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Authors: Sarno-Smith Lois K., Liemohn Michael W., Skoug Ruth M., Santolík Ondrej, Morley Steven K., et al.
Title: Hiss or Equatorial Noise? Ambiguities in Analyzing Suprathermal Ion Plasma Wave Resonance
Abstract: Previous studies have shown that low energy ion heating occurs in the magnetosphere due to strong equatorial noise emission. Observations from the Van Allen Probes Helium Oxygen Proton Electron (HOPE) instrument recently determined there was a depletion in the 1-10 eV ion population in the post-midnight sector of Earth during quiet times at L < 3. The diurnal variation of equatorially mirroring 1-10 eV H+ ions between 2 < L < 3 is connected with similar diurnal variation in the electric field component of plasma waves ranging between 150 and 600 Hz. Measurements from the Van Allen Probes Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) data set are used to analyze waves of this frequency in near-Earth space. However, when we examine the polarization of the wave. . .
Date: 09/2016 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA022975 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA022975/abstract
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Authors: Sarno-Smith Lois K., Liemohn Michael W., Katus Roxanne M., Skoug Ruth M., Larsen Brian A., et al.
Title: Postmidnight depletion of the high-energy tail of the quiet plasmasphere
Abstract: The Van Allen Probes Helium Oxygen Proton Electron (HOPE) instrument measures the high-energy tail of the thermal plasmasphere allowing study of topside ionosphere and inner magnetosphere coupling. We statistically analyze a 22 month period of HOPE data, looking at quiet times with a Kp index of less than 3. We investigate the high-energy range of the plasmasphere, which consists of ions at energies between 1 and 10 eV and contains approximately 5% of total plasmaspheric density. Both the fluxes and partial plasma densities over this energy range show H+ is depleted the most in the postmidnight sector (1–4 magnetic local time), followed by O+ and then He+. The relative depletion of each species across the postmidnight sector is not ordered by mass, which reveals ionospheric influence. We. . .
Date: 03/2015 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2014JA020682 Available at: http://doi.wiley.com/10.1002/2014JA020682
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Authors: Sarno-Smith Lois K., Liemohn Michael W., Skoug Ruth M., Larsen Brian A., Moldwin Mark B., et al.
Title: Local time variations of high-energy plasmaspheric ion pitch angle distributions
Abstract: Recent observations from the Van Allen Probes Helium Oxygen Proton Electron (HOPE) instrument revealed a persistent depletion in the 1–10 eV ion population in the postmidnight sector during quiet times in the 2 < L < 3 region. This study explores the source of this ion depletion by developing an algorithm to classify 26 months of pitch angle distributions measured by the HOPE instrument. We correct the HOPE low energy fluxes for spacecraft potential using measurements from the Electric Field and Waves (EFW) instrument. A high percentage of low count pitch angle distributions is found in the postmidnight sector coupled with a low percentage of ion distributions peaked perpendicular to the field line. A peak in loss cone distributions in the dusk sector is also observed. These results char. . .
Date: 07/2016 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2015JA022301 Available at: http://doi.wiley.com/10.1002/2015JA022301
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Authors: Sarris Theodore E., and Li Xinlin
Title: Calculating ultra-low-frequency wave power of the compressional magnetic field vs. L and time: multi-spacecraft analysis using the Van Allen probes, THEMIS and GOES
Abstract: Ultra-low-frequency (ULF) pulsations are critical in radial diffusion processes of energetic particles, and the power spectral density (PSD) of these fluctuations is an integral part of the radial diffusion coefficients and of assimilative models of the radiation belts. Using simultaneous measurements from two Geostationary Operational Environmental Satellites (GOES) geosynchronous satellites, three satellites of the Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft constellation and the two Van Allen probes during a 10-day period of intense geomagnetic activity and ULF pulsations of October 2012, we calculate the PSDs of ULF pulsations at different L shells. By following the time history of measurements at different L it is shown that, during this tim. . .
Date: 06/2016 Publisher: Annales Geophysicae Pages: 565 - 571 DOI: 10.5194/angeo-34-565-2016 Available at: http://www.ann-geophys.net/34/565/2016/
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Authors: Sarris Theodore E., Li Xinlin, Temerin Michael, Zhao Hong, Califf Sam, et al.
Title: On the Relationship Between Electron Flux Oscillations and ULF Wave-Driven Radial Transport
Abstract: The objective of this study is to investigate the relationship between the levels of electron flux oscillations and radial diffusion for different Phase Space Density (PSD) gradients, through observation and particle tracing simulations under the effect of model Ultra Low Frequency (ULF) fluctuations. This investigation aims to demonstrate that electron flux oscillation is associated with and could be used as an indicator of ongoing radial diffusion. To this direction, flux oscillations are observed through the Van Allen Probes’ MagEIS energetic particle detector; subsequently, flux oscillations are produced in a particle tracing model that simulates radial diffusion by using model magnetic and electric field fluctuations that are approximating measured magnetic and electric field fluctu. . .
Date: 06/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023741 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA023741/full
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Authors: Schiller Q., Kanekal S G, Jian L. K., Li X, Jones A., et al.
Title: Prompt injections of highly relativistic electrons induced by interplanetary shocks: A statistical study of Van Allen Probes observations
Abstract: We conduct a statistical study on the sudden response of outer radiation belt electrons due to interplanetary (IP) shocks during the Van Allen Probes era, i.e., 2012 to 2015. Data from the Relativistic Electron-Proton Telescope instrument on board Van Allen Probes are used to investigate the highly relativistic electron response (E > 1.8 MeV) within the first few minutes after shock impact. We investigate the relationship of IP shock parameters, such as Mach number, with the highly relativistic electron response, including spectral properties and radial location of the shock-induced injection. We find that the driving solar wind structure of the shock does not affect occurrence for enhancement events, 25% of IP shocks are associated with prompt energization, and 14% are associated wi. . .
