Biblio

Found 879 results
2017
Authors: Blum L. W., Bonnell J. W., Agapitov O., Paulson K., and Kletzing C.
Title: EMIC wave scale size in the inner magnetosphere: Observations from the dual Van Allen Probes
Abstract: Estimating the spatial scales of electromagnetic ion cyclotron (EMIC) waves is critical for quantifying their overall scattering efficiency and effects on thermal plasma, ring current, and radiation belt particles. Using measurements from the dual Van Allen Probes in 2013–2014, we characterize the spatial and temporal extents of regions of EMIC wave activity and how these depend on local time and radial distance within the inner magnetosphere. Observations are categorized into three types—waves observed by only one spacecraft, waves measured by both spacecraft simultaneously, and waves observed by both spacecraft with some time lag. Analysis reveals that dayside (and H+ band) EMIC waves more frequently span larger spatial areas, while nightside (and He+ band) waves are more often loc. . .
Date: 02/2017 Publisher: Geophysical Research Letters Pages: 1227 - 1233 DOI: 10.1002/2016GL072316 Available at: http://doi.wiley.com/10.1002/2016GL072316
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Title: EMIC wave scale size in the inner magnetosphere: Observations from the dual Van Allen Probes
Abstract: Estimating the spatial scales of electromagnetic ion cyclotron (EMIC) waves is critical for quantifying their overall scattering efficiency and effects on thermal plasma, ring current, and radiation belt particles. Using measurements from the dual Van Allen Probes in 2013–2014, we characterize the spatial and temporal extents of regions of EMIC wave activity and how these depend on local time and radial distance within the inner magnetosphere. Observations are categorized into three types—waves observed by only one spacecraft, waves measured by both spacecraft simultaneously, and waves observed by both spacecraft with some time lag. Analysis reveals that dayside (and H+ band) EMIC waves more frequently span larger spatial areas, while nightside (and He+ band) waves are more often loc. . .
Date: 01/2017 Publisher: Geophysical Research Letters DOI: 10.1002/2016GL072316 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016GL072316
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Authors: Yu Xiongdong, Yuan Zhigang, Huang Shiyong, Wang Dedong, Li Haimeng, et al.
Title: EMIC waves covering wide L shells: MMS and Van Allen Probes observations
Abstract: During 04:45:00–08:15:00 UT on 13 September in 2015, a case of Electromagnetic ion cyclotron (EMIC) waves covering wide L shells (L = 3.6–9.4), observed by the Magnotospheric Multiscale 1 (MMS1) are reported. During the same time interval, EMIC waves observed by Van Allen Probes A (VAP-A) only occurred just outside the plasmapause. As the Van Allen Probes moved outside into a more tenuous plasma region, no intense waves were observed. Combined observations of MMS1 and VAP-A suggest that in the terrestrial magnetosphere, an appropriately dense background plasma would make contributions to the growth of EMIC waves in lower L shells, while the ion anisotropy, driven by magnetospheric compression, might play an important role in the excitation of EMIC waves in higher L shells. These EMIC w. . .
Date: 07/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA023982 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA023982/full
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Authors: Zhelavskaya Irina S., Shprits Yuri Y, and ć Maria
Title: Empirical modeling of the plasmasphere dynamics using neural networks
Abstract: We propose a new empirical model for reconstructing the global dynamics of the cold plasma density distribution based only on solar wind data and geomagnetic indices. Utilizing the density database obtained using the NURD (Neural-network-based Upper hybrid Resonance Determination) algorithm for the period of October 1, 2012 - July 1, 2016, in conjunction with solar wind data and geomagnetic indices, we develop a neural network model that is capable of globally reconstructing the dynamics of the cold plasma density distribution for 2≤L≤6 and all local times. We validate and test the model by measuring its performance on independent datasets withheld from the training set and by comparing the model predicted global evolution with global images of He+ distribution in the Earth's plasmasph. . .
Date: 10/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024406 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA024406/full
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Authors: Andreeva V. A., and Tsyganenko N A
Title: Empirical modeling of the quiet and storm-time geosynchronous magnetic field
Abstract: A dynamical empirical model of the near-geosynchronous magnetic field has been constructed, based on a recently developed RBF approach and a multi-year set of spacecraft data taken by THEMIS, Polar, Cluster, and Van Allen Probes missions including 133 geomagnetic storms in the time interval between 1996 and 2016. The model describes the field as a function of Cartesian solar-magnetic coordinates, dipole tilt angle, solar wind ram pressure, and of a set of dynamic variables representing the response of the magnetosphere to the external driving/loading during the active phase of a space weather event, followed by the internal relaxation/dissipation during the storm recovery. In terms of the disturbance level, the model's validity range extends to intense storms with peak Sym-H values down to. . .
Date: 12/2017 Publisher: Space Weather DOI: 10.1002/2017SW001684 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017SW001684/full
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Authors: Pich Maria de Soria-S, Jun Insoo, and Evans Robin
Title: Empirical radiation belt models: Comparison with in-situ data and implications for environment definition
Abstract: The empirical AP8/AE8 model has been the de-facto Earth's radiation belts engineering reference for decades. The need from the community for a better model incubated the development of AP9/AE9/SPM, which addresses several shortcomings of the old model. We provide additional validation of AP9/AE9 by comparing in-situ electron and proton data from Jason-2, POES, and the Van Allen Probes spacecraft with the 5th, 50th, and 95th percentiles from AE9/AP9 and with the model outputs from AE8/AP8. The relatively short duration of Van Allen Probes and Jason-2 missions means that their measurements are most certainly the result of specific climatological conditions. In LEO, the Jason-2 proton flux is better reproduced by AP8 compared to AP9, while the POES electron data are well enveloped by AE9 5th . . .
