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Van Allen Probes Bibliography is from August 2012 through September 2021 Notice:
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Found 59 entries in the Bibliography.
Showing entries from 1 through 50
| 2021 |
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Abstract Reconstruction and prediction of the state of the near-Earth space environment is important for anomaly analysis, development of empirical models and understanding of physical processes. Accurate reanalysis or predictions that account for uncertainties in the associated model and the observations, can be obtained by means of data assimilation. The ensemble Kalman filter (EnKF) is one of the most promising filtering tools for non-linear and high dimensional systems in the context of terrestrial weather prediction. In ... Tibocha, A.; de Wiljes, J.; Shprits, Y; Aseev, N.; Published by: Space Weather Published on: 08/2021 YEAR: 2021 DOI: https://doi.org/10.1029/2020SW002672 Kalman Filter; Ensemble Kalman filter; forecasting; Van Allen Probes |
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A Comparison of Radial Diffusion Coefficients in 1-D and 3-D Long-Term Radiation Belt Simulations AbstractRadial diffusion is one of the dominant physical mechanisms driving acceleration and loss of radiation belt electrons. A number of parameterizations for radial diffusion coefficients have been developed, each differing in the dataset used. Here, we investigate the performance of different parameterizations by Brautigam and Albert (2000), Brautigam et al. (2005), Ozeke et al. (2014), Ali et al. (2015); Ali et al. (2016); Ali (2016), and Liu et al. (2016) on long-term radiation belt modeling using the Versatile El ... Drozdov, A; Allison, H.; Shprits, Y; Elkington, S.R.; Aseev, N.A.; Published by: Journal of Geophysical Research: Space Physics Published on: 07/2021 YEAR: 2021 DOI: https://doi.org/10.1029/2020JA028707 Radiation belts; radial diffusion; VERB code; Van Allen Probes |
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Abstract Following the end of the Van Allen Probes mission, the Arase satellite offers a unique opportunity to continue in-situ radiation belt and ring current particle measurements into the next solar cycle. In this study we compare spin-averaged flux measurements from the MEPe, HEP-L, HEP-H, and XEP-SSD instruments on Arase with those from the MagEIS and REPT instruments on the Van Allen Probes, calculating Pearson correlation coefficient and the mean ratio of fluxes at L* conjunctions between the spacecraft. Arase and Van ... Szabó-Roberts, Mátyás; Shprits, Yuri; Allison, Hayley; Vasile, Ruggero; Smirnov, Artem; Aseev, Nikita; Drozdov, Alexander; Miyoshi, Yoshizumi; Claudepierre, Seth; Kasahara, Satoshi; Yokota, Shoichiro; Mitani, Takefumi; Takashima, Takeshi; Higashio, Nana; Hori, Tomo; Keika, Kunihiro; Imajo, Shun; Shinohara, Iku; Published by: Journal of Geophysical Research: Space Physics Published on: 06/2021 YEAR: 2021 DOI: https://doi.org/10.1029/2020JA028929 |
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A Comparison of the Location of the Mid-latitude Trough and Plasmapause Boundary Abstract We have compared the location of the mid-latitude trough observed in two dimensional vertical total electron content (vTEC) maps with four plasmapause boundary models, Radiation Belt Storm Probes observations, and IMAGE EUV observations all mapped to the ionosphere pierce point using the Tsyganenko [1996] magnetic field line model. For this study we examine four events over North America: one just after the 13 October 2012 storm, one during the 20 April 2002 double storm, another during a large substorm on 26 Januar ... Weygand, J.M.; Zhelavskaya, I.; Shprits, Y.; Published by: Journal of Geophysical Research: Space Physics Published on: 03/2021 YEAR: 2021 DOI: https://doi.org/10.1029/2020JA028213 mid-latitude trough; plasmapause boundary; vTECs; plasmapause models; Van Allen Probes |
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Reconstruction of the Radiation Belts for Solar Cycles 17 – 24 (1933 – 2017) AbstractWe present a reconstruction of the dynamics of the radiation belts from Solar Cycles 17 – 24 which allows us to study how radiation belt activity has varied between the different solar cycles. The radiation belt simulations are produced using the Versatile Electron Radiation Belt (VERB)-3D code. The VERB-3D code simulations incorporate radial, energy, and pitch angle diffusion to reproduce the radiation belts. Our simulations use the historical measurements of Kp (available since Solar Cycle 17, i.e., 1933) to mode ... Saikin, A.; Shprits, Y; Drozdov, A; Landis, D.; Zhelavskaya, I.; Cervantes, S.; Published by: Space Weather Published on: 02/2021 YEAR: 2021 DOI: https://doi.org/10.1029/2020SW002524 Radiation belts; numerical modeling; Particle acceleration; Magnetosphere: inner; forecasting; Van Allen Probes |