Date: 12/2016 Publisher: Geophysical Research Letters DOI: 10.1002/2016GL071628 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016GL071628/full
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Authors: Schiller Q., Tu W., Ali A. F., Li X, Godinez H. C., et al.
Title: Simultaneous event-specific estimates of transport, loss, and source rates for relativistic outer radiation belt electrons
Abstract: The most significant unknown regarding relativistic electrons in Earth's outer Van Allen radiation belt is the relative contribution of loss, transport, and acceleration processes within the inner magnetosphere. Detangling each individual process is critical to improve the understanding of radiation belt dynamics, but determining a single component is challenging due to sparse measurements in diverse spatial and temporal regimes. However, there are currently an unprecedented number of spacecraft taking measurements that sample different regions of the inner magnetosphere. With the increasing number of varied observational platforms, system dynamics can begin to be unraveled. In this work, we employ in situ measurements during the 13–14 January 2013 enhancement event to isolate transport,. . .
Date: 03/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023093 Available at: http://doi.wiley.com/10.1002/2016JA023093
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Authors: Schiller Quintin, Li Xinlin, Blum Lauren, Tu Weichao, Turner Drew L, et al.
Title: A nonstorm time enhancement of relativistic electrons in the outer radiation belt
Abstract: Despite the lack of a geomagnetic storm (based on the Dst index), relativistic electron fluxes were enhanced over 2.5 orders of magnitude in the outer radiation belt in 13 h on 13–14 January 2013. The unusual enhancement was observed by Magnetic Electron Ion Spectrometer (MagEIS), onboard the Van Allen Probes; Relativistic Electron and Proton Telescope Integrated Little Experiment, onboard the Colorado Student Space Weather Experiment; and Solid State Telescope, onboard Time History of Events and Macroscale Interactions during Substorms (THEMIS). Analyses of MagEIS phase space density (PSD) profiles show a positive outward radial gradient from 4 < L < 5.5. However, THEMIS observations show a peak in PSD outside of the Van Allen Probes' apogee, which suggest a very interesting s. . .
Date: 01/2014 Publisher: Geophysical Research Letters Pages: 7 - 12 DOI: 10.1002/2013GL058485 Available at: http://doi.wiley.com/10.1002/2013GL058485
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Authors: Schultz Colin
Title: Boom and bust for radiation belt high-energy electron populations
Abstract: Launched on 30 August 2012, the twin Van Allen probes constitute the first dedicated mission in decades to study the Earth's radiation belts. The sensor-laden spacecraft follow a nearly equatorial orbit, which gives them a complete view of the full range of radiation belt processes. In a new study, Baker et al. lay out some of the surprising results unveiled by the crafts' first year in orbit.
Date: 07/2014 Publisher: Eos, Transactions American Geophysical Union Pages: 260 - 260 DOI: 10.1002/eost.v95.2810.1002/2014EO280021 Available at: http://doi.wiley.com/10.1002/2014EO280021
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Authors: Schultz Colin
Title: Dynamics of the Earth's Radiation Belts and Inner Magnetosphere
Abstract: Trapped by Earth's magnetic field far above the planet's surface, the energetic particles that fill the radiation belts are a sign of the Sun's influence and a threat to our technological future. In the AGU monograph Dynamics of the Earth's Radiation Belts and Inner Magnetosphere, editors Danny Summers, Ian R. Mann, Daniel N. Baker, and Michael Schulz explore the inner workings of the magnetosphere. The book reviews current knowledge of the magnetosphere and recent research results and sets the stage for the work currently being done by NASA's Van Allen Probes (formerly known as the Radiation Belt Storm Probes). In this interview, Eos talks to Summers about magnetospheric research, whistler mode waves, solar storms, and the effects of the radiation belts on Earth.
Date: 12/2013 Publisher: Eos, Transactions American Geophysical Union Pages: 509 - 509 DOI: 10.1002/eost.v94.5210.1002/2013EO520007 Available at: http://doi.wiley.com/10.1002/eost.v94.52http://doi.wiley.com/10.1002/2013EO520007
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Authors: Selesnick R. S., Baker D N, Kanekal S G, Hoxie V C, and Li X
Title: Modeling the Proton Radiation Belt With Van Allen Probes Relativistic Electron-Proton Telescope Data
Abstract: An empirical model of the proton radiation belt is constructed from data taken during 2013–2017 by the Relativistic Electron-Proton Telescopes on the Van Allen Probes satellites. The model intensity is a function of time, kinetic energy in the range 18–600 MeV, equatorial pitch angle, and L shell of proton guiding centers. Data are selected, on the basis of energy deposits in each of the nine silicon detectors, to reduce background caused by hard proton energy spectra at low L. Instrument response functions are computed by Monte Carlo integration, using simulated proton paths through a simplified structural model, to account for energy loss in shielding material for protons outside the nominal field of view. Overlap of energy channels, their wide angular response, and changing satellit. . .
Date: 01/2018 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024661 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA024661/full
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Authors: Selesnick R. S., Baker D N, Jaynes A. N., Li X, Kanekal S G, et al.
Title: Inward diffusion and loss of radiation belt protons
Abstract: Radiation belt protons in the kinetic energy range 24 to 76 MeV are being measured by the Relativistic Electron Proton Telescope on each of the two Van Allen Probes. Data have been processed for the purpose of studying variability in the trapped proton intensity during October 2013 to August 2015. For the lower energies (≲32 MeV), equatorial proton intensity near L = 2 showed a steady increase that is consistent with inward diffusion of trapped solar protons, as shown by positive radial gradients in phase space density at fixed values of the first two adiabatic invariants. It is postulated that these protons were trapped with enhanced efficiency during the 7 March 2012 solar proton event. A model that includes radial diffusion, along with known trapped proton source and loss processes, s. . .
