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Journal Article
Authors: Ni Binbin, Bortnik Jacob, Thorne Richard M, Ma Qianli, and Chen Lunjin
Title: Resonant scattering and resultant pitch angle evolution of relativistic electrons by plasmaspheric hiss
Abstract: We perform a comprehensive analysis to evaluate hiss-induced scattering effect on the pitch angle evolution and associated decay processes of relativistic electrons. The results show that scattering by the equatorial, highly oblique hiss component is negligible. Quasi-parallel approximation is good for evaluation of hiss-driven electron scattering rates ≤ 2 MeV. However, realistic wave propagation angles as a function of latitude must be considered to accurately quantify hiss scattering rates above 2 MeV, and ambient plasma density is also a critical parameter. While the first-order cyclotron and the Landau resonances are dominant for hiss scattering < 2 MeV electrons, higher-order resonances become important and even dominant at intermediate pitch angles for ultrarelativistic (≥. . .
Date: 12/2013 Publisher: Journal of Geophysical Research: Space Physics Pages: 7740 - 7751 DOI: 10.1002/2013JA019260 Available at: http://doi.wiley.com/10.1002/2013JA019260
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Authors: Ni Binbin, Li Wen, Thorne Richard M, Bortnik Jacob, Ma Qianli, et al.
Title: Resonant scattering of energetic electrons by unusual low-frequency hiss
Abstract: We quantify the resonant scattering effects of the unusual low-frequency dawnside plasmaspheric hiss observed on 30 September 2012 by the Van Allen Probes. In contrast to normal (~100–2000 Hz) hiss emissions, this unusual hiss event contained most of its wave power at ~20–200 Hz. Compared to the scattering by normal hiss, the unusual hiss scattering speeds up the loss of ~50–200 keV electrons and produces more pronounced pancake distributions of ~50–100 keV electrons. It is demonstrated that such unusual low-frequency hiss, even with a duration of a couple of hours, plays a particularly important role in the decay and loss process of energetic electrons, resulting in shorter electron lifetimes for ~50–400 keV electrons than normal hiss, and should be carefully incorpora. . .
Date: 03/2014 Publisher: Geophysical Research Letters Pages: 1854 - 1861 DOI: 10.1002/2014GL059389 Available at: http://doi.wiley.com/10.1002/2014GL059389
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Authors: Ni Binbin, Zou Zhengyang, Fu Song, Cao Xing, Gu Xudong, et al.
Title: Resonant Scattering of Radiation Belt Electrons by Off-Equatorial Magnetosonic Waves
Abstract: Fast magnetosonic (MS) waves are commonly regarded as electromagnetic waves that are characteristically confined within ±3° of the geomagnetic equator. We report two typical off-equatorial MS events observed by Van Allen Probes, that is, the 8 May 2014 event that occurred at the geomagnetic latitudes of 7.5°–9.2° both inside and outside the plasmasphere with the wave amplitude up to 590 pT and the 9 January 2014 event that occurred at the latitudes of—(15.7°–17.5°) outside the plasmasphere with a smaller amplitude about 81 pT. Detailed test particle simulations quantify the electron resonant scattering rates by the off-equatorial MS waves to find that they can cause the pitch angle scattering and momentum diffusion of radiation belt electrons with equatorial pitch angles < ~75. . .
Date: 02/2018 Publisher: Geophysical Research Letters Pages: 1228 - 1236 DOI: 10.1002/grl.v45.310.1002/2017GL075788 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017GL075788/full
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Authors: Yu Xiongdong, Yuan Zhigang, Li Haimeng, Huang Shiyong, Wang Dedong, et al.