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A combined neural network- and physics-based approach for modeling plasmasphere dynamics AbstractIn recent years, feedforward neural networks (NNs) have been successfully applied to reconstruct global plasmasphere dynamics in the equatorial plane. These neural network-based models capture the large-scale dynamics of the plasmasphere, such as plume formation and erosion of the plasmasphere on the nightside. However, their performance depends strongly on the availability of training data. When the data coverage is limited or non-existent, as occurs during geomagnetic storms, the performance of NNs significantly de ... Zhelavskaya, I.; Aseev, N.; Shprits, Y; Published by: Journal of Geophysical Research: Space Physics Published on: 02/2021 YEAR: 2021 DOI: https://doi.org/10.1029/2020JA028077 plasmasphere; plasma density; neural networks; data assimilation; Kalman Filter; Machine learning; Van Allen Probes |
| 2020 |
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In this study we investigate two distinct loss mechanisms responsible for the rapid dropouts of radiation belt electrons by assimilating data from Van Allen Probes A and B and Geostationary Operational Environmental Satellites (GOES) 13 and 15 into a 3-D diffusion model. In particular, we examine the respective contribution of electromagnetic ion cyclotron (EMIC) wave scattering and magnetopause shadowing for values of the first adiabatic invariant μ ranging from 300 to 3,000 MeV G−1. We inspect the innovation vector ... Cervantes, S.; Shprits, Y; Aseev, N.; Allison, H.; Published by: Journal of Geophysical Research: Space Physics Published on: 08/2020 YEAR: 2020 DOI: https://doi.org/10.1029/2020JA028208 data assimilation; EMIC waves; magnetopause shadowing; innovation vector; Kalman Filter; radiation belt losses; Van Allen Probes |
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In this study, we performed a series of long-term and individual storm simulations with and without hiss, chorus, and electromagnetic ion cyclotron (EMIC) waves. We compared simulation results incorporating different wave modes with Van Allen Probes flux observations to illustrate how hiss and chorus waves aid EMIC waves in depleting multi-MeV electrons. We found that EMIC, hiss, and chorus waves are required to reproduce satellite measurements in our simulations. Our results indicate that hiss waves play a dominant role in ... Drozdov, A; Usanova, M.; Hudson, M.; Allison, H.; Shprits, Y; Published by: Journal of Geophysical Research: Space Physics Published on: 08/2020 YEAR: 2020 DOI: https://doi.org/10.1029/2020JA028282 EMIC waves; Radiation belts; Whistler waves; VERB code; Fokker-Planck diffusion equation; Van Allen Probes |
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Bayesian Inference of Quasi-Linear Radial Diffusion Parameters using Van Allen Probes Abstract The Van Allen radiation belts in the magnetosphere have been extensively studied using models based on radial diffusion theory, which is derived from a quasi-linear approach with prescribed inner and outer boundary conditions. The 1D diffusion model requires the knowledge of a diffusion coefficient and an electron loss timescale, which is typically parameterized in terms of various quantities such as the spatial (L) coordinate or a geomagnetic index (e.g., Kp). These terms are typically empirically derived, not dire ... Sarma, Rakesh; Chandorkar, Mandar; Zhelavskaya, Irina; Shprits, Yuri; Drozdov, Alexander; Camporeale, Enrico; Published by: Journal of Geophysical Research: Space Physics Published on: 04/2020 YEAR: 2020 DOI: 10.1029/2019JA027618 radial diffusion; Magnetosphere; Bayesian inference; Van Allen radiation belt; Van Allen Probes |
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Quantifying the Effect of Plasmaspheric Hiss on the Electron Loss from the Slot Region Abstract We present global statistical models of both wave amplitude and wave normal angle (WNA) of plasmaspheric hiss using Van Allen Probe-A observations. They utilize the time history of solar wind parameters, i.e., interplanetary magnetic field BZ and solar wind speed, and the AE index for each measurement of hiss waves as inputs. The solar wind parameter-based model generally results in higher performance than using only the AE index as an input. Both observations and model results reveal a clear dependence of hiss wave ... Kim, Kyung-Chan; Shprits, Yuri; Wang, Dedong; Published by: Journal of Geophysical Research: Space Physics Published on: 04/2020 YEAR: 2020 DOI: 10.1029/2019JA027555 Plasmaspheric Hiss; Van Allen Probes; Electron slot region; Statistical modeling; Diffusion simulation; Wave-particle interaction |
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The Effect of Plasma Boundaries on the Dynamic Evolution of Relativistic Radiation Belt Electrons Abstract Understanding the dynamic evolution of relativistic electrons in the Earth s radiation belts during both storm and nonstorm times is a challenging task. The U.S. National Science Foundation s Geospace Environment Modeling (GEM) focus group “Quantitative Assessment of Radiation Belt Modeling” has selected two storm time and two nonstorm time events that occurred during the second year of the Van Allen Probes mission for in-depth study. Here, we perform simulations for these GEM challenge events using the 3D Versa ... Wang, Dedong; Shprits, Yuri; Zhelavskaya, Irina; Effenberger, Frederic; Castillo, Angelica; Drozdov, Alexander; Aseev, Nikita; Cervantes, Sebastian; Published by: Journal of Geophysical Research: Space Physics Published on: 04/2020 YEAR: 2020 DOI: 10.1029/2019JA027422 Radiation belt; simulation; relativistic electrons; magnetopause shadowing; Wave-particle interaction; Plasmapause; Van Allen Probes |