Date: 03/2016 Publisher: Journal of Geophysical Research: Space Physics Pages: n/a - n/a DOI: 10.1002/2015JA022154 Available at: http://onlinelibrary.wiley.com/wol1/doi/10.1002/2015JA022154/full
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Authors: Selesnick R. S., and Albert J M
Title: Variability of the Proton Radiation Belt
Abstract: Significant steady but slow variability of radiation belt proton intensity, in the energy range ∼19–200 MeV and for L<2.4, has been observed in an empirical model derived from data taken by Van Allen Probes during 2013–2019. It is compared to predictions of a theoretical model based on measured initial and boundary conditions. Two aspects of the variability are considered in detail and require adjustments to model parameters. Observed inward transport of proton intensity maxima near L=1.9 and associated increasing intensity are caused in the model by inward radial diffusion from an external source while conserving the first two adiabatic invariants. The diffusion coefficient is constrained by these observations and is required to have increased near the start of 2015 by a factor ∼2. . .
Date: 07/2019 Publisher: Journal of Geophysical Research: Space Physics Pages: 5516 - 5527 DOI: 10.1029/2019JA026754 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019JA026754
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Authors: Selesnick R. S., Baker D N, Jaynes A. N., Li X, Kanekal S G, et al.
Title: Observations of the inner radiation belt: CRAND and trapped solar protons
Abstract: Measurements of inner radiation belt protons have been made by the Van Allen Probes Relativistic Electron-Proton Telescopes as a function of kinetic energy (24 to 76 MeV), equatorial pitch angle, and magnetic L shell, during late-2013 and early-2014. A probabilistic data analysis method reduces background from contamination by higher energy protons. Resulting proton intensities are compared to predictions of a theoretical radiation belt model. Then trapped protons originating both from cosmic ray albedo neutron decay (CRAND) and from trapping of solar protons are evident in the measured distributions. An observed double-peaked distribution in L is attributed, based on the model comparison, to a gap in the occurrence of solar proton events during the 2007 to 2011 solar minimum. Equatorial. . .
Date: 08/2014 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2014JA020188 Available at: http://doi.wiley.com/10.1002/2014JA020188
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Authors: Selesnick R. S., Su Y.-J., and Blake J B
Title: Control of the innermost electron radiation belt by large-scale electric fields
Abstract: Electron measurements from the Magnetic Electron Ion Spectrometer instruments on Van Allen Probes, for kinetic energies ∼100 to 400 keV, show characteristic dynamical features of the innermost ( inline image) radiation belt: rapid injections, slow decay, and structured energy spectra. There are also periods of steady or slowly increasing intensity and of fast decay following injections. Local time asymmetry, with higher intensity near dawn, is interpreted as evidence for drift shell distortion by a convection electric field of magnitude ∼0.4 mV/m during geomagnetically quiet times. Fast fluctuations in the electric field, on the drift time scale, cause inward diffusion. Assuming that they are proportional to changes in Kp, the resulting diffusion coefficient is sufficient to replenish . . .
Date: 08/2016 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA022973 Available at: http://doi.wiley.com/10.1002/2016JA022973
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Authors: Shankar Uday J, McGee Timothy G, and Kemp Brian L
Title: Analysis of Spinning Spacecraft with Wire Booms Part 3: Spin-Plane Dynamics, Maneuvers, and Deployment
Abstract: Several science spacecraft use long wire booms as electric-field antennas and the spacecraft spins to maintain the orientation of these flexible wires. These booms account for a majority of the total spacecraft inertia while weighing only a small fraction of the total mass. The spacecraft dynamics is therefore dominated by these booms. The analysis of such spacecraft is further complicated by other flexible ap- pendages and the presence of damping in the system, both inherent in the sys- tem and from damping mechanisms deliberately added into the system. This pa- per and two companion papers analyze such spacecraft. The first of these derives the governing nonlinear equations from first principles. Under certain conditions, the dynamics neatly separate into spin-plane and out-of-p. . .
Date: 08/2009 Publisher: AIAA Guidance, Navigation, and Control Conference DOI: 10.2514/6.2009-6204 Available at: http://arc.aiaa.org/doi/pdf/10.2514/6.2009-6204
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Authors: Shekhar Sapna, Millan Robyn, and Smith David
Title: A Statistical Study of the Spatial Extent of Relativistic Electron Precipitation with Polar Orbiting Environmental Satellites.
Abstract: Relativistic Electron Precipitation (REP) in the atmosphere can contribute significantly to electron loss from the outer radiation belts. In order to estimate the contribution to this loss, it is important to estimate the spatial extent of the precipitation region. We observed REP with the zenith pointing (0o) Medium Energy Proton Electron Detector (MEPED) on board Polar Orbiting Environmental Satellites (POES), for 15 years (2000-2014) and used both single and multi satellite measurements to estimate an average extent of the region of precipitation in L shell and Magnetic Local Time (MLT). In the duration of 15 years (2000-2014), 31035 REP events were found in this study. Events were found to split into two classes; one class of events coincided with proton precipitation in the P1 channel. . .
Date: 10/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024716 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA024716/full
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Authors: Shen Xiao-Chen, Hudson Mary, Jaynes Allison, Shi Quanqi, Tian Anmin, et al.
Title: Statistical study of the storm-time radiation belt evolution during Van Allen Probes era: CME- versus CIR-driven storms
Abstract: CME- or CIR-driven storms can change the electron distributions in the radiation belt dramatically, which can in turn affect the spacecraft in this region or induce geomagnetic effects. The Van Allen Probes twin spacecraft, launched on 30 August 2012, orbit near the equatorial plane and across a wide range of L∗ with apogee at 5.8 RE and perigee at 620 km. Electron data from Van Allen Probes MagEIS and REPT instruments have been binned every six hours at L∗=3 (defined as 2.5 Date: 07/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024100 Available at: onlinelibrary.wiley.com/doi/10.1002/2017JA024100/full
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Authors: Shen Xiao‐Chen, Li Wen, Ma Qianli, Agapitov Oleksiy, and Nishimura Yukitoshi
Title: Statistical Analysis of Transverse Size of Lower Band Chorus Waves Using Simultaneous Multisatellite Observations
Abstract: Chorus waves are known to accelerate or scatter energetic electrons via quasi‐linear or nonlinear wave‐particle interactions in the Earth's magnetosphere. In this letter, by taking advantage of simultaneous observations of chorus waveforms from at least a pair of probes among Van Allen Probes and/or Time History of Events and Macroscale Interactions during Substorms (THEMIS) missions, we statistically calculate the transverse size of lower band chorus wave elements. The average size of lower band chorus wave element is found to be ~315±32 km over L shells of ~5–6. Furthermore, our results suggest that the scale size of lower band chorus tends to be (1) larger at higher L shells; (2) larger at higher magnetic latitudes, especially on the dayside; and (3) larger in the azimuthal direc. . .