Title: Response of banded whistler-mode waves to the enhancement of solar wind dynamic pressure in the inner Earth's magnetosphere
Abstract: With observations of Van Allen Probe A, in this letter we display a typical event where banded whistler waves shifted up their frequencies with frequency bands broadening as a response to the enhancement of solar wind dynamic pressure. Meanwhile, the anisotropy of electrons with energies about several tens of keV was observed to increase. Through the comparison of the calculated wave growth rates and observed wave spectral intensity, we suggest that those banded whistler waves observed with frequencies shifted up and frequency bands broadening could be locally excited by these hot electrons with increased anisotropy. The current study provides a great in situ evidence for the influence on frequencies of banded whistler waves by the enhancement of solar wind dynamic pressures, which reveals. . .
Date: Mar-08-2020 Publisher: Geophysical Research Letters DOI: 10.1029/2018GL078849 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL078849
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Authors: Motoba T., Ohtani S, Gkioulidou M., Ukhorskiy A., Mitchell D G, et al.
Title: Response of Different Ion Species to Local Magnetic Dipolarization Inside Geosynchronous Orbit
Abstract: This paper examines how hydrogen, helium and oxygen (H, He and O) ion fluxes at 1–1000 keV typically respond to local magnetic dipolarization inside geosynchronous orbit (GEO). We extracted 144 dipolarizations which occurred at magnetic inclination > 30° from the 2012–2016 tail seasons' observations of the Van Allen Probes spacecraft and then defined typical flux changes of these ion species by performing a superposed epoch analysis. On average, the dipolarization inside GEO is accompanied by a precursory transient decrease in the northward magnetic field component, transient impulsive enhancement in the westward electric field component, and decrease (increase) in the proton density (temperature). The coincident ion species experience an energy‐dependent flux change, consisting of . . .
Date: 06/2018 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2018JA025557 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JA025557
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Authors: Turner D. L., Kilpua E. K. J., Hietala H., Claudepierre S G, O'Brien T P, et al.
Title: The Response of Earth's Electron Radiation Belts to Geomagnetic Storms: Statistics From the Van Allen Probes Era Including Effects From Different Storm Drivers
Abstract: A statistical study was conducted of Earth's radiation belt electron response to geomagnetic storms using NASA's Van Allen Probes mission. Data for electrons with energies ranging from 30 keV to 6.3 MeV were included and examined as a function of L‐shell, energy, and epoch time during 110 storms with SYM‐H ≤−50 nT during September 2012 to September 2017 (inclusive). The radiation belt response revealed clear energy and L‐shell dependencies, with tens of keV electrons enhanced at all L‐shells (2.5 ≤ L ≤ 6) in all storms during the storm commencement and main phase and then quickly decaying away during the early recovery phase, low hundreds of keV electrons enhanced at lower L‐shells (~3 ≤ L ≤ ~4) in upward of 90% of all storms and then decaying gradually during the rec. . .
Date: 01/2019 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2018JA026066 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JA026066
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Authors: Xiong Ying, Xie Lun, Chen Lunjin, Ni Binbin, Fu Suiyan, et al.
Title: The Response of the Energy Content of the Outer Electron Radiation Belt to Geomagnetic Storms
Abstract: Using the data from the Van Allen Probe‐A spacecraft, the variability of the total outer radiation belt (2.5300 keV) is investigated for the first time during 51 isolated storms spanning from October 2012 to May 2017. The statistical results show that the TRBEEC exhibits no‐change in 20% of the storms and gets enhanced during 80% of them. The sub‐relativistic electrons (300‐500 keV) and relativistic electrons (0.5‐2.0 MeV) equally contribute to the TRBEEC during the main phases, while in the recovery phases, the relativistic electrons contribute up to 80% of the TRBEEC. The results of the superposed epoch analysis of the solar wind parameters and geomagnetic indices indicate that the TRBEEC enhancement events prefe. . .
Date: 09/2018 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2018JA025475 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JA025475
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Authors: Claudepierre S G, O'Brien T P, Looper M D, Blake J B, Fennell J. F., et al.