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Bayesian Inference of Quasi-Linear Radial Diffusion Parameters using Van Allen Probes The Van Allen radiation belts in the magnetosphere have been extensively studied using models based on radial diffusion theory, which is derived from a quasi-linear approach with prescribed inner and outer boundary conditions. The 1D diffusion model requires the knowledge of a diffusion coefficient and an electron loss timescale, which is typically parameterized in terms of various quantities such as the spatial (L) coordinate or a geomagnetic index (e.g., Kp). These terms are typically empirically derived, not directly meas ... Sarma, Rakesh; Chandorkar, Mandar; Zhelavskaya, Irina; Shprits, Yuri; Drozdov, Alexander; Camporeale, Enrico; Published by: Journal of Geophysical Research: Space Physics Published on: 04/2020 YEAR: 2020 DOI: https://doi.org/10.1029/2019JA027618 radial diffusion; Magnetosphere; Bayesian inference; Van Allen radiation belt; Van Allen Probes |
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Quantifying the Effect of Plasmaspheric Hiss on the Electron Loss From the Slot Region We present global statistical models of both wave amplitude and wave normal angle (WNA) of plasmaspheric hiss using Van Allen Probe-A observations. They utilize the time history of solar wind parameters, that is, interplanetary magnetic field BZ and solar wind speed, and the AE index for each measurement of hiss waves as inputs. The solar wind parameter-based model generally results in higher performance than using only the AE index as an input. Both observations and model results reveal a clear dependence of hiss wave distr ... Kim, Kyung-Chan; Shprits, Yuri; Wang, Dedong; Published by: Journal of Geophysical Research: Space Physics Published on: 04/2020 YEAR: 2020 DOI: https://doi.org/10.1029/2019JA027555 Plasmaspheric Hiss; Van Allen Probes; Electron slot region; Statistical modeling; Diffusion simulation; Wave-particle interaction |
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The Effect of Plasma Boundaries on the Dynamic Evolution of Relativistic Radiation Belt Electrons Understanding the dynamic evolution of relativistic electrons in the Earth s radiation belts during both storm and nonstorm times is a challenging task. The U.S. National Science Foundation s Geospace Environment Modeling (GEM) focus group “Quantitative Assessment of Radiation Belt Modeling” has selected two storm time and two nonstorm time events that occurred during the second year of the Van Allen Probes mission for in-depth study. Here, we perform simulations for these GEM challenge events using the 3D Versatile Elec ... Wang, Dedong; Shprits, Yuri; Zhelavskaya, Irina; Effenberger, Frederic; Castillo, Angelica; Drozdov, Alexander; Aseev, Nikita; Cervantes, Sebastian; Published by: Journal of Geophysical Research: Space Physics Published on: 04/2020 YEAR: 2020 DOI: https://doi.org/10.1029/2019JA027422 Radiation belt; simulation; relativistic electrons; magnetopause shadowing; Wave-particle interaction; Plasmapause; Van Allen Probes |
| 2019 |
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Storm Time Depletions of Multi-MeV Radiation Belt Electrons Observed at Different Pitch Angles During geomagnetic storms, the rapid depletion of the high-energy (several MeV) outer radiation belt electrons is the result of loss to the interplanetary medium through the magnetopause, outward radial diffusion, and loss to the atmosphere due to wave-particle interactions. We have performed a statistical study of 110 storms using pitch angle resolved electron flux measurements from the Van Allen Probes mission and found that inside of the radiation belt (L* = 3 - 5) the number of storms that result in depletion of electron ... Drozdov, A; Aseev, N.; Effenberger, F.; Turner, D.; Saikin, A.; Shprits, Y; Published by: Journal of Geophysical Research: Space Physics Published on: 11/2019 YEAR: 2019 DOI: 10.1029/2019JA027332 EMIC waves; multi-MeV electrons; Radiation belts; Van Allen Probes |
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In this study, rapid loss of relativistic radiation belt electrons at low L* values (2.4\textendash3.2) during a strong geomagnetic storm on 22 June 2015 is investigated along with five possible loss mechanisms. Both the particle and wave data are obtained from the Van Allen Probes. Duskside H+ band electromagnetic ion cyclotron (EMIC) waves were observed during a rapid decrease of relativistic electrons with energy above 5.2 MeV occurring outside the plasmasphere during extreme magnetopause compression. Lower He+ compositio ... Qin, Murong; Hudson, Mary; Li, Zhao; Millan, Robyn; Shen, Xiaochen; Shprits, Yuri; Woodger, Leslie; Jaynes, Allison; Kletzing, Craig; Published by: Journal of Geophysical Research: Space Physics Published on: 05/2019 YEAR: 2019 DOI: 10.1029/2018JA025726 cold ion composition; EMIC wave; minimum resonant energy; pitch angle diffusion; quasi-linear theory; relativistic electron loss; Van Allen Probes |