Date: 05/2019 Publisher: Geophysical Research Letters DOI: 10.1029/2019GL083118 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019GL083118
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Authors: Shi Run, Li Wen, Ma Qianli, Green Alex, Kletzing Craig A., et al.
Title: Properties of Whistler Mode Waves in Earth's Plasmasphere and Plumes
Abstract: Whistler mode wave properties inside the plasmasphere and plumes are systematically investigated using 5‐year data from Van Allen Probes. The occurrence and intensity of whistler mode waves in the plasmasphere and plumes exhibit dependences on magnetic local time, L, and AE. Based on the dependence of the wave normal angle and Poynting flux direction on L shell and normalized wave frequency to electron cyclotron frequency (fce), whistler mode waves are categorized into four types. Type I: ~0.5 fce with oblique wave normal angles mostly in plumes; Type II: 0.01–0.5 fce with small wave normal angles in the outer plasmasphere or inside plumes; Type III: <0.01 fce with oblique wave normal angles mostly within the plasmasphere or plumes; Type IV: 0.05–0.5 fce with oblique wave normal angl. . .
Date: 01/2019 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2018JA026041 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JA026041
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Authors: Shi R., Mourenas D., Artemyev A., Li W, and Ma Q
Title: Highly Oblique Lower-Band Chorus Statistics: Dependencies of Wave Power on Refractive Index and Geomagnetic Activity
Abstract: We use 3 years of Van Allen Probes observations of highly oblique lower‐band chorus waves at low latitudes over L = 4–6 to provide a comprehensive statistics of the distribution of their magnetic and electric powers and full energy density as a function of wave refractive index N, L shell, and geomagnetic activity AE. We use the refractive index calculated either in the cold plasma approximation or in the quasi‐electrostatic (hot plasma) approximation and either observed wave electric fields or corrected wave electric fields accounting for the formation of a plasma sheath around antenna probes in a low‐density plasma. Approximate fits to the maximum refractive index and to the magnetic wave power profile of highly oblique waves are provided as a function of AE and L. Such fits shou. . .
Date: 06/2018 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2018JA025337 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JA025337
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Authors: Shi Run, Summers Danny, Ni Binbin, Fennell Joseph F., Blake Bernard, et al.
Title: Survey of radiation belt energetic electron pitch angle distributions based on the Van Allen Probes MagEIS measurements
Abstract: A statistical survey of electron pitch angle distributions (PADs) is performed based on the pitch angle resolved flux observations from the Magnetic Electron Ion Spectrometer (MagEIS) instrument on board the Van Allen Probes during the period from 1 October 2012 to 1 May 2015. By fitting the measured PADs to a sinnα form, where α is the local pitch angle and n is the power law index, we investigate the dependence of PADs on electron kinetic energy, magnetic local time (MLT), the geomagnetic Kp index and L-shell. The difference in electron PADs between the inner and outer belt is distinct. In the outer belt, the common averaged n values are less than 1.5, except for large values of the Kp index and high electron energies. The averaged n values vary considerably with MLT, with a peak in th. . .
Date: 12/2015 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2015JA021724 Available at: http://doi.wiley.com/10.1002/2015JA021724http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2F2015JA021724
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Authors: Shi Run, Summers Danny, Ni Binbin, Manweiler Jerry W., Mitchell Donald G., et al.
Title: A statistical study of proton pitch angle distributions measured by the Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE)
Abstract: A statistical study of ring current-energy proton pitch angle distributions (PADs) in Earth's inner magnetosphere is reported here. The data are from the Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) on board the Van Allen Probe B spacecraft from January 1, 2013 to April 15, 2015. By fitting the data to the functional form sinnα, where α is the proton pitch angle, we examine proton PADs at the energies 50, 100, 180, 328 and 488 keV in the L-shell range from L = 2.5 to L = 6. Three PAD types are classified: trapped (90° peaked), butterfly and isotropic. The proton PAD dependence on the particle energy, MLT, L-shell, and geomagnetic activity are analyzed in detail. The results show a strong dependence of the proton PADs on MLT. On the nightside, the n values o. . .
Date: 05/2016 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2015JA022140 Available at: http://doi.wiley.com/10.1002/2015JA022140
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Authors: Shprits Yuri Y, Horne Richard B, Kellerman Adam C., and Drozdov Alexander Y.
Title: The dynamics of Van Allen belts revisited
Abstract: N/A
Date: 02/2019 Publisher: Nature Physics Pages: 102 - 103 DOI: 10.1038/nphys4350 Available at: https://www.nature.com/articles/nphys4350
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Authors: Shprits Yuri Y, Subbotin Dmitriy, Drozdov Alexander, Usanova Maria E., Kellerman Adam, et al.
Title: Unusual stable trapping of the ultrarelativistic electrons in the Van Allen radiation belts
Abstract: Radiation in space was the first discovery of the space age. Earth’s 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–particle interactions on the timescale of a day, and is strongly influenced by the very-low-frequency plasma waves. Recent observations revealed a third radiation zone at ultrarelativistic energies2, with the additional medium narrow belt (long-lived ring) persisting for approximately 4 weeks. This new ring resulted from a combination of electron losses to the interplanetary medium and scattering by electromagnetic ion cyclotron waves to the Ear. . .