Title: A Revised Look at Relativistic Electrons in the Earth's Inner Radiation Zone and Slot Region
Abstract: We describe a new, more accurate procedure for estimating and removing inner zone background contamination from Van Allen Probes Magnetic Electron Ion Spectrometer (MagEIS) radiation belt measurements. This new procedure is based on the underlying assumption that the primary source of background contamination in the electron measurements at L shells less than three, energetic inner belt protons, is relatively stable. Since a magnetic spectrometer can readily distinguish between foreground electrons and background signals, we are able to exploit the proton stability to construct a model of the background contamination in each MagEIS detector by only considering times when the measurements are known to be background dominated. We demonstrate, for relativistic electron measurements in the inn. . .
Date: 01/2019 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2018JA026349 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JA026349
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Authors: Zhao H., Li X, Baker D N, Claudepierre S G, Fennell J. F., et al.
Title: Ring current electron dynamics during geomagnetic storms based on the Van Allen Probes measurements
Abstract: Based on comprehensive measurements from Helium, Oxygen, Proton, and Electron Mass Spectrometer Ion Spectrometer, Relativistic Electron-Proton Telescope, and Radiation Belt Storm Probes Ion Composition Experiment instruments on the Van Allen Probes, comparative studies of ring current electrons and ions are performed and the role of energetic electrons in the ring current dynamics is investigated. The deep injections of tens to hundreds of keV electrons and tens of keV protons into the inner magnetosphere occur frequently; after the injections the electrons decay slowly in the inner belt but protons in the low L region decay very fast. Intriguing similarities between lower energy protons and higher-energy electrons are also found. The evolution of ring current electron and ion energy densi. . .
Date: 04/2016 Publisher: Journal of Geophysical Research: Space Physics Pages: 3333 - 3346 DOI: 10.1002/2016JA022358 Available at: http://doi.wiley.com/10.1002/2016JA022358
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Authors: Kim Hyomin, Gerrard Andrew J., Lanzerotti Louis J., Soto-Chavez Rualdo, Cohen Ross J., et al.
Title: Ring Current He-Ion Control by Bounce Resonant ULF Waves
Abstract: Ring current energy He-ion (∼65 keV to ∼520 keV) differential flux data from the Radiation Belt Storm Probe Ion Composition Experiment (RBSPICE) instrument aboard the Van Allan Probes spacecraft show considerable variability during quiet solar wind and geomagnetic time periods. Such variability is apparent from orbit to orbit (∼9 hours) of the spacecraft and is observed to be ∼50–100% of the nominal flux. Using data from the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) instrument, also aboard the Van Allen Probes spacecraft, we identify that a dominant source of this variability is from ULF waveforms with periods of 10's of sec. These periods correspond to the bounce resonant timescales of the ring current He-ions being measured by RBSPICE. A stat. . .
Date: 09/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA023958 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA023958/full
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Authors: Godinez Humberto C, Yu Yiqun, Lawrence Eric, Henderson Michael G., Larsen Brian A, et al.
Title: Ring Current Pressure Estimation with RAM-SCB using Data Assimilation and Van Allen Probe Flux Data
Abstract: Capturing and subsequently modeling the influence of tail plasma injections on the inner magnetosphere is important for understanding the formation and evolution of the ring current. In this study, the ring current distribution is estimated with the Ring Current-Atmosphere Interactions Model with Self-Consistent Magnetic field (RAM-SCB) using, for the first time, data assimilation techniques and particle flux data from the Van Allen Probes. The state of the ring current within the RAM-SCB model is corrected via an ensemble based data assimilation technique by using proton flux from one of the Van Allen Probes, to capture the enhancement of the ring current following an isolated substorm event on July 18, 2013. The results show significant improvement in the estimation of the ring current p. . .
Date: 11/2016 Publisher: Geophysical Research Letters DOI: 10.1002/2016GL071646 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016GL071646/full
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Authors: Olifer L., Mann I. R., Morley S. K., Ozeke L. G., and Choi D.
