008JA013254/abstract
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Authors: Ni Binbin, Bortnik Jacob, Thorne Richard M, Ma Qianli, and Chen Lunjin
Title: Resonant scattering and resultant pitch angle evolution of relativistic electrons by plasmaspheric hiss
Abstract: We perform a comprehensive analysis to evaluate hiss-induced scattering effect on the pitch angle evolution and associated decay processes of relativistic electrons. The results show that scattering by the equatorial, highly oblique hiss component is negligible. Quasi-parallel approximation is good for evaluation of hiss-driven electron scattering rates ≤ 2 MeV. However, realistic wave propagation angles as a function of latitude must be considered to accurately quantify hiss scattering rates above 2 MeV, and ambient plasma density is also a critical parameter. While the first-order cyclotron and the Landau resonances are dominant for hiss scattering < 2 MeV electrons, higher-order resonances become important and even dominant at intermediate pitch angles for ultrarelativistic (≥. . .
Date: 12/2013 Publisher: Journal of Geophysical Research: Space Physics Pages: 7740 - 7751 DOI: 10.1002/2013JA019260 Available at: http://doi.wiley.com/10.1002/2013JA019260
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Authors: Ni Binbin, Li Wen, Thorne Richard M, Bortnik Jacob, Ma Qianli, et al.
Title: Resonant scattering of energetic electrons by unusual low-frequency hiss
Abstract: We quantify the resonant scattering effects of the unusual low-frequency dawnside plasmaspheric hiss observed on 30 September 2012 by the Van Allen Probes. In contrast to normal (~100–2000 Hz) hiss emissions, this unusual hiss event contained most of its wave power at ~20–200 Hz. Compared to the scattering by normal hiss, the unusual hiss scattering speeds up the loss of ~50–200 keV electrons and produces more pronounced pancake distributions of ~50–100 keV electrons. It is demonstrated that such unusual low-frequency hiss, even with a duration of a couple of hours, plays a particularly important role in the decay and loss process of energetic electrons, resulting in shorter electron lifetimes for ~50–400 keV electrons than normal hiss, and should be carefully incorpora. . .
Date: 03/2014 Publisher: Geophysical Research Letters Pages: 1854 - 1861 DOI: 10.1002/2014GL059389 Available at: http://doi.wiley.com/10.1002/2014GL059389
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Authors: Ni Binbin, Cao Xing, Zou Zhengyang, Zhou Chen, Gu Xudong, et al.
Title: Resonant scattering of outer zone relativistic electrons by multiband EMIC waves and resultant electron loss time scales
Abstract: To improve our understanding of the role of electromagnetic ion cyclotron (EMIC) waves in radiation belt electron dynamics, we perform a comprehensive analysis of EMIC wave-induced resonant scattering of outer zone relativistic (>0.5 MeV) electrons and resultant electron loss time scales with respect to EMIC wave band, L shell, and wave normal angle model. The results demonstrate that while H+-band EMIC waves dominate the scattering losses of ~1–4 MeV outer zone relativistic electrons, it is He+-band and O+-band waves that prevail over the pitch angle diffusion of ultrarelativistic electrons at higher energies. Given the wave amplitude, EMIC waves at higher L shells tend to resonantly interact with a larger population of outer zone relativistic electrons and drive their pitch angle s. . .
Date: 09/2015 Publisher: Journal of Geophysical Research: Space Physics Pages: 7357 - 7373 DOI: 10.1002/2015JA021466 Available at: http://doi.wiley.com/10.1002/2015JA021466http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2F2015JA021466
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Authors: Ni Binbin, Zou Zhengyang, Fu Song, Cao Xing, Gu Xudong, et al.
Title: Resonant Scattering of Radiation Belt Electrons by Off-Equatorial Magnetosonic Waves
Abstract: Fast magnetosonic (MS) waves are commonly regarded as electromagnetic waves that are characteristically confined within ±3° of the geomagnetic equator. We report two typical off-equatorial MS events observed by Van Allen Probes, that is, the 8 May 2014 event that occurred at the geomagnetic latitudes of 7.5°–9.2° both inside and outside the plasmasphere with the wave amplitude up to 590 pT and the 9 January 2014 event that occurred at the latitudes of—(15.7°–17.5°) outside the plasmasphere with a smaller amplitude about 81 pT. Detailed test particle simulations quantify the electron resonant scattering rates by the off-equatorial MS waves to find that they can cause the pitch angle scattering and momentum diffusion of radiation belt electrons with equatorial pitch angles < ~75. . .
Date: 02/2018 Publisher: Geophysical Research Letters Pages: 1228 - 1236 DOI: 10.1002/grl.v45.310.1002/2017GL075788 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017GL075788/full
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Authors: Yu Xiongdong, Yuan Zhigang, Li Haimeng, Huang Shiyong, Wang Dedong, et al.
Title: Response of banded whistler-mode waves to the enhancement of solar wind dynamic pressure in the inner Earth's magnetosphere
Abstract: With observations of Van Allen Probe A, in this letter we display a typical event where banded whistler waves shifted up their frequencies with frequency bands broadening as a response to the enhancement of solar wind dynamic pressure. Meanwhile, the anisotropy of electrons with energies about several tens of keV was observed to increase. Through the comparison of the calculated wave growth rates and observed wave spectral intensity, we suggest that those banded whistler waves observed with frequencies shifted up and frequency bands broadening could be locally excited by these hot electrons with increased anisotropy. The current study provides a great in situ evidence for the influence on frequencies of banded whistler waves by the enhancement of solar wind dynamic pressures, which reveals. . .
Date: Mar-08-2020 Publisher: Geophysical Research Letters DOI: 10.1029/2018GL078849 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL078849
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Authors: Motoba T., Ohtani S, Gkioulidou M., Ukhorskiy A., Mitchell D G, et al.
Title: Response of Different Ion Species to Local Magnetic Dipolarization Inside Geosynchronous Orbit
Abstract: This paper examines how hydrogen, helium and oxygen (H, He and O) ion fluxes at 1–1000 keV typically respond to local magnetic dipolarization inside geosynchronous orbit (GEO). We extracted 144 dipolarizations which occurred at magnetic inclination > 30° from the 2012–2016 tail seasons' observations of the Van Allen Probes spacecraft and then defined typical flux changes of these ion species by performing a superposed epoch analysis. On average, the dipolarization inside GEO is accompanied by a precursory transient decrease in the northward magnetic field component, transient impulsive enhancement in the westward electric field component, and decrease (increase) in the proton density (temperature). The coincident ion species experience an energy‐dependent flux change, consisting of . . .
Date: 06/2018 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2018JA025557 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JA025557
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