Date: 11/2013 Publisher: Nature Physics Pages: 699 - 703 DOI: 10.1038/nphys2760 Available at: http://www.nature.com/doifinder/10.1038/nphys2760
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Authors: Shprits Yuri Y, Kellerman Adam, Drozdov Alexander, Spense Harlan, Reeves Geoffrey, et al.
Title: Combined Convective and Diffusive Simulations: VERB-4D Comparison with March 17, 2013 Van Allen Probes Observations
Abstract: 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 the scale of ~100MeV/G may resemble ring current or relativistic electron trajectories depending on the level of geomagnetic activity. Simulations with the VERB-4D code including convection, radial diffusion, and energy diffusion are presented. Sensitivity simulations in. . .
Date: 09/2015 Publisher: Geophysical Research Letters DOI: 10.1002/2015GL065230 Available at: http://doi.wiley.com/10.1002/2015GL065230
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Authors: Shumko Mykhaylo, Turner Drew L, O'Brien T P, Claudepierre Seth G., Sample John, et al.
Title: Evidence of Microbursts Observed Near the Equatorial Plane in the Outer Van Allen Radiation Belt
Abstract: We present the first evidence of electron microbursts observed near the equatorial plane in Earth's outer radiation belt. We observed the microbursts on March 31st, 2017 with the Magnetic Electron Ion Spectrometer and RBSP Ion Composition Experiment on the Van Allen Probes. Microburst electrons with kinetic energies of 29‐92 keV were scattered over a substantial range of pitch angles, and over time intervals of 150‐500 ms. Furthermore, the microbursts arrived without dispersion in energy, indicating that they were recently scattered near the spacecraft. We have applied the relativistic theory of wave‐particle resonant diffusion to the calculated phase space density, revealing that the observed transport of microburst electrons is not consistent with the hypothesized quasi‐linear ap. . .
Date: 07/2018 Publisher: Geophysical Research Letters DOI: 10.1029/2018GL078451 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL078451
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Authors: Sigsbee K., Kletzing C A, Smith C W, MacDowall Robert, Spence Harlan, et al.
Title: Van Allen Probes, THEMIS, GOES, and Cluster Observations of EMIC waves, ULF pulsations, and an electron flux dropout
Abstract: We examined an electron flux dropout during the 12–14 November 2012 geomagnetic storm using observations from seven spacecraft: the two Van Allen Probes, THEMIS-A (P5), Cluster 2, and Geostationary Operational Environmental Satellite (GOES) 13, 14, and 15. The electron fluxes for energies greater than 2.0 MeV observed by GOES 13, 14, and 15 at geosynchronous orbit and by the Van Allen Probes remained at or near instrumental background levels for more than 24 hours from 12–14 November. For energies of 0.8 MeV, the GOES satellites observed two shorter intervals of reduced electron fluxes. The first interval of reduced 0.8 MeV electron fluxes on 12–13 November was associated with an interplanetary shock and a sudden impulse. Cluster, THEMIS, and GOES observed intense He+ EMIC wa. . .
Date: 01/2016 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2014JA020877 Available at: http://doi.wiley.com/10.1002/2014JA020877
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Authors: Skov Tamitha Mulligan, Fennell Joseph F., Roeder James L., Blake Bernard, and Claudepierre Seth G.
Title: Internal Charging Hazards in Near-Earth Space During Solar Cycle 24 Maximum: Van Allen Probes Measurements
Abstract: The Van Allen Probes mission provides an unprecedented opportunity to make detailed measurements of electrons and protons in the inner magnetosphere during the weak solar maximum period of cycle 24. The MagEIS suite of sensors measures energy spectra and fluxes of charged particles in the space environment. The calculations show that these fluxes result in electron deposition rates high enough to cause internal charging. We use omnidirectional fluxes of electrons and protons to calculate the dose under varying materials and thicknesses of shielding. We show examples of charge deposition rates during the times of nominal and high levels of penetrating fluxes in the inner magnetosphere covering the period from the beginning of 2013 through mid-2014. These charge deposition rates are related . . .
Date: 09/2015 Publisher: IEEE Transactions on Plasma Science Pages: 3070 - 3074 DOI: 10.1109/TPS.2015.2468214 Available at: http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=7247811http://xplorestaging.ieee.org/ielx7/27/7247791/07247811.pdf?arnumber=7247811
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Authors: Skov Mulligan, Fennell J.F., Roeder J.L., Blake J.B., and Claudepierre S.G.
Title: Internal Charging Hazards in Near-Earth Space during Solar Cycle 24 Maximum: Van Allen Probes Measurements
Abstract: The Van Allen Probes mission provides an unprecedented opportunity to make detailed measurements of electrons and protons in the inner magnetosphere during the weak solar maximum period of cycle 24. Data from the MagEIS suite of sensors measures energy spectra, fluxes, and yields electron deposition rates that can cause internal charging. We use omni-directional fluxes of electrons and protons to calculate the dose under varying materials and thicknesses of shielding (similar to Fennell et al., 2010). We show examples of charge deposition rates during times of nominal and high levels of penetrating fluxes in the inner magnetosphere covering the period from late 2012 through 2013. These charge deposition rates are related to charging levels quite possibly encountered. . .
Date: 09/2015 Publisher: JPL DOI: 10.1109/TPS.2015.2468214 Available at: http://ieeexplore.ieee.org/document/7247811/?reload=true&arnumber=7247811
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Authors: Smirnov A. G., Kronberg E. A., Latallerie F., Daly P. W., Aseev N. A., et al.
Title: Electron intensity measurements by the Cluster/RAPID/IES instrument in Earth's radiation belts and ring current
Abstract: The Cluster mission, launched in 2000, has produced a large database of electron flux intensity measurements in the Earth's 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 algorithms for background correction. The first algorithm is based on the empirical contamination percentages by both protons and electrons. The second algorithm uses simultaneous proton observations. The efficiencies of these algorithms are demonstrated by comparison of the . . .