Title: On the role of last closed drift shell dynamics in driving fast losses and Van Allen radiation belt extinction
Abstract: We present observations of very fast radiation belt loss as resolved using high‐time resolution electron flux data from the constellation of Global Positioning System (GPS) satellites. The timescale of these losses is revealed to be as short as ∼0.5 − 2 hours during intense magnetic storms, with some storms demonstrating almost total loss on these timescales and which we characterize as radiation belt extinction. The intense March 2013 and March 2015 storms both show such fast extinction, with a rapid recovery, while the September 2014 storm shows fast extinction but no recovery for around two weeks. By contrast, the moderate September 2012 storm which generated a three radiation belt morphology shows more gradual loss. We compute the last closed drift shell (LCDS) for each of these . . .
Date: 04/2018 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2018JA025190 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JA025190
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Authors: Yu Yiqun, Jordanova Vania, Welling Dan, Larsen Brian, Claudepierre Seth G., et al.
Title: The role of ring current particle injections: Global simulations and Van Allen Probes observations during 17 March 2013 storm
Abstract: We simulate substorm injections observed by the Van Allen Probes during the 17 March 2013 storm using a self-consistent coupling between the ring current model RAM-SCB and the global MHD model BATS-R-US. This is a significant advancement compared to previous studies that used artificially imposed electromagnetic field pulses to mimic substorm dipolarization and associated inductive electric field. Several substorm dipolarizations and injections are reproduced in the MHD model, in agreement with the timing of shape changes in the AE/AL index. The associated inductive electric field transports plasma sheet plasma to geostationary altitudes, providing the boundary plasma source to the ring current model. It is found that impulsive plasma sheet injections, together with a large-scale convectio. . .
Date: 02/2014 Publisher: Geophysical Research Letters Pages: 1126 - 1132 DOI: 10.1002/2014GL059322 Available at: http://doi.wiley.com/10.1002/2014GL059322
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Authors: Gkioulidou Matina, Ukhorskiy A., Mitchell D G, Sotirelis T., Mauk B., et al.
Title: The role of small-scale ion injections in the buildup of Earth's ring current pressure: Van Allen Probes observations of the March 17 th , 2013 storm
Abstract: Energetic particle transport into the inner magnetosphere during geomagnetic storms is responsible for significant plasma pressure enhancement, which is the driver of large-scale currents that control the global electrodynamics within the magnetosphere-ionosphere system. Therefore, understanding the transport of plasma from the tail deep into the near-Earth magnetosphere, as well as the energization processes associated with this transport, is essential for a comprehensive knowledge of the near-Earth space environment. During the main phase of a geomagnetic storm on March 17th 2013 (minimum Dst ~ −137 nT), the Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) instrument on the Van Allen Probes observed frequent, small-scale proton injections deep into the inner nightsi. . .
Date: 09/2014 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2014JA020096 Available at: http://doi.wiley.com/10.1002/2014JA020096
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Authors: Califf S., Li X., Zhao H., Kellerman A., Sarris T. E., et al.
Title: The role of the convection electric field in filling the slot region between the inner and outer radiation belts
Abstract: The Van Allen Probes have reported frequent flux enhancements of 100s keV electrons in the slot region, with lower energy electrons exhibiting more dynamic behavior at lower L shells. Also, in situ electric field measurements from the Combined Release and Radiation Effects Satellite, Time History of Events and Macroscale Interactions during Substorms (THEMIS), and the Van Allen Probes have provided evidence for large-scale electric fields at low L shells during active times. We study an event on 19 February 2014 where hundreds of keV electron fluxes were enhanced by orders of magnitude in the slot region and electric fields of 1–2 mV/m were observed below L = 3. Using a 2-D guiding center particle tracer and a simple large-scale convection electric field model, we demonstrate that . . .
Date: 02/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023657 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA023657/full
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Authors: Takahashi Kazue, Hartinger Michael D., Vellante Massimo, Heilig ázs, Lysak Robert L, et al.