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Modulation of Locally Generated Equatorial Noise by ULF Wave In this paper we report a rare and fortunate event of fast magnetosonic (MS, also called equatorial noise) waves modulated by compressional ultralow frequency (ULF) waves measured by Van Allen Probes. The characteristics of MS waves, ULF waves, proton distribution, and their potential correlations are analyzed. The results show that ULF waves can modulate the energetic ring proton distribution and in turn modulate the MS generation. Furthermore, the variation of MS intensities is attributed to not only ULF wave activities bu ... Zhu, Hui; Chen, Lunjin; Liu, Xu; Shprits, Yuri; Published by: Journal of Geophysical Research: Space Physics Published on: 04/2019 YEAR: 2019 DOI: 10.1029/2018JA026199 linear growth rate; magnetosonic waves; Radiation belts; ULF waves; Van Allen Probes |
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Published by: Space Weather Published on: 04/2019 YEAR: 2019 DOI: 10.1029/2018SW002110 data assimilation; inner magnetosphere; Kalman Filter; Reanalysis; ring current; Van Allen Probes |
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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 convec ... Published by: Space Weather Published on: 04/2019 YEAR: 2019 DOI: 10.1029/2018SW002110 data assimilation; inner magnetosphere; Kalman Filter; Reanalysis; ring current; Van Allen Probes |
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Statistical Analysis of Hiss Waves in Plasmaspheric Plumes Using Van Allen Probe Observations Plasmaspheric hiss waves commonly observed in high-density regions in the Earth\textquoterights magnetosphere are known to be one of the main contributors to the loss of radiation belt electrons. There has been a lot of effort to investigate the distributions of hiss waves in the plasmasphere, while relatively little attention has been given to those in the plasmaspheric plume. In this study, we present for the first time a statistical analysis of the occurrence and the spatial distribution of wave amplitudes and wave normal ... Kim, Kyung-Chan; Shprits, Yuri; Published by: Journal of Geophysical Research: Space Physics Published on: 03/2019 YEAR: 2019 DOI: 10.1029/2018JA026458 |
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The dynamics of Van Allen belts revisited Shprits, Yuri; Horne, Richard; Kellerman, Adam; Drozdov, Alexander; Published by: Nature Physics Published on: 02/2019 YEAR: 2019 DOI: 10.1038/nphys4350 |
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The Cluster mission, launched in 2000, has produced a large database of electron flux intensity measurements in the Earth\textquoterights magnetosphere by the Research with Adaptive Particle Imaging Detector (RAPID)/ Imaging Electron Spectrometer (IES) instrument. However, due to background contamination of the data with high-energy electrons (<400 keV) and inner-zone protons (230-630 keV) in the radiation belts and ring current, the data have been rarely used for inner-magnetospheric science. The current paper presents two ... Smirnov, A.; Kronberg, E.; Latallerie, F.; Daly, P.; Aseev, N.; Shprits, Y; Kellerman, A.; Kasahara, S.; Turner, D.; Taylor, M.; Published by: Space Weather Published on: 02/2019 YEAR: 2019 DOI: 10.1029/2018SW001989 electrons; Radiation belts; Solar Cycle; Space weather; Van Allen Probes |
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Electromagnetic ion cyclotron waves have long been recognized to play a crucial role in the dynamic loss of ring current protons. While the field-aligned propagation approximation of electromagnetic ion cyclotron waves was widely used to quantify the scattering loss of ring current protons, in this study, we find that the wave normal distribution strongly affects the pitch angle scattering efficiency of protons. Increase of peak normal angle or angular width can considerably reduce the scattering rates of <=10 keV protons. F ... Cao, Xing; Ni, Binbin; Summers, Danny; Shprits, Yuri; Gu, Xudong; Fu, Song; Lou, Yuequn; Zhang, Yang; Ma, Xin; Zhang, Wenxun; Huang, He; Yi, Juan; Published by: Geophysical Research Letters Published on: 01/2019 YEAR: 2019 DOI: 10.1029/2018GL081550 EMIC waves; Quasi-linear diffusion; Ring current protons; Van Allen Probes; wave-particle interactions |
| 2018 |
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The evolution of the radiation belts in L-shell (L), energy (E), and equatorial pitch-angle (α0) is analyzed during the calm 11-day interval (March 4 \textendashMarch 15) following the March 1 storm 2013. Magnetic Electron and Ion Spectrometer (MagEIS) observations from Van Allen Probes are interpreted alongside 1D and 3D Fokker-Planck simulations combined with consistent event-driven scattering modeling from whistler mode hiss waves. Three (L, E, α0)-regions persist through 11 days of hiss wave scattering; the pitch-angle ... Ripoll, -F.; Loridan, V.; Denton, M.; Cunningham, G.; Reeves, G.; ik, O.; Fennell, J.; Turner, D.; Drozdov, A; Villa, J.; Shprits, Y; Thaller, S.; Kurth, W.; Kletzing, C.; Henderson, M.; Ukhorskiy, A; Published by: Journal of Geophysical Research: Space Physics Published on: 12/2018 YEAR: 2018 DOI: 10.1029/2018JA026111 electron lifetime; hiss waves; pitch-angle diffusion coefficient; Radiation belts; Van Allen Probes; wave particle interactions |