Date: 08/2017 Publisher: Space Weather DOI: 10.1002/2017SW001612 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017SW001612/full
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Authors: Oyama S., Kero A., Rodger C. J., Clilverd M A, Miyoshi Y, et al.
Title: Energetic electron precipitation and auroral morphology at the substorm recovery phase
Abstract: It is well known that auroral patterns at the substorm recovery phase are characterized by diffuse or patch structures with intensity pulsation. According to satellite measurements and simulation studies, the precipitating electrons associated with these aurorae can reach or exceed energies of a few hundreds of keV through resonant wave-particle interactions in the magnetosphere. However, because of difficulty of simultaneous measurements, the dependency of energetic electron precipitation (EEP) on auroral morphological changes in the mesoscale has not been investigated to date. In order to study this dependency, we have analyzed data from the European Incoherent Scatter (EISCAT) radar, the Kilpisjärvi Atmospheric Imaging Receiver Array (KAIRA) riometer, collocated cameras, ground-based m. . .
Date: 05/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023484 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA023484/full
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Authors: Summers Danny, Shi Run, Engebretson Mark J, Oksavik Kjellmar, Manweiler Jerry W., et al.
Title: Energetic proton spectra measured by the Van Allen Probes
Abstract: We test the hypothesis that pitch-angle scattering by electromagnetic ion cyclotron (EMIC) waves can limit ring current proton fluxes. For two chosen magnetic storms, during March 17-20, 2013 and March 17-20, 2015, we measure proton energy spectra in the region 3 ≤ L ≤ 6 using the RBSPICE B instrument on the Van Allen Probes. The most intense proton spectra are observed to occur during the recovery periods of the respective storms. Using proton precipitation data from the POES (NOAA and MetOp) spacecraft, we deduce that EMIC wave action was prevalent at the times and L-shell locations of the most intense proton spectra. We calculate limiting ring current proton energy spectra from recently developed theory. Comparisons between the observed proton energy spectra and the theoreti. . .
Date: 09/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024484 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA024484/full
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Authors: Denton M. H., Thomsen M F, Reeves G D, Larsen B A, Henderson M G, et al.
Title: The Evolution of the Plasma Sheet Ion Composition: Storms and Recoveries
Abstract: The ion plasma sheet (~few hundred eV to ~few 10s keV) is usually dominated by H+ ions. Here, changes in ion composition within the plasma sheet are explored both during individual events, and statistically during 54 calm-to-storm events and during 21 active-to-calm events. Ion composition data from the HOPE (Helium, Oxygen, Proton, Electron) instruments onboard Van Allen Probes satellites provide exceptional spatial and temporal resolution of the H+, O+, and He+ ion fluxes in the plasma sheet. H+ shown to be the dominant ion in the plasma sheet in the calm-to-storm transition. However, the energy-flux of each ion changes in a quasi-linear manner during extended calm intervals. Heavy ions (O+ and He+) become increasingly important during such periods as charge-exchange reactions result in . . .
Date: 10/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024475 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA024475/full
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Authors: Turner D. L., Lee J. H., Claudepierre S G, Fennell J. F., Blake J B, et al.
Title: Examining coherency scales, substructure, and propagation of whistler-mode chorus elements with Magnetospheric Multiscale (MMS)
Abstract: Whistler-mode chorus waves are a naturally occurring electromagnetic emission observed in Earth's magnetosphere. Here, for the first time, data from NASA's Magnetospheric Multiscale (MMS) mission were used to analyze chorus waves in detail, including the calculation of chorus wave normal vectors, k. A case study was examined from a period of substorm activity around the time of a conjunction between the MMS constellation and NASA's Van Allen Probes mission on 07 April 2016. Chorus wave activity was simultaneously observed by all six spacecraft over a broad range of L-shells (5.5 < L < 8.5), magnetic local time (06:00 < MLT < 09:00), and magnetic latitude (-32° < MLat < -15°), implying a large chorus active region. Eight chorus elements and their substructure were analyzed in detail with . . .
Date: 10/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024474 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA024474/full
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Authors: Takahashi Kazue, Denton Richard E., Kurth William, Kletzing Craig, Wygant John, et al.
Title: Externally driven plasmaspheric ULF waves observed by the Van Allen Probes
Abstract: We analyze data acquired by the Van Allen Probes on 8 November 2012, during a period of extended low geomagnetic activity, to gain new insight into plasmaspheric ultralow frequency (ULF) waves. The waves exhibited strong spectral power in the 5–40 mHz band and included multiharmonic toroidal waves visible up to the eleventh harmonic, unprecedented in the plasmasphere. During this wave activity, the interplanetary magnetic field cone angle was small, suggesting that the waves were driven by broadband compressional ULF waves originating in the foreshock region. This source mechanism is supported by the tailward propagation of the compressional magnetic field perturbations at a phase velocity of a few hundred kilometers per second that is determined by the cross-phase analysis of data from . . .
Date: 01/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2014JA020373 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2014JA020373
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Authors: Xiao Fuliang, Liu Si, Tao Xin, Su Zhenpeng, Zhou Qinghua, et al.
Title: Generation of extremely low frequency chorus in Van Allen radiation belts
Abstract: Recent studies have shown that chorus can efficiently accelerate the outer radiation belt electrons to relativistic energies. Chorus, previously often observed above 0.1 equatorial electron gyrofrequency fce, was generated by energetic electrons originating from Earth's plasma sheet. Chorus below 0.1 fce has seldom been reported until the recent data from Van Allen Probes, but its origin has not been revealed so far. Because electron resonant energy can approach the relativistic level at extremely low frequency, relativistic effects should be considered in the formula for whistler mode wave growth rate. Here we report high-resolution observations during the 14 October 2014 small storm and firstly demonstrate, using a fully relativistic simulation, that electrons with the high-energy tail p. . .