Date: 02/2019 Publisher: Space Weather DOI: 10.1029/2018SW001989 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018SW001989
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Authors: Smith Evan J., Butler Michael H., Fretz Kristin, and Wilhelm Benjamin
Title: Lithium Ion Battery Fault Management on the Van Allen Probes
Abstract: The Van Allen Probes (formerly known as the Radiation Belt Storm Probes or RBSP) mission launched on 30 August 2012 as part of NASA’s Living With a Star (LWS) Program. The ultimate goal of the mission is to understand how populations of relativistic electrons and penetrating ions in the Earth’s Van Allen Radiation Belts are affected by the Sun. The mission consists of two nearly identical observatories orbiting in highly-elliptical Earth orbits. The two satellite system allows for the study of the spatial and temporal effects the Sun has on the Earth’s radiation belts. Each observatory is equipped with a suite of instruments designed to continuously study ions, electrons and the local magnetic and electric fields. A brief overview of the Van Allen Probe mission is pre. . .
Date: 09/2013 Publisher: American Institute of Aeronautics and Astronautics DOI: 10.2514/6.2013-5526 Available at: http://arc.aiaa.org/doi/pdf/10.2514/6.2013-5526
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Authors: Sorathia K. A., Ukhorskiy A Y, Merkin V. G., Fennell J. F., and Claudepierre S G
Title: Modeling the Depletion and Recovery of the Outer Radiation Belt During a Geomagnetic Storm: Combined MHD and Test Particle Simulations
Abstract: During geomagnetic storms the intensities of the outer radiation belt electron population can exhibit dramatic variability. Deep depletions in intensity during the main phase are followed by increases during the recovery phase, often to levels that significantly exceed their pre‐storm values. To study these processes, we simulate the evolution of the outer radiation belt during the 17 March 2013 geomagnetic storm using our newly‐developed radiation belt model (CHIMP) based on test particle and coupled 3D ring current and global MHD simulations, and driven solely with solar wind and F10.7 flux data. Our approach differs from previous work in that we use MHD information to identify regions of strong, bursty, and azimuthally localized Earthward convection in the magnetotail where test. . .
Date: 06/2018 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2018JA025506 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JA025506
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Authors: Soto-Chavez A. R., Lanzerotti L J, Manweiler J W, Gerrard A., Cohen R., et al.
Title: Observational evidence of the drift-mirror plasma instability in Earth's inner magnetosphere
Abstract: We report on evidence for the generation of an ultra-low frequency plasma wave by the drift-mirror plasma instability in the dynamic plasma environment of Earth's inner magnetosphere. The plasma measurements are obtained from the Radiation Belt Storm Probes Ion Composition Experiment onboard NASA's Van Allen Probes Satellites. We show that the measured wave-particle interactions are driven by the drift-mirror instability. Theoretical analysis of the data demonstrates that the drift-mirror mode plasma instability condition is well satisfied. We also demonstrate, for the first time, that the measured wave growth rate agrees well with the predicted linear theory growth rate. Hence, the in-situ space plasma observations and theoretical analysis demonstrate that local generation of ultra-low fr. . .
Date: 04/2019 Publisher: Physics of Plasmas Pages: 042110 DOI: 10.1063/1.5083629 Available at: https://doi.org/10.1063/1.5083629
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Authors: Soto-Chavez A. R., Lanzerotti L J, Gerrard A., Kim H., Bortnik J, et al.
Title: RBSPICE measurement of ion loss during the 2015 March storm: Adiabatic response to the geomagnetic field change
Abstract: A strongly energy-dependent ring current ion loss was measured by the RBSPICE instrument on the Van Allen Probes A spacecraft in the local evening sector during the 17 March 2015 geomagnetic storm. The ion loss is found to be energy dependent where only ions with energies measured above ∼ 150 keV have a significant drop in intensity. At these energies the ion dynamics are principally controlled by variations of the geomagnetic field which, during magnetic storms, exhibits large scale variations on timescales from minutes to hours. Here we show that starting from ∼ 19:10 UTC on March 17 the geomagnetic field increased from 220 to 260 nT on a time scale of about an hour as captured by RBSPICE-A close to spacecraft apogee, L = 6.1 and MLT = 21.85 hr. [GSM coordinates X=-4.89, Y=3.00, . . .
Date: 09/2016 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA022512 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA022512/abstract
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Authors: Souza V. M., Lopez R. E., Jauer P. R., Sibeck D G, Pham K., et al.
Title: Acceleration of radiation belt electrons and the role of the average interplanetary magnetic field B z component in high speed streams
Abstract: In this study we examine the recovery of relativistic radiation belt electrons on November 15-16, 2014, after a previous reduction in the electron flux resulting from the passage of a Corotating Interaction Region (CIR). Following the CIR, there was a period of high-speed streams characterized by large, nonlinear fluctuations in the interplanetary magnetic field (IMF) components. However, the outer radiation belt electron flux remained at a low level for several days before it increased in two major steps. The first increase is associated with the IMF background field turning from slightly northward on average, to slightly southward on average. The second major increase is associated with an increase in the solar wind velocity during a period of southward average IMF background field. We p. . .
Date: 08/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024187 Available at: onlinelibrary.wiley.com/doi/10.1002/2017JA024187/full
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Authors: Souza V. M., Vieira L. E. A., Medeiros C., Da Silva L. A., Alves L. R., et al.
Title: A neural network approach for identifying particle pitch angle distributions in Van Allen Probes data
Abstract: Analysis of particle pitch angle distributions (PADs) has been used as a means to comprehend a multitude of different physical mechanisms that lead to flux variations in the Van Allen belts and also to particle precipitation into the upper atmosphere. In this work we developed a neural network-based data clustering methodology that automatically identifies distinct PAD types in an unsupervised way using particle flux data. One can promptly identify and locate three well-known PAD types in both time and radial distance, namely, 90° peaked, butterfly, and flattop distributions. In order to illustrate the applicability of our methodology, we used relativistic electron flux data from the whole month of November 2014, acquired from the Relativistic Electron-Proton Telescope instrument on board. . .