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Whistler mode exohiss are the structureless hiss waves observed outside the plasmapause with featured equatorward Poynting flux. An event of the amplification of exohiss as well as chorus waves was recorded by Van Allen Probes during the recovery phase of a weak geomagnetic storm. Amplitudes of both types of the waves showed a significant increase at the regions of electron density enhancements. It is found that the electrons resonant with exohiss and chorus showed moderate pitch-angle anisotropies. The ratio of the number o ... Zhu, Hui; Shprits, Yuri; Chen, Lunjin; Liu, Xu; Kellerman, Adam; Published by: Journal of Geophysical Research: Space Physics Published on: 10/2018 YEAR: 2018 DOI: 10.1029/2017JA025023 electromagnetic waves; Exohiss; linear theory; Radiation belts; Van Allen Probes |
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We perform a statistical study calculating electromagnetic ion cyclotron (EMIC) wave amplitudes based off in situ plasma measurements taken by the Van Allen Probes\textquoteright (1.1\textendash5.8 Re) Helium, Oxygen, Proton, Electron (HOPE) instrument. Calculated wave amplitudes are compared to EMIC waves observed by the Electric and Magnetic Field Instrument Suite and Integrated Science on board the Van Allen Probes during the same period. The survey covers a 22-month period (1 November 2012 to 31 August 2014), a full Van ... Saikin, A.A.; Jordanova, V.K.; Zhang, J.C.; Smith, C.W.; Spence, H.E.; Larsen, B.A.; Reeves, G.D.; Torbert, R.B.; Kletzing, C.A.; Zhelavskaya, I.S.; Shprits, Y.Y.; Published by: Journal of Atmospheric and Solar-Terrestrial Physics Published on: 02/2018 YEAR: 2018 DOI: 10.1016/j.jastp.2018.01.024 EMIC waves Van Allen Probes Linear theory Wave generation; Van Allen Probes |
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Survey of the Favorable Conditions for Magnetosonic Wave Excitation The ratio of the proton ring velocity (VR) to the local Alfven speed (VA), in addition to proton ring distributions, plays a key factor in the excitation of magnetosonic waves at frequencies between the proton cyclotron frequency fcp and the lower hybrid resonance frequency fLHR in the Earth\textquoterights magnetosphere. Here we investigate whether there is a statistically significant relationship between occurrences of proton rings and magnetosonic waves both outside and inside the plasmapause using particle and wave data ... Kim, Kyung-Chan; Shprits, Yuri; Published by: Journal of Geophysical Research: Space Physics Published on: 01/2018 YEAR: 2018 DOI: 10.1002/2017JA024865 magnetosonic equatorial noise; proton ring distribution; Van Allen Probes |
| 2017 |
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Empirical modeling of the plasmasphere dynamics using neural networks 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 distributi ... Zhelavskaya, Irina; Shprits, Yuri; c, Maria; Published by: Journal of Geophysical Research: Space Physics Published on: 10/2017 YEAR: 2017 DOI: 10.1002/2017JA024406 inner magnetosphere; Machine learning; Models; neural networks; plasmasphere; Van Allen Probes |
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Up until recently, signatures of the ultrarelativistic electron loss driven by electromagnetic ion cyclotron (EMIC) waves in the Earth\textquoterights outer radiation belt have been limited to direct or indirect measurements of electron precipitation or the narrowing of normalized pitch angle distributions in the heart of the belt. In this study, we demonstrate additional observational evidence of ultrarelativistic electron loss that can be driven by resonant interaction with EMIC waves. We analyzed the profiles derived from ... Aseev, N.; Shprits, Y; Drozdov, A; Kellerman, A.; Usanova, M.; Wang, D.; Zhelavskaya, I.; Published by: Journal of Geophysical Research: Space Physics Published on: 09/2017 YEAR: 2017 DOI: 10.1002/2017JA024485 electron loss; EMIC waves; Radiation belts; ultrarelativistic electrons; Van Allen Probes; wave-particle interactions |
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EMIC wave parameterization in the long-term VERB code simulation Electromagnetic ion cyclotron (EMIC) waves play an important role in the dynamics of ultrarelativistic electron population in the radiation belts. However, as EMIC waves are very sporadic, developing a parameterization of such wave properties is a challenging task. Currently, there are no dynamic, activity-dependent models of EMIC waves that can be used in the long-term (several months) simulations, which makes the quantitative modeling of the radiation belt dynamics incomplete. In this study, we investigate Kp, Dst, and AE ... Drozdov, A; Shprits, Y; Usanova, M.; Aseev, N.; Kellerman, A.; Zhu, H.; Published by: Journal of Geophysical Research: Space Physics Published on: 08/2017 YEAR: 2017 DOI: 10.1002/2017JA024389 |
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We present the dependence of the magnetosonic wave amplitudes both outside and inside the plasmapause on the solar wind and AE index using Van Allen Probe-A spacecraft during the time period of 1 October 2012 to 31 December 2015, based on a correlation and regression analysis. Solar wind parameters considered are the southward interplanetary magnetic field (IMF BS), solar wind number density (NSW), and bulk speed (VSW). We find that the wave amplitudes outside (inside) the plasmapause are well correlated with the preceding A ... Kim, Kyung-Chan; Shprits, Yuri; Published by: Journal of Geophysical Research: Space Physics Published on: 05/2017 YEAR: 2017 DOI: 10.1002/2017JA024094 magnetosonic equatorial noise; solar wind dependence; Van Allen Probes |