Date: 03/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023561 Available at: http://doi.wiley.com/10.1002/2016JA023561
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Authors: Fu Xiangrong, Gary Peter, Reeves Geoffrey D, Winske Dan, and Woodroffe Jesse R.
Title: Generation of Highly Oblique Lower-band Chorus via Nonlinear Three-wave Resonance
Abstract: Chorus in the inner magnetosphere has been observed frequently at geomagnetically active times, typically exhibiting a two-band structure with a quasi-parallel lower-band and an upper-band with a broad range of wave normal angles. But recent observations by Van Allen Probes confirm another type of lower-band chorus, which has a large wave normal angle close to the resonance cone angle. It has been proposed that these waves could be generated by a low-energy beam-like electron component or by temperature anisotropy of keV electrons in the presence of a low-energy plateau-like electron component. This paper, however, presents an alternative mechanism for generation of this highly oblique lower-band chorus. Through a nonlinear three-wave resonance, a quasi-parallel lower-band chorus wave can . . .
Date: 09/2017 Publisher: Geophysical Research Letters DOI: 10.1002/2017GL074411 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017GL074411/full
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Authors: Zhou Qinghua, Xiao Fuliang, Yang Chang, Liu Si, He Yihua, et al.
Title: Generation of lower and upper bands of electrostatic electron cyclotron harmonic waves in the Van Allen radiation belts
Abstract: Electrostatic electron cyclotron harmonic (ECH) waves generated by the electron loss cone distribution can produce efficient scattering loss of plasma sheet electrons, which has a significant effect on the dynamics in the outer magnetosphere. Here we report two ECH emission events around the same location L≈ 5.7–5.8, MLT ≈ 12 from Van Allen Probes on 11 February (event A) and 9 January 2014 (event B), respectively. The spectrum of ECH waves was centered at the lower half of the harmonic bands during event A, but the upper half during event B. The observed electron phase space density in both events is fitted by the subtracted bi-Maxwellian distribution, and the fitting functions are used to evaluate the local growth rates of ECH waves based on a linear theory for homogeneous plasmas.. . .
Date: 05/2017 Publisher: Geophysical Research Letters DOI: 10.1002/2017GL073051 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017GL073051/full
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Authors: Reeves G. D., and Daglis I. A.
Title: Geospace Magnetic Storms and the Van Allen Radiation Belts
Abstract: N/A
Date: Publisher: Oxford University Press DOI: N/A
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Authors: Le G., Chi P. J., Strangeway R J, Russell C. T., Slavin J. A., et al.
Title: Global observations of magnetospheric high- m poloidal waves during the 22 June 2015 magnetic storm
Abstract: We report global observations of high-m poloidal waves during the recovery phase of the 22 June 2015 magnetic storm from a constellation of widely spaced satellites of five missions including Magnetospheric Multiscale (MMS), Van Allen Probes, Time History of Events and Macroscale Interactions during Substorm (THEMIS), Cluster, and Geostationary Operational Environmental Satellites (GOES). The combined observations demonstrate the global spatial extent of storm time poloidal waves. MMS observations confirm high azimuthal wave numbers (m ~ 100). Mode identification indicates the waves are associated with the second harmonic of field line resonances. The wave frequencies exhibit a decreasing trend as L increases, distinguishing them from the single-frequency global poloidal modes normally obs. . .
Date: 04/2017 Publisher: Geophysical Research Letters DOI: 10.1002/2017GL073048 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017GL073048/full
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Authors: Claudepierre S G, O'Brien T P, Fennell J. F., Blake J B, Clemmons J. H., et al.
Title: The hidden dynamics of relativistic electrons (0.7-1.5 MeV) in the inner zone and slot region
Abstract: We present measurements of relativistic electrons (0.7–1.5 MeV) in the inner zone and slot region obtained by the Magnetic Electron and Ion Spectrometer (MagEIS) instrument on Van Allen Probes. The data presented are corrected for background contamination, which is primarily due to inner-belt protons in these low-L regions. We find that ∼1 MeV electrons were transported into the inner zone following the two largest geomagnetic storms of the Van Allen Probes era to date, the March and June 2015 events. As ∼1 MeV electrons were not observed in Van Allen Probes data in the inner zone prior to these two events, the injections created a new inner belt that persisted for at least 1.5 years. In contrast, we find that electrons injected into the slot region decay on much faster timescales, a. . .
Date: 03/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023719 Available at: http://doi.wiley.com/10.1002/2016JA023719http://onlinelibrary.wiley.com/wol1/doi/10.1002/2016JA023719
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Authors: Claudepierre S G, O'Brien T P, Fennell J. F., Blake J B, Clemmons J. H., et al.
Title: The hidden dynamics of relativistic electrons (0.7-1.5 MeV) in the inner zone and slot region
Abstract: We present measurements of relativistic electrons (0.7–1.5 MeV) in the inner zone and slot region obtained by the Magnetic Electron and Ion Spectrometer (MagEIS) instrument on Van Allen Probes. The data presented are corrected for background contamination, which is primarily due to inner-belt protons in these low-L regions. We find that ∼1 MeV electrons were transported into the inner zone following the two largest geomagnetic storms of the Van Allen Probes era to date, the March and June 2015 events. As ∼1 MeV electrons were not observed in Van Allen Probes data in the inner zone prior to these two events, the injections created a new inner belt that persisted for at least 1.5 years. In contrast, we find that electrons injected into the slot region decay on much faster timescales, a. . .
Date: 03/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023719 Available at: http://doi.wiley.com/10.1002/2016JA023719
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Authors: Yuan Zhigang, Yu Xiongdong, Huang Shiyong, Wang Dedong, and Funsten Herbert O.