Title: Roles of Flow Braking, Plasmaspheric Virtual Resonances, and Ionospheric Currents in Producing Ground Pi2 Pulsations
Abstract: In one model, Pi2 pulsations are driven pulse by pulse by fast mode pulses that are launched as periodic bursty bulk flows brake when they approach the Earth. We have examined this model by analyzing data from multiple spacecraft and ground magnetometers for a Pi2 pulsation event. During the event, which started at ∼2226 UT on 8 November 2014, Time History of Events and Macroscale Interactions during Substorms (THEMIS)‐D detected an ∼2 min period plasma bulk flow oscillation in the near‐Earth magnetotail, while THEMIS‐E and Van Allen Probes‐B, both located on the nightside just earthward of the electron plasmapause, detected a Pi2 pulsation consisting of a 10 mHz oscillation in the azimuthal component of the electric field and a 19‐mHz oscillation in the compressional compone. . .
Date: 09/2018 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2018JA025664 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JA025664
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Authors: Hwang J., Shin D. K., Yoon P. H., Kurth W S, Larsen B A, et al.
Title: Roles of hot electrons in generating upper-hybrid waves in the earth's radiation belt
Abstract: Electrostatic fluctuations near upper-hybrid frequency, which are sometimes accompanied by multiple-harmonic electron cyclotron frequency bands above and below the upper-hybrid frequency, are common occurrences in the Earth's radiation belt, as revealed through the twin Van Allen Probe spacecrafts. It is customary to use the upper-hybrid emissions for estimating the background electron density, which in turn can be used to determine the plasmapause locations, but the role of hot electrons in generating such fluctuations has not been discussed in detail. The present paper carries out detailed analyses of data from the Waves instrument, which is part of the Electric and Magnetic Field Instrument Suite and Integrated Science suite onboard the Van Allen Probes. Combined with the theoretical ca. . .
Date: 06/2017 Publisher: Physics of Plasmas Pages: 062904 DOI: 10.1063/1.4984249 Available at: http://aip.scitation.org/doi/10.1063/1.4984249
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Authors: Li L. Y., Yu J., Cao J. B., Yang J. Y., Li X, et al.
Title: Roles of whistler-mode waves and magnetosonic waves in changing the outer radiation belt and the slot region
Abstract: Using the Van Allen Probe long-term (2013 – 2015) observations and quasi-linear simulations of wave-particle interactions, we examine the combined or competing effects of whistler-mode waves (chorus or hiss) and magnetosonic (MS) waves on energetic (<0.5 MeV) and relativistic (>0.5 MeV) electrons inside and outside the plasmasphere. Although whistler-mode chorus waves and MS waves can singly or jointly accelerate electrons from the hundreds of keV energy to the MeV energy in the low-density trough, most of the relativistic electron enhancement events are best correlated with the chorus wave emissions outside the plasmapause. Inside the plasmasphere, intense plasmaspheric hiss can cause the net loss of relativistic electrons via persistent pitch angle scattering, regardless of whether. . .
Date: 04/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023634 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA023634/full
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Authors: Ukhorskiy A Y, Sitnov M I, Mitchell D G, Takahashi K, Lanzerotti L J, et al.
Title: Rotationally driven ‘zebra stripes’ in Earth’s inner radiation belt
Abstract: Structured features on top of nominally smooth distributions of radiation-belt particles at Earth have been previously associated with particle acceleration and transport mechanisms powered exclusively by enhanced solar-wind activity1, 2, 3, 4. Although planetary rotation is considered to be important for particle acceleration at Jupiter and Saturn5, 6, 7, 8, 9, the electric field produced in the inner magnetosphere by Earth’s rotation can change the velocity of trapped particles by only about 1–2 kilometres per second, so rotation has been thought inconsequential for radiation-belt electrons with velocities of about 100,000 kilometres per second. Here we report that the distributions of energetic electrons across the entire spatial extent of Earth’s inner radiation belt are organize. . .