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Radial diffusion is one of the dominant physical mechanisms that drives acceleration and loss of the radiation belt electrons, which makes it very important for nowcasting and forecasting space weather models. We investigate the sensitivity of the two parameterizations of the radial diffusion of Brautigam and Albert (2000) and Ozeke et al. (2014) on long-term radiation belt modeling using the Versatile Electron Radiation Belt (VERB). Following Brautigam and Albert (2000) and Ozeke et al. (2014), we first perform 1-D radial d ... Drozdov, A; Shprits, Y; Aseev, N.; Kellerman, A.; Reeves, G.; Published by: Space Weather Published on: 01/2017 YEAR: 2017 DOI: 10.1002/swe.v15.110.1002/2016SW001426 radial diffusion; Radiation belts; Van Allen Probes; VERB code |
| 2016 |
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Statistical Properties of the Radiation Belt Seed Population We present a statistical analysis of phase space density data from the first 26 months of the Van Allen Probes mission. In particular we investigate the relationship between the 10s-100s keV seed electrons and >1 MeV core radiation belt electron population. Using a cross correlation analysis, we find that the seed and core populations are well correlated with a coefficient of ≈ 0.73 with a time lag of 10-15 hours. We present evidence of a seed population threshold that is necessary for subsequent acceleration. The depth of ... Boyd, A.J.; Spence, H.E.; Huang, C.-L.; Reeves, G.; Baker, D.; Turner, D.L.; Claudepierre, S.; Fennell, J.; Blake, J.; Shprits, Y.Y.; Published by: Journal of Geophysical Research: Space Physics Published on: 07/2016 YEAR: 2016 DOI: 10.1002/2016JA022652 Phase space density; Radiation belt; seed population; Van Allen Probes |
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On the Time Needed to Reach an Equilibrium Structure of the Radiation Belts In this study, we complement the notion of equilibrium states of the radiation belts with a discussion on the dynamics and time needed to reach equilibrium. We solve for the equilibrium states obtained using 1D radial diffusion with recently developed hiss and chorus lifetimes at constant values of Kp = 1, 3 and 6. We find that the equilibrium states at moderately low Kp, when plotted vs L-shell (L) and energy (E), display the same interesting S-shape for the inner edge of the outer belt as recently observed by the Van Allen ... Ripoll, J.; Loridan, V.; Cunningham, G.; Reeves, G.; Shprits, Y; Published by: Journal of Geophysical Research: Space Physics Published on: 06/2016 YEAR: 2016 DOI: 10.1002/2015JA022207 |
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We present the Neural-network-based Upper hybrid Resonance Determination (NURD) algorithm for automatic inference of the electron number density from plasma wave measurements made on board NASA\textquoterights Van Allen Probes mission. A feedforward neural network is developed to determine the upper hybrid resonance frequency, fuhr, from electric field measurements, which is then used to calculate the electron number density. In previous missions, the plasma resonance bands were manually identified, and there have been few a ... Zhelavskaya, I.; Spasojevic, M.; Shprits, Y; Kurth, W.; Published by: Journal of Geophysical Research: Space Physics Published on: 05/2016 YEAR: 2016 DOI: 10.1002/2015JA022132 |
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New global loss model of energetic and relativistic electrons based on Van Allen Probes measurements Energetic electron observations in Earth\textquoterights radiation belts are typically sparse and multi-point studies often rely on serendipitous conjunctions. This paper establishes the scientific utility of the Combined X-ray Dosimeter (CXD), currently flown on 19 satellites in the Global Positioning System (GPS) constellation, by cross-calibrating energetic electron measurements against data from the Van Allen Probes. By breaking our cross-calibration into two parts \textendash one that removes any spectral assumptions fr ... Orlova, Ksenia; Shprits, Yuri; Spasojevic, Maria; Published by: Journal of Geophysical Research: Space Physics Published on: 02/2016 YEAR: 2016 DOI: 10.1002/2015JA021878 |
| 2015 |
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Global Empirical Models of Plasmaspheric Hiss using Van Allen Probes Plasmaspheric hiss is a whistler mode emission that permeates the Earth\textquoterights plasmasphere and is a significant driver of energetic electron losses through cyclotron-resonant pitch angle scattering. The EMFISIS instrument on the Van Allen Probes mission provides vastly improved measurements of the hiss wave environment including continuous measurements of the wave magnetic field cross-spectral matrix and enhanced low frequency coverage. Here, we develop empirical models of hiss wave intensity using two years of Van ... Spasojevic, M.; Shprits, Y.Y.; Orlova, K.; Published by: Journal of Geophysical Research: Space Physics Published on: 11/2015 YEAR: 2015 DOI: 10.1002/2015JA021803 Electron scattering; Empirical Model; inner magnetosphere; Plasmaspheric Hiss; Van Allen Probes |