Title: In situ observations of magnetosonic waves modulated by background plasma density
Abstract: We report in situ observations by the Van Allen Probe mission that magnetosonic (MS) waves are clearly relevant to appear relevant to the background plasma number density. As the satellite moved across dense and tenuous plasma alternatively, MS waves occurred only in lower density region. As the observed protons with ‘ring’ distributions provide free energy, local linear growth rates are calculated and show that magnetosonic waves can be locally excited in tenuous plasma. With variations of the background plasma density, the temporal variations of local wave growth rates calculated with the observed proton ring distributions, show a remarkable agreement with those of the observed wave amplitude. Therefore, the paper provides a direct proof that background plasma densities can modulate . . .
Date: 07/2017 Publisher: Geophysical Research Letters DOI: 10.1002/2017GL074681 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017GL074681/full
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Authors: Hartley D. P., Kletzing C A, Kurth W S, Hospodarsky G B, Bounds S R, et al.
Title: An improved sheath impedance model for the Van Allen probes EFW instrument: Effects of the spin axis antenna
Abstract: A technique to quantitatively determine the sheath impedance of the Van Allen Probes Electric Field and Waves (EFW) instrument is presented. This is achieved, for whistler mode waves, through a comparison between the total electric field wave power spectra calculated from magnetic field observations and cold plasma theory, and the total electric field wave power measured by the EFW spherical double probes instrument. In a previous study, a simple density-dependent sheath impedance model was developed in order to account for the differences between the observed and calculated wave electric field. The current study builds on this previous work by investigating the remaining discrepancies, identifying their cause, and developing an improved sheath impedance correction. Analysis reveals that a. . .
Date: 03/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023597 Available at: http://doi.wiley.com/10.1002/2016JA023597
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Authors: Brito Thiago V., and Morley Steven K.
Title: Improving empirical magnetic field models by fitting to in situ data using an optimized parameter approach
Abstract: A method for comparing and optimizing the accuracy of empirical magnetic field models using in situ magnetic field measurements is presented. The optimization method minimizes a cost function - τ - that explicitly includes both a magnitude and an angular term. A time span of 21 days, including periods of mild and intense geomagnetic activity, was used for this analysis. A comparison between five magnetic field models (T96, T01S, T02, TS04, TS07) widely used by the community demonstrated that the T02 model was, on average, the most accurate when driven by the standard model input parameters. The optimization procedure, performed in all models except TS07, generally improved the results when compared to unoptimized versions of the models. Additionally, using more satellites in the optimizat. . .
Date: 10/2017 Publisher: Space Weather DOI: 10.1002/2017SW001702 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017SW001702/full
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Authors: Zhang Yang, Shi Run, Ni Binbin, Gu Xudong, Zhang Xianguo, et al.
Title: Inferring electromagnetic ion cyclotron wave intensity from low altitude POES proton flux measurements: A detailed case study with conjugate Van Allen Probes observations
Abstract: N/A
Date: 03/2017 Publisher: Advances in Space Research Pages: 1568 - 1576 DOI: 10.1016/j.asr.2016.12.035 Available at: http://www.sciencedirect.com/science/article/pii/S0273117716307578
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Authors: McCollough J. P., Quinn J. M., Starks M. J., and Johnston W R
Title: Intelligent Sampling of Hazardous Particle Populations in Resource-Constrained Environments
Abstract: Sampling of anomaly-causing space environment drivers is necessary for both real-time operations and satellite design efforts, and optimizing measurement sampling helps minimize resource demands. Relating these measurements to spacecraft anomalies requires the ability to resolve spatial and temporal variability in the energetic charged particle hazard of interest. Here we describe a method for sampling particle fluxes informed by magnetospheric phenomenology so that, along a given trajectory, the variations from both temporal dynamics and spatial structure are adequately captured while minimizing oversampling. We describe the coordinates, sampling method, and specific regions and parameters employed. We compare resulting sampling cadences with data from spacecraft spanning the regions of i. . .
Date: 10/2017 Publisher: Space Weather DOI: 10.1002/2017SW001629 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017SW001629/full
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Authors: Turner D L, O'Brien T. P., Fennell J F, Claudepierre S. G., Blake J. B., et al.
Title: Investigating the source of near-relativistic and relativistic electrons in Earth's inner radiation belt
Abstract: Using observations from NASA's Van Allen Probes, we study the role of sudden particle enhancements at low L shells (SPELLS) as a source of inner radiation belt electrons. SPELLS events are characterized by electron intensity enhancements of approximately an order of magnitude or more in less than 1 day at L < 3. During quiet and average geomagnetic conditions, the phase space density radial distributions for fixed first and second adiabatic invariants are peaked at 2 < L < 3 for electrons ranging in energy from ~50 keV to ~1 MeV, indicating that slow inward radial diffusion is not the dominant source of inner belt electrons under quiet/average conditions. During SPELLS events, the evolution of electron distributions reveals an enhancement of phase space density that can e. . .
Date: 01/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/1999JA900445 Available at: http://onlinelibrary.wiley.com/doi/10.1029/1999JA900445
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Authors: Ukhorskiy A Y, Sitnov M I, Merkin V. G., Gkioulidou M., and Mitchell D G
Title: Ion acceleration at dipolarization fronts in the inner magnetosphere
Abstract: During geomagnetic storms plasma pressure in the inner magnetosphere is controlled by energetic ions of tens to hundreds of keV. Plasma pressure is the source of global storm time currents, which control the distribution of magnetic field and couple the inner magnetosphere and the ionosphere. Recent analysis showed that the buildup of hot ion population in the inner magnetosphere largely occurs in the form of localized discrete injections associated with sharp dipolarizations of magnetic field, similar to dipolarization fronts in the magnetotail. Because of significant differences between the ambient magnetic field and the dipolarization front properties in the magnetotail and the inner magnetosphere, the physical mechanisms of ion acceleration at dipolarization fronts in these two regions. . .