Date: 04/2016 Publisher: Space Weather Pages: n/a - n/a DOI: 10.1002/2015SW001349 Available at: http://doi.wiley.com/10.1002/2015SW001349http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2F2015SW001349
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Authors: Spasojevic M., Shprits Y.Y., and Orlova K.
Title: Global Empirical Models of Plasmaspheric Hiss using Van Allen Probes
Abstract: Plasmaspheric hiss is a whistler mode emission that permeates the Earth's 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 Allen Probes data. First, we describe the construction of the hiss database. Then, we compare the hiss spectral distribution and integrated wave amplitude obtained from Van Allen Probes to those previously extracted from the CRRES mission. Next, we develop a cubic regression model o. . .
Date: 11/2015 Publisher: Journal of Geophysical Research: Space Physics Pages: n/a - n/a DOI: 10.1002/2015JA021803 Available at: http://doi.wiley.com/10.1002/2015JA021803http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2F2015JA021803
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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: Spence H E, Reeves G D, Baker D N, Blake J B, Bolton M, et al.
Title: Science Goals and Overview of the Energetic Particle, Composition, and Thermal Plasma (ECT) Suite on NASA’s Radiation Belt Storm Probes (RBSP) Mission
Abstract: The Radiation Belt Storm Probes (RBSP)-Energetic Particle, Composition, and Thermal Plasma (ECT) suite contains an innovative complement of particle instruments to ensure the highest quality measurements ever made in the inner magnetosphere and radiation belts. The coordinated RBSP-ECT particle measurements, analyzed in combination with fields and waves observations and state-of-the-art theory and modeling, are necessary for understanding the acceleration, global distribution, and variability of radiation belt electrons and ions, key science objectives of NASA’s Living With a Star program and the Van Allen Probes mission. The RBSP-ECT suite consists of three highly-coordinated instruments: the Magnetic Electron Ion Spectrometer (MagEIS), the Helium Oxygen Proton Electron (HOPE) senso. . .
Date: 11/2013 Publisher: Space Science Reviews Pages: 311-336 DOI: DOI: 10.1007/s11214-013-0007-5 Available at: http://link.springer.com/article/10.1007%2Fs11214-013-0007-5
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Authors: Srinivasan Dipak K., Adams Norm, and Wallis Robert
Title: In-flight performance of the Van Allen Probes RF telecommunications system
Abstract: The NASA Van Allen Probes mission (previously called the Radiation Belt Storm Probes) successfully launched on 30 August 2012. The twin spacecraft, designed, built, and operated by The Johns Hopkins University Applied Physics Laboratory (JHU/APL), has been successfully operating within Earth׳s radiation belts since then, returning critical science data revealing new insights into the physics of the radiation belts. Because of the extreme radiation environment, all spacecraft subsystems including the communications system had to make special accommodations to withstand the effects of the radiation. Each Van Allen Probes spacecraft׳s telecommunications system includes an S-band version of the Frontier Radio, a solid-state power amplifier, RF routing components, and dual low-gain antenna. . .
Date: 11/2015 Publisher: Acta Astronautica Pages: 211 - 221 DOI: 10.1016/j.actaastro.2015.05.001 Available at: http://www.sciencedirect.com/science/article/pii/S0094576515001824
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Authors: Stepanova M., Antonova E.E., Moya P.S., Pinto V.A., and Valdivia J.A.
Title: Multisatellite Analysis of Plasma Pressure in the Inner Magnetosphere During the 1 June 2013 Geomagnetic Storm
Abstract: Using data from Defense Meteorological Satellite Program 16–18, National Oceanic and Atmospheric Administration 15–19, and METOP 1–2 satellites, we reconstructed for the first time a two‐dimensional statistical distribution of plasma pressure in the inner magnetosphere during the 1 June 2013 geomagnetic storm with time resolution of 6 hr. Simultaneously, we used the data from Van Allen Probes and Time History of Events and Macroscale Interactions missions to obtain the in situ plasma pressure in the equatorial plane. This allowed us to corroborate that the dipole mapping works reasonably well during the storm time and that variations of plasma pressure are consistent at low and high altitudes; namely, we observed a drastic increase in plasma pressure a few hours before the storm on. . .
Date: 01/2019 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2018JA025965 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JA025965
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Authors: Stephens G. K., Sitnov M I, Korth H., Tsyganenko N A, Ohtani S, et al.
Title: Global Empirical Picture of Magnetospheric Substorms Inferred From Multimission Magnetometer Data
Abstract: Magnetospheric substorms represent key explosive processes in the interaction of the Earth's magnetosphere with the solar wind, and their understanding and modeling are critical for space weather forecasting. During substorms, the magnetic field on the nightside is first stretched in the antisunward direction and then it rapidly contracts earthward bringing hot plasmas from the distant space regions into the inner magnetosphere, where they contribute to geomagnetic storms and Joule dissipation in the polar ionosphere, causing impressive splashes of aurora. Here we show for the first time that mining millions of spaceborne magnetometer data records from multiple missions allows one to reconstruct the global 3‐D picture of these stretching and dipolarization processes. Stretching results i. . .
Date: 01/2019 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2018JA025843 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JA025843
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Authors: Stephens G. K., Sitnov M I, Ukhorskiy A Y, Roelof E. C., Tsyganenko N A, et al.
Title: Empirical modeling of the storm-time innermost magnetosphere using Van Allen Probes and THEMIS data: Eastward and banana currents
Abstract: The structure of storm-time currents in the inner magnetosphere, including its innermost region inside 4RE, is studied for the first time using a modification of the empirical geomagnetic field model TS07D and new data from Van Allen Probes and THEMIS missions. It is shown that the model, which uses basis-function expansions instead of ad hoc current modules to approximate the magnetic field, consistently improves its resolution and magnetic field reconstruction with the increase of the number of basis functions and resolves the spatial structure and evolution of the innermost eastward current. This includes a connection between the westward ring current flowing largely at inline image and the eastward ring current concentrated at inline image resulting in a vortex current pattern. A simil. . .