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This study is focused on understanding the coupling between different electron populations in the inner magnetosphere and the various physical processes that determine evolution of electron fluxes at different energies. Observations during the March 17, 2013 storm and simulations with a newly developed Versatile Electron Radiation Belt-4D (VERB-4D) are presented. Analysis of the drift trajectories of the energetic and relativistic electrons shows that electron trajectories at transitional energies with a first invariant on t ... Shprits, Yuri; Kellerman, Adam; Drozdov, Alexander; Spense, Harlan; Reeves, Geoffrey; Baker, Daniel; Published by: Geophysical Research Letters Published on: 09/2015 YEAR: 2015 DOI: 10.1002/2015GL065230 inner magnetosphere; numerical simulations; Radiation belts; ring current; Van Allen Probes; wave-particle interactions |
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The third Inner Magnetosphere Coupling (IMC III) workshop was held March 2015 at University of California, Los Angeles. The workshop included extensive discussion of space weather and applications bring together scientists from the solar wind, magnetosphere and ionospheric communities as well as space weather stakeholders and researchers focusing on translational research and applications in industry. Published by: Space Weather Published on: 08/2015 YEAR: 2015 DOI: 10.1002/2015SW001295 |
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In this study, we compare long-term simulations performed by the Versatile Electron Radiation Belt (VERB) code with observations from the MagEIS and REPT instruments on the Van Allen Probes satellites. The model takes into account radial, energy, pitch-angle and mixed diffusion, losses into the atmosphere, and magnetopause shadowing. We consider the energetic (>100 keV), relativistic (~0.5-1 MeV) and ultra-relativistic (>2 MeV) electrons. One year of relativistic electron measurements (μ=700 MeV/G) from October 1, 2012 to O ... Drozdov, A; Shprits, Y; Orlova, K.G.; Kellerman, A.; Subbotin, D.; Baker, D.; Spence, H.E.; Published by: Journal of Geophysical Research: Space Physics Published on: 04/2015 YEAR: 2015 DOI: 10.1002/2014JA020637 EMIC waves; Long-term simulation; Van Allen Probes; VERB code |
| 2014 |
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Characterization of the energy-dependent response of riometer absorption Ground based riometers provide an inexpensive means to continuously remote sense the precipitation of electrons in the dynamic auroral region of Earth\textquoterights ionosphere. The energy-dependent relationship between riometer absorption and precipitating electrons is thus of great importance for understanding the loss of electrons from the Earth\textquoterights magnetosphere. In this study, statistical and event-based analyses are applied to determine the energy of electrons to which riometers chiefly respond. Time-lagge ... Kellerman, A.; Shprits, Y; Makarevich, R.; Spanswick, E.; Donovan, E.; Reeves, G.; Published by: Journal of Geophysical Research: Space Physics Published on: 11/2014 YEAR: 2014 DOI: 10.1002/2014JA020027 cosmic noise absorption; electron energy; particle modeling; Radiation belts; riometer; electron precipitation |
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Simulation of high-energy radiation belt electron fluxes using NARMAX-VERB coupled codes This study presents a fusion of data-driven and physics-driven methodologies of energetic electron flux forecasting in the outer radiation belt. Data-driven NARMAX (Nonlinear AutoRegressive Moving Averages with eXogenous inputs) model predictions for geosynchronous orbit fluxes have been used as an outer boundary condition to drive the physics-based Versatile Electron Radiation Belt (VERB) code, to simulate energetic electron fluxes in the outer radiation belt environment. The coupled system has been tested for three extende ... Pakhotin, I.; Drozdov, A; Shprits, Y; Boynton, R.; Subbotin, D.; Balikhin, M.; Published by: Journal of Geophysical Research: Space Physics Published on: 10/2014 YEAR: 2014 DOI: 10.1002/2014JA020238 |
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Survey analysis of chorus intensity at Saturn In order to conduct theoretical studies or modeling of pitch angle scattering of electrons by whistler mode chorus emission at Saturn, a knowledge of chorus occurrence and magnetic intensity levels, PB, as well as the distribution of PB relative to frequency and spatial parameters is essential. In this paper an extensive survey of whistler mode magnetic intensity levels at Saturn is carried out, and Gaussian fits of PB are performed. We fit the spectrum of wave magnetic intensity between the lower hybrid frequency and fceq/2 ... Menietti, J.; Averkamp, T.; Groene, J.; Horne, R.; Shprits, Y; Woodfield, E.; Hospodarsky, G.; Gurnett, D.; Published by: Journal of Geophysical Research: Space Physics Published on: 10/2014 YEAR: 2014 DOI: 10.1002/jgra.v119.1010.1002/2014JA020523 |
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We study the effect of electromagnetic ion cyclotron (EMIC) waves on the loss and pitch angle scattering of relativistic and ultrarelativistic electrons during the recovery phase of a moderate geomagnetic storm on 11 October 2012. The EMIC wave activity was observed in situ on the Van Allen Probes and conjugately on the ground across the Canadian Array for Real-time Investigations of Magnetic Activity throughout an extended 18 h interval. However, neither enhanced precipitation of >0.7 MeV electrons nor reductions in Van All ... Usanova, M.; Drozdov, A.; Orlova, K.; Mann, I.; Shprits, Y.; Robertson, M.; Turner, D.; Milling, D.; Kale, A.; Baker, D.; Thaller, S.; Reeves, G.; Spence, H.; Kletzing, C.; Wygant, J.; Published by: Geophysical Research Letters Published on: 03/2014 YEAR: 2014 DOI: 10.1002/2013GL059024 |