Date: 03/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023304 Available at: http://doi.wiley.com/10.1002/2016JA023304
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Authors: Min Kyungguk, Denton Richard E, Liu Kaijun, Gary Peter, and Spence Harlan E.
Title: Ion Bernstein instability as a possible source for oxygen ion cyclotron harmonic waves
Abstract: This paper demonstrates that an ion Bernstein instability can be a possible source for recently reported electromagnetic waves with frequencies at or near the singly ionized oxygen ion cyclotron frequency, inline image, and its harmonics. The particle measurements during strong wave activity revealed a relatively high concentration of oxygen ions (∼15%) whose phase space density exhibits a local peak at energy ∼20 keV. Given that the electron plasma-to-cyclotron frequency ratio is inline image, this energy corresponds to the particle speed inline image, where vA is the oxygen Alfvén speed. Using the observational key plasma parameters, a simplified ion velocity distribution is constructed, where the local peak in the oxygen ion velocity distribution is represented by an isotropic s. . .
Date: 05/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA023979 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA023979/full
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Authors: Tetrick S. S., Engebretson M. J., Posch J. L., Olson C. N., Smith C W, et al.
Title: Location of intense electromagnetic ion cyclotron (EMIC) wave events relative to the plasmapause: Van Allen Probes observations
Abstract: We have studied the spatial location relative to the plasmapause (PP) of the most intense electromagnetic ion cyclotron (EMIC) waves observed on Van Allen Probes A and B during their first full precession in local time. Most of these waves occurred over an L range of from -1 to +2 RE relative to the PP. Very few events occurred only within 0.1 RE of the PP, and events with a width in L of < 0.2 REoccurred both inside and outside the PP. Wave occurrence was always associated with high densities of ring current ions; plasma density gradients or enhancements were associated with some events but were not dominant factors in determining the sites of wave generation. Storm main and recovery phase events in the dusk sector were often inside the PP, and dayside events during quiet times and co. . .
Date: 03/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023392 Available at: http://doi.wiley.com/10.1002/2016JA023392
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Authors: Ren Jie, Zong Q. G., Miyoshi Y, Zhou X. Z., Wang Y. F., et al.
Title: Low-energy (< 200 eV) electron acceleration by ULF waves in the plasmaspheric boundary layer: Van Allen Probes observation
Abstract: We report observational evidence of cold plamsmaspheric electron (< 200 eV) acceleration by ultra-low-frequency (ULF) waves in the plasmaspheric boundary layer on 10 September 2015. Strongly enhanced cold electron fluxes in the energy spectrogram were observed along with second harmonic mode waves with a period of about 1 minute which lasted several hours during two consecutive Van Allen Probe B orbits. Cold electron (<200 eV) and energetic proton (10-20 keV) bi-directional pitch angle signatures observed during the event are suggestive of the drift-bounce resonance mechanism. The correlation between enhanced energy fluxes and ULF waves leads to the conclusions that plasmaspheric dynamics is strongly affected by ULF waves. Van Allen Probe A and B, GOES 13, GOES 15 and MMS 1 observations su. . .
Date: 08/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024316 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA024316/full
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Authors: Khazanov G. V., Boardsen S., Krivorutsky E. N., Engebretson M. J., Sibeck D., et al.
Title: Lower hybrid frequency range waves generated by ion polarization drift due to electromagnetic ion cyclotron waves: Analysis of an event observed by the Van Allen Probe B
Abstract: We analyze a wave event that occurred near noon between 07:03 and 07:08 UT on 23 February 2014 detected by the Van Allen Probes B spacecraft, where waves in the lower hybrid frequency range (LHFR) and electromagnetic ion cyclotron (EMIC) waves are observed to be highly correlated, with Pearson correlation coefficient of ~0.86. We assume that the correlation is the result of LHFR wave generation by the ions' polarization drift in the electric field of the EMIC waves. To check this assumption the drift velocities of electrons and H+, He+, and O+ ions in the measured EMIC wave electric field were modeled. Then the LHFR wave linear instantaneous growth rates for plasma with these changing drift velocities and different plasma compositions were calculated. The time distribution of these growth . . .
Date: 01/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA022814 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA022814
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Authors: Khazanov G. V., Boardsen S., Krivorutsky E. N., Engebretson M. J., Sibeck D., et al.
Title: Lower hybrid frequency range waves generated by ion polarization drift due to electromagnetic ion cyclotron waves: Analysis of an event observed by the Van Allen Probe B
Abstract: We analyze a wave event that occurred near noon between 07:03 and 07:08 UT on 23 February 2014 detected by the Van Allen Probes B spacecraft, where waves in the lower hybrid frequency range (LHFR) and electromagnetic ion cyclotron (EMIC) waves are observed to be highly correlated, with Pearson correlation coefficient of ~0.86. We assume that the correlation is the result of LHFR wave generation by the ions' polarization drift in the electric field of the EMIC waves. To check this assumption the drift velocities of electrons and H+, He+, and O+ ions in the measured EMIC wave electric field were modeled. Then the LHFR wave linear instantaneous growth rates for plasma with these changing drift velocities and different plasma compositions were calculated. The time distribution of these growth . . .
Date: 01/2017 Publisher: Journal of Geophysical Research: Space Physics Pages: 449 - 463 DOI: 10.1002/2016JA022814 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA022814/full
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Authors: Contel O., Nakamura R, Breuillard H., Argall M. R., Graham D. B., et al.