Date: 01/2014 Publisher: Nature Pages: 338 - 340 DOI: 10.1038/nature13046 Available at: http://www.nature.com/doifinder/10.1038/nature13046
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Authors: Yu Xiongdong, and Yuan Zhigang
Title: Saturation Characteristics of Parallel EMIC Waves in the Inner Magnetosphere
Abstract: In this letter, detailed evolution process of parallel electromagnetic ion cyclotron waves in the inner magnetosphere has been investigated through quasilinear theory. A new saturation has been found to occur after the usual first saturation. During the interval between these two saturations, the energy transfers from H+ band to He+ band electromagnetic ion cyclotron waves. Moreover, through a best fitting, we obtain new model parameters for the anisotropy‐beta inverse relation of hot H+, which identifies the threshold of ion cyclotron instabilities in the inner magnetosphere. In situ observations of the Van Allen Probe mission also verify these new model parameters. Therefore, our results reveal the evolution process and saturation characteristics of parallel electromagnetic ion cyclotr. . .
Date: 07/2019 Publisher: Geophysical Research Letters DOI: 10.1029/2019GL083630 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019GL083630
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Authors: Kim S.-I., Kim K.-H., Kwon H.-J., Jin H., Lee E., et al.
Title: SC-associated electric field variations in the magnetosphere and ionospheric convective flows
Abstract: We examine magnetic and electric field perturbations associated with a sudden commencement (SC), caused by an interplanetary (IP) shock passing over the Earth's magnetosphere on 16 February 2013. The SC was identified in the magnetic and electric field data measured at THEMIS-E (THE-E: MLT = 12.4, L = 6.3), Van Allen Probe-A (VAP-A: MLT = 3.2, L = 5.1), and Van Allen Probe-B (VAP-B: MLT = 0.2. L= 4.9) in the magnetosphere. During the SC interval, THE-E observed a dawnward-then-duskward electric (E) field perturbation around noon, while VAP-B observed a duskward E-field perturbation around midnight. VAP-A observed a dawnward-then-duskward E-field perturbation in the postmidnight sector, but the duration and magnitude of the dawnward E-perturbation are much shorter and weaker than that at TH. . .
Date: 10/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024611 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA024611/full
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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: Mauk B H, Fox N J, Kanekal S G, Kessel R L, Sibeck D G, et al.
Title: Science Objectives and Rationale for the Radiation Belt Storm Probes Mission
Abstract: The NASA Radiation Belt Storm Probes (RBSP) mission addresses how populations of high energy charged particles are created, vary, and evolve in space environments, and specifically within Earth’s magnetically trapped radiation belts. RBSP, with a nominal launch date of August 2012, comprises two spacecraft making in situ measurements for at least 2 years in nearly the same highly elliptical, low inclination orbits (1.1×5.8 RE, 10∘). The orbits are slightly different so that 1 spacecraft laps the other spacecraft about every 2.5 months, allowing separation of spatial from temporal effects over spatial scales ranging from ∼0.1 to 5 RE. The uniquely comprehensive suite of instruments, identical on the two spacecraft, measures all of the particle (electrons, ions, ion composition), fiel. . .
Date: 11/2013 Publisher: Space Science Reviews Pages: 3-27, DOI: 10.1007/s11214-012-9908-y Available at: http://link.springer.com/article/10.1007%2Fs11214-012-9908-y
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Authors: Min Kyungguk, Takahashi Kazue, Ukhorskiy Aleksandr Y., Manweiler Jerry W., Spence Harlan E., et al.
Title: Second harmonic poloidal waves observed by Van Allen Probes in the dusk-midnight sector
Abstract: This paper presents observations of ultralow-frequency (ULF) waves from Van Allen Probes. The event that generated the ULF waves occurred 2 