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The dual-spacecraft Van Allen Probes mission has provided a new window into mega electron volt (MeV) particle dynamics in the Earth\textquoterights radiation belts. Observations (up to E ~10 MeV) show clearly the behavior of the outer electron radiation belt at different timescales: months-long periods of gradual inward radial diffusive transport and weak loss being punctuated by dramatic flux changes driven by strong solar wind transient events. We present analysis of multi-MeV electron flux and phase space density (PSD) ch ... Baker, D.; Jaynes, A.; Li, X.; Henderson, M.; Kanekal, S.; Reeves, G.; Spence, H.; Claudepierre, S.; Fennell, J.; Hudson, M.; Thorne, R.; Foster, J.; Erickson, P.; Malaspina, D.; Wygant, J.; Boyd, A.; Kletzing, C.; Drozdov, A.; Shprits, Y; Published by: Geophysical Research Letters Published on: 03/2014 YEAR: 2014 DOI: 10.1002/2013GL058942 |
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On 17 March 2013, a large magnetic storm significantly depleted the multi-MeV radiation belt. We present multi-instrument observations from the Van Allen Probes spacecraft Radiation Belt Storm Probe A and Radiation Belt Storm Probe B at ~6 Re in the midnight sector magnetosphere and from ground-based ionospheric sensors during a substorm dipolarization followed by rapid reenergization of multi-MeV electrons. A 50\% increase in magnetic field magnitude occurred simultaneously with dramatic increases in 100 keV electron fluxes ... Foster, J.; Erickson, P.; Baker, D.; Claudepierre, S.; Kletzing, C.; Kurth, W.; Reeves, G.; Thaller, S.; Spence, H.; Shprits, Y; Wygant, J.; Published by: Geophysical Research Letters Published on: 01/2014 YEAR: 2014 DOI: 10.1002/2013GL058438 |
| 2013 |
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Unusual stable trapping of the ultrarelativistic electrons in the Van Allen radiation belts Radiation in space was the first discovery of the space age. Earth\textquoterights radiation belts consist of energetic particles that are trapped by the geomagnetic field and encircle the planet1. The electron radiation belts usually form a two-zone structure with a stable inner zone and a highly variable outer zone, which forms and disappears owing to wave\textendashparticle interactions on the timescale of a day, and is strongly influenced by the very-low-frequency plasma waves. Recent observations revealed a third radiat ... Shprits, Yuri; Subbotin, Dmitriy; Drozdov, Alexander; Usanova, Maria; Kellerman, Adam; Orlova, Ksenia; Baker, Daniel; Turner, Drew; Kim, Kyung-Chan; Published by: Nature Physics Published on: 11/2013 YEAR: 2013 DOI: 10.1038/nphys2760 |
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In this study we present 3-D data assimilation using CRRES data and 3-D Versatile Electron Radiation Belt Model (VERB) using a newly developed operator-splitting method. Simulations with synthetic data show that the operator-splitting Kalman filtering technique proposed in this study can successfully reconstruct the underlying dynamic evolution of the radiation belts. The method is further verified by the comparison with the conventional Kalman filter. We applied the new approach to 3-D data assimilation of real data to glob ... Shprits, Yuri; Kellerman, Adam; Kondrashov, Dmitri; Subbotin, Dmitriy; Published by: Geophysical Research Letters Published on: 10/2013 YEAR: 2013 DOI: 10.1002/grl.50969 |
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Inner belt energetic protons are a hindrance to development of space technologies. The emission of electromagnetic ion cyclotron (EMIC) waves from spaceborne transmitters has been proposed as a way to solve this problem. The interaction between particles and narrowband emissions has been typically studied using nonlinear test particle simulations. We show that this formulation results in a random walk of the inner belt protons in velocity space. In this paper we compute bounce-averaged pitch angle diffusion rates from test p ... de Soria-Santacruz, M.; Orlova, K.; Martinez-Sanchez, M.; Shprits, Y; Published by: Geophysical Research Letters Published on: 09/2013 YEAR: 2013 DOI: 10.1002/grl.50925 |
| 2012 |
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Explaining sudden losses of outer radiation belt electrons during geomagnetic storms The Van Allen radiation belts were first discovered in 1958 by the Explorer series of spacecraft1. The dynamic outer belt consists primarily of relativistic electrons trapped by the Earth\textquoterights magnetic field. Magnetospheric processes driven by the solar wind2 cause the electron flux in this belt to fluctuate substantially over timescales ranging from minutes to years3. The most dramatic of these events are known as flux \textquoterightdropouts\textquoteright and often occur during geomagnetic storms. During such a ... Turner, Drew; Shprits, Yuri; Hartinger, Michael; Angelopoulos, Vassilis; Published by: Nature Physics Published on: 01/2012 YEAR: 2012 DOI: 10.1038/nphys2185 |
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