Title: Lower-hybrid drift waves and electromagnetic electron space-phase holes associated with dipolarization fronts and field-aligned currents observed by the Magnetospheric Multiscale mission during a substorm
Abstract: We analyse two ion scale dipolarization fronts associated with field-aligned currents detected by the Magnetospheric Multiscale mission during a large substorm on August 10, 2016. The first event corresponds to a fast dawnward flow with an anti-parallel current and could be generated by the wake of a previous fast earthward flow. It is associated with intense lower-hybrid drift waves detected at the front and propagating dawnward with a perpendicular phase speed close to the electric drift and the ion thermal velocity. The second event corresponds to a flow reversal: from southwward/dawnward to northward/duskward associated with a parallel current consistent with a brief expansion of the plasma sheet before the front crossing, and with a smaller lower-hybrid drift wave activity. Electromag. . .
Date: 10/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024550 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA024550/full
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Authors: Lejosne ène, Maus Stefan, and Mozer F S
Title: Model-observation comparison for the geographic variability of the plasma electric drift in the Earth's innermost magnetosphere
Abstract: Plasmaspheric rotation is known to lag behind Earth rotation. The causes for this corotation lag are not yet fully understood. We have used more than two years of Van Allen Probe observations to compare the electric drift measured below L~2 with the predictions of a general model. In the first step, a rigid corotation of the ionosphere with the solid Earth was assumed in the model. The results of the model-observation comparison are twofold: (1) radially, the model explains the average observed geographic variability of the electric drift; (2) azimuthally, the model fails to explain the full amplitude of the observed corotation lag. In the second step, ionospheric corotation was modulated in the model by thermospheric winds, as given by the latest version of the Horizontal Wind Model (HWM1. . .
Date: 07/2017 Publisher: Geophysical Research Letters DOI: 10.1002/2017GL074862 Available at: onlinelibrary.wiley.com/doi/10.1002/2017GL074862/full
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Authors: He Zhaoguo, Chen Lunjin, Zhu Hui, Xia Zhiyang, Reeves G D, et al.
Title: Multiple-satellite observation of magnetic dip event during the substorm on 10 October, 2013
Abstract: We present a multiple-satellite observation of the magnetic dip event during the substorm on October 10, 2013. The observation illustrates the temporal and spatial evolution of the magnetic dip and gives a compelling evidence that ring current ions induce the magnetic dip by enhanced plasma beta. The dip moves with the energetic ions in a comparable drift velocity and affects the dynamics of relativistic electrons in the radiation belt. In addition, the magnetic dip provides a favorable condition for the EMIC wave generation based on the linear theory analysis. The calculated proton diffusion coefficients show that the observed EMIC wave can lead to the pitch angle scattering losses of the ring current ions, which in turn partially relax the magnetic dip in the observations. This study enr. . .
Date: 09/2017 Publisher: Geophysical Research Letters DOI: 10.1002/2017GL074869 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017GL074869/full
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Authors: Turner D. L., Fennell J. F., Blake J B, Claudepierre S G, Clemmons J. H., et al.
Title: Multipoint observations of energetic particle injections and substorm activity during a conjunction between Magnetospheric Multiscale (MMS) and Van Allen Probes
Abstract: This study examines multipoint observations during a conjunction between MMS and Van Allen Probes on 07 April 2016 in which a series of energetic particle injections occurred. With complementary data from THEMIS, Geotail, and LANL-GEO (16 spacecraft in total), we develop new insights on the nature of energetic particle injections associated with substorm activity. Despite this case involving only weak substorm activity (max. AE < 300 nT) during quiet geomagnetic conditions in steady, below-average solar wind, a complex series of at least six different electron injections was observed throughout the system. Intriguingly, only one corresponding ion injection was clearly observed. All ion and electron injections were observed at < 600 keV only. MMS reveals detailed substructure within the lar. . .
Date: 09/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024554 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA024554/full
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Authors: Wang Chih-Ping, Thorne Richard, Liu Terry Z., Hartinger Michael D., Nagai Tsugunobu, et al.
Title: A multi-spacecraft event study of Pc5 ultra low frequency waves in the magnetosphere and their external drivers
Abstract: We investigate a quiet-time event of magnetospheric Pc5 ultra low frequency (ULF) waves and their likely external drivers using multiple spacecraft observations. Enhancements of electric and magnetic field perturbations in two narrow frequency bands, 1.5-2 mHz and 3.5-4 mHz, were observed over a large radial distance range from r ~5 to 11 RE. During the first half of this event, perturbations were mainly observed in the transverse components and only in the 3.5-4 mHz band. In comparison, enhancements were stronger during the second half in both transverse and compressional components and in both frequency bands. No indication of field line resonances was found for these magnetic field perturbations. Perturbations in these two bands were also observed in the magnetosheath, but not in the so. . .
Date: 04/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023610 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA023610/full
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Authors: Chu X., Bortnik J, Li W, Ma Q, Denton R., et al.
Title: A neural network model of three-dimensional dynamic electron density in the inner magnetosphere
Abstract: A plasma density model of the inner magnetosphere is important for a variety of applications including the study of wave-particle interactions, and wave excitation and propagation. Previous empirical models have been developed under many limiting assumptions and do not resolve short-term variations, which are especially important during storms. We present a three-dimensional dynamic electron density (DEN3D) model developed using a feedforward neural network with electron densities obtained from four satellite missions. The DEN3D model takes spacecraft location and time series of solar and geomagnetic indices (F10.7, SYM-H, and AL) as inputs. It can reproduce the observed density with a correlation coefficient of 0.95 and predict test data set with error less than a factor of 2. Its predict. . .
Date: 09/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024464 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA024464/full
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Authors: Breneman A. W., Crew A., Sample J., Klumpar D., Johnson A., et al.