Date: 01/2015 Publisher: Journal of Geophysical Research: Space Physics Pages: n/a - n/a DOI: 10.1002/2015JA021700 Available at: http://doi.wiley.com/10.1002/2015JA021700
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Authors: Stratton J M, Harvey R J, and Heyler G A
Title: Mission Overview for the Radiation Belt Storm Probes Mission
Abstract: Provided here is an overview of Radiation Belt Storm Probes (RBSP) mission design. The driving mission and science requirements are presented, and the unique engineering challenges of operating in Earth’s radiation belts are discussed in detail. The implementation of both the space and ground segments are presented, including a discussion of the challenges inherent with operating multiple observatories concurrently and working with a distributed network of science operation centers. An overview of the launch vehicle and the overall mission design will be presented, and the plan for space weather data broadcast will be introduced.
Date: 01/2013 Publisher: Space Science Reviews DOI: 10.1007/s11214-012-9933-x Available at: http://link.springer.com/article/10.1007%2Fs11214-012-9933-x
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Authors: Su Zhenpeng, Xiao Fuliang, Zheng Huinan, and Zhu Hui
Title: Chorus-driven acceleration of radiation belt electrons in the unusual temporal/spatial regions
Abstract: Cyclotron resonance with whistler-mode chorus waves is an important mechanism for the local acceleration of radiation belt energetic electrons. Such acceleration process has been widely investigated during the storm times, and its favored region is usually considered to be the low-density plasmatrough with magnetic local time (MLT) from midnight through dawn to noon. Here we present two case studies on the chorus-driven acceleration of radiation belt electrons in some “unusual” temporal /spatial regions. (1) The first event recorded by the Van Allen Probes during the nonstorm times from 21 to 23 February 2013. Within two days, a new radiation belt centering around L=5.8 formed and gradually merged with the original outer belt. The corresponding relativistic electron fluxes increased by. . .
Date: 08/2014 Publisher: IEEE DOI: 10.1109/URSIGASS.2014.6929875 Available at: http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6929875
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Authors: Su Zhenpeng, Zhu Hui, Xiao Fuliang, Zheng Huinan, Wang Yuming, et al.
Title: Intense duskside lower band chorus waves observed by Van Allen Probes: Generation and potential acceleration effect on radiation belt electrons
Abstract: Local acceleration driven by whistler mode chorus waves largely accounts for the enhancement of radiation belt relativistic electron fluxes, whose favored region is usually considered to be the plasmatrough with magnetic local time approximately from midnight through dawn to noon. On 2 October 2013, the Van Allen Probes recorded a rarely reported event of intense duskside lower band chorus waves (with power spectral density up to 10−3nT2/Hz) in the low-latitude region outside of L=5. Such chorus waves are found to be generated by the substorm-injected anisotropic suprathermal electrons and have a potentially strong acceleration effect on the radiation belt energetic electrons. This event study demonstrates the possibility of broader spatial regions with effective electron acceleration by. . .
Date: 06/2014 Publisher: Journal of Geophysical Research: Space Physics Pages: 4266 - 4273 DOI: 10.1002/jgra.v119.610.1002/2014JA019919 Available at: http://doi.wiley.com/10.1002/jgra.v119.6http://doi.wiley.com/10.1002/2014JA019919
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Authors: Su Zhenpeng, Liu Nigang, Zheng Huinan, Wang Yuming, and Wang Shui
Title: Large-Amplitude Extremely Low Frequency Hiss Waves in Plasmaspheric Plumes
Abstract: N/A
Date: 01/2018 Publisher: Geophysical Research Letters DOI: 10.1002/2017GL076754 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017GL076754/full
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Authors: Su Zhenpeng, Wang Geng, Liu Nigang, Zheng Huinan, Wang Yuming, et al.
Title: Direct observation of generation and propagation of magnetosonic waves following substorm injection
Abstract: Magnetosonic whistler mode waves play an important role in the radiation belt electron dynamics. Previous theory has suggested that these waves are excited by the ring distributions of hot protons and can propagate radially and azimuthally over a broad spatial range. However, because of the challenging requirements on satellite locations and data-processing techniques, this theory was difficult to validate directly. Here we present some experimental tests of the theory on the basis of Van Allen Probes observations of magnetosonic waves following substorm injections. At higher L-shells with significant substorm injections, the discrete magnetosonic emission lines started approximately at the proton gyrofrequency harmonics, qualitatively consistent with the prediction of linear proton Bernst. . .
Date: 07/2018 Publisher: Geophysical Research Letters DOI: 10.1002/2017GL074362 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017GL074362/full
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Authors: Su Zhenpeng, Zhu Hui, Xiao Fuliang, Zong Q.-G., Zhou X.-Z., et al.
Title: Ultra-low-frequency wave-driven diffusion of radiation belt relativistic electrons
Abstract: Van Allen radiation belts are typically two zones of energetic particles encircling the Earth separated by the slot region. How the outer radiation belt electrons are accelerated to relativistic energies remains an unanswered question. Recent studies have presented compelling evidence for the local acceleration by very-low-frequency (VLF) chorus waves. However, there has been a competing theory to the local acceleration, radial diffusion by ultra-low-frequency (ULF) waves, whose importance has not yet been determined definitively. Here we report a unique radiation belt event with intense ULF waves but no detectable VLF chorus waves. Our results demonstrate that the ULF waves moved the inner edge of the outer radiation belt earthward 0.3 Earth radii and enhanced the relativistic electron fl. . .
Date: 12/2015 Publisher: Nature Communications Pages: 10096 DOI: 10.1038/ncomms10096 Available at: http://www.nature.com/doifinder/10.1038/ncomms10096
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