Title: Observations Directly Linking Relativistic Electron Microbursts to Whistler Mode Chorus: Van Allen Probes and FIREBIRD II
Abstract: We present observations that provide the strongest evidence yet that discrete whistler mode chorus packets cause relativistic electron microbursts. On 20 January 2016 near 1944 UT the low Earth orbiting CubeSat Focused Investigations of Relativistic Electron Bursts: Intensity, Range, and Dynamics (FIREBIRD II) observed energetic microbursts (near L = 5.6 and MLT = 10.5) from its lower limit of 220 keV, to 1 MeV. In the outer radiation belt and magnetically conjugate, Van Allen Probe A observed rising‐tone, lower band chorus waves with durations and cadences similar to the microbursts. No other waves were observed. This is the first time that chorus and microbursts have been simultaneously observed with a separation smaller than a chorus packet. A majority of the microbursts do not have t. . .
Date: 11/2017 Publisher: Geophysical Research Letters Pages: 11,265 - 11,272 DOI: 10.1002/2017GL075001 Available at: https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2017GL075001
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Authors: Denton M. H., Reeves G. D., Larsen B. A., Friedel R. F. W., Thomsen M. F., et al.
Title: On the origin of low-energy electrons in the inner magnetosphere: Fluxes and pitch-angle distributions
Abstract: Accurate knowledge of the plasma fluxes in the inner magnetosphere is essential for both scientific and programmatic applications. Knowledge of the low-energy electrons (approximately tens to hundreds of eV) in the inner magnetosphere is particularly important since these electrons are acted upon by various physical processes, accelerating the electrons to higher energies, and also causing their loss. However, measurements of low-energy electrons are challenging, and as a result, this population has been somewhat neglected previously. This study concerns observations of low-energy electrons made by the Helium Oxygen Proton Electron instrument on board the Van Allen Probes satellites and also observations from geosynchronous orbit made by the Magnetospheric Plasma Analyzer on board Los Alam. . .
Date: 01/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023648 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA023648
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Authors: Denton M. H., Reeves G D, Larsen B A, Friedel R. F. W., Thomsen M F, et al.
Title: On the origin of low-energy electrons in the inner magnetosphere: Fluxes and pitch-angle distributions
Abstract: Accurate knowledge of the plasma fluxes in the inner magnetosphere is essential for both scientific and programmatic applications. Knowledge of the low-energy electrons (approximately tens to hundreds of eV) in the inner magnetosphere is particularly important since these electrons are acted upon by various physical processes, accelerating the electrons to higher energies, and also causing their loss. However, measurements of low-energy electrons are challenging, and as a result, this population has been somewhat neglected previously. This study concerns observations of low-energy electrons made by the Helium Oxygen Proton Electron instrument on board the Van Allen Probes satellites and also observations from geosynchronous orbit made by the Magnetospheric Plasma Analyzer on board Los Alam. . .
Date: 02/2017 Publisher: Journal of Geophysical Research: Space Physics Pages: 1789–1802 DOI: 10.1002/2016JA023648 Available at: onlinelibrary.wiley.com/doi/10.1002/2016JA023648/full
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Authors: Spence H. E., Reeves G. D., and Kessel R. L.
Title: An Overview of Early Results from the Radiation Belt Storm Probes Energetic Particle, Composition, and Thermal Plasma Suite on NASA's Van Allen Probes Mission
Abstract: N/A
Date: Publisher: Oxford University Press DOI: N/A
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Authors: Xiongdong Yu, Zhigang Yuan, Dedong Wang, Shiyong Huang, Haimeng Li, et al.
Title: Oxygen cyclotron harmonic waves observed by the Van Allen Probes
Abstract: Fine structured multiple-harmonic electromagnetic emissions at frequencies around the equatorial oxygen cyclotron harmonics are observed by Van Allen Probe A outside the core plasmasphere (L~5) off the magnetic equator (MLAT~-7.5°) during a magnetic storm. We find that the multiple-harmonic emissions have their PSD peaks at 2~8 equatorial oxygen gyro-harmonics (f~nfO+, n=2~8) while the fundamental mode (n=1) is absent, implying that the harmonic waves are generated near the equator and propagate into the observation region. Additionally these electromagnetic emissions are linear polarized. Different from the equatorial noise emission propagating very obliquely, these emissions have moderate wave normal angles (about 40°~60°) which predominately become larger as the harmonic number incre. . .
Date: 03/2017 Publisher: Science China: Earth Sciences DOI: 10.1007/s11430-016-9024-3 Available at: http://engine.scichina.com/publisher/scp/journal/SCES/doi/10.1007/s11430-016-9024-3
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Authors: Fernandes Philip A., Larsen Brian A., Thomsen Michelle F., Skoug Ruth M., Reeves Geoffrey D, et al.
Title: The plasma environment inside geostationary orbit: A Van Allen Probes HOPE survey
Abstract: The two full precessions in local time completed by the Van Allen Probes enable global specification of the near-equatorial inner magnetosphere plasma environment. Observations by the Helium-Oxygen-Proton-Electron (HOPE) mass spectrometers provide detailed insight into the global spatial distribution of electrons, H+, He+, and O+. Near-equatorial omnidirectional fluxes and abundance ratios at energies 0.1–30 keV are presented for 2 ≤ L ≤ 6 as a function of L shell, magnetic local time (MLT), and geomagnetic activity. We present a new tool built on the UBK modeling technique for classifying plasma sheet particle access to the inner magnetosphere. This new tool generates access maps for particles of constant energy for more direct comparison with in situ measurements, rather than the t. . .
Date: 08/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024160 Available at: onlinelibrary.wiley.com/doi/10.1002/2017JA024160/full
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Authors: Yang Chang, Su Zhenpeng, Xiao Fuliang, Zheng Huinan, Wang Yuming, et al.
Title: A positive correlation between energetic electron butterfly distributions and magnetosonic waves in the radiation belt slot region
Abstract: Energetic (hundreds of keV) electrons in the radiation belt slot region have been found to exhibit the butterfly pitch angle distributions. Resonant interactions with magnetosonic and whistler-mode waves are two potential mechanisms for the formation of these peculiar distributions. Here we perform a statistical study of energetic electron pitch angle distribution characteristics measured by Van Allen Probes in the slot region during a three-year period from May 2013 to May 2016. Our results show that electron butterfly distributions are closely related to magnetosonic waves rather than to whistler-mode waves. Both electron butterfly distributions and magnetosonic waves occur more frequently at the geomagnetically active times than at the quiet times. In a statistical sense, more distinct . . .
Date: 03/2017 Publisher: Geophysical Research Letters DOI: 10.1002/2017GL073116 Available at: http://doi.wiley.com/10.1002/2017GL073116
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Authors: Yu J., Li L. Y., Cao J. B., Chen L, Wang J., et al.
Title: Propagation characteristics of plasmaspheric hiss: Van Allen Probe observations and global empirical models
Abstract: Based on the Van Allen Probe A observations from 1 October 2012 to 31 December 2014, we develop two empirical models to respectively describe the hiss wave normal angle (WNA) and amplitude variations in the Earth's plasmasphere for different substorm activities. The long-term observations indicate that the plasmaspheric hiss amplitudes on the dayside increase when substorm activity is enhanced (AE index increases), and the dayside hiss amplitudes are greater than the nightside. However, the propagation angles (WNAs) of hiss waves in most regions do not depend strongly on substorm activity, except for the intense substorm-induced increase in WNAs in the nightside low L-region. The propagation angles of plasmaspheric hiss increase with increasing magnetic latitude or decreasing radial distan. . .
Date: 04/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023372 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA023372/full
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Authors: Mozer F S, Agapitov O. V., Hull A., Lejosne S., and Vasko I. Y.
Title: Pulsating auroras produced by interactions of electrons and time domain structures
Abstract: Previous evidence has suggested that either lower band chorus waves or kinetic Alfven waves scatter equatorial kilovolt electrons that propagate to lower altitudes where they precipitate or undergo further low-altitude scattering to make pulsating auroras. Recently, time domain structures (TDSs) were shown, both theoretically and experimentally, to efficiently scatter equatorial electrons. To assess the relative importance of these three mechanisms for production of pulsating auroras, 11 intervals of equatorial THEMIS data and a 4 h interval of Van Allen Probe measurements have been analyzed. During these events, lower band chorus waves produced only negligible modifications of the equatorial electron distributions. During the several TDS events, the equatorial 0.1–3 keV electrons became. . .
Date: 08/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024223 Available at: onlinelibrary.wiley.com/doi/10.1002/2017JA024223/full
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Authors: Chaston C. C., Bonnell J. W., Wygant J R, Reeves G D, Baker D N, et al.
Title: Radial transport of radiation belt electrons in kinetic field-line resonances
Abstract: A representative case study from the Van Allen Probes during a geomagnetic storm recovery phase reveals enhanced electron fluxes at intermediate pitch angles over energies from ~100 keV to 5 MeV coincident with broadband low frequency electromagnetic waves. The statistical properties of these waves are used to build a model for radial diffusion via drift-bounce resonances in kinetic Alfvén eigenmodes/kinetic field-line resonances. Estimated diffusion coefficients indicate timescales for radial transport of the order of hours in storm-time events at energies from <100 keV to MeVs over equatorial pitch angles from the edge of the loss cone to nearly perpendicular to the geomagnetic field. The correlation of kinetic resonances with electron depletions and enhancements during storm main phase. . .
Date: 07/2017 Publisher: Geophysical Research Letters DOI: 10.1002/2017GL074587 Available at: onlinelibrary.wiley.com/doi/10.1002/2017GL074587/full
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Authors: Lei Mingda, Xie Lun, Li Jinxing, Pu Zuyin, Fu Suiyan, et al.
Title: The Radiation Belt Electron Scattering by Magnetosonic Wave: Dependence on Key Parameters
Abstract: Magnetosonic (MS) waves have been found capable of creating radiation belt electron butterfly distributions in the inner magnetosphere. To investigate the physical nature of the interactions between radiation belt electrons and MS waves, and to explore a preferential condition for MS waves to scatter electrons efficiently, we performed a comprehensive parametric study of MS wave-electron interactions using test particle simulations. The diffusion coefficients simulated by varying the MS wave frequency show that the scattering effect of MS waves is frequency insensitive at low harmonics (f < 20 fcp), which has great implications on modeling the electron scattering caused by MS waves with harmonic structures. The electron scattering caused by MS waves is very sensitive to wave normal angles,. . .
Date: 12/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023801 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA023801/full
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Authors: Tang C. L., Wang Y. X., Ni B, Zhang J.-C., Reeves G D, et al.
Title: Radiation belt seed population and its association with the relativistic electron dynamics: A statistical study
Abstract: Using the particle data measured by Van Allen Probe A from October 2012 to March 2016, we investigate in detail the radiation belt seed population and its association with the relativistic electron dynamics during 74 geomagnetic storms. The period of the storm recovery phase was limited to 72 h. The statistical study shows that geomagnetic storms and substorms play important roles in the radiation belt seed population (336 keV electrons) dynamics. Based on the flux changes of 1 MeV electrons before and after the storm peak, these storm events are divided into two groups of “large flux enhancement” and “small flux enhancement.” For large flux enhancement storm events, the correlation coefficients between the peak flux location of the seed population and those of relativistic electro. . .
Date: 05/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA023905 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA023905/full
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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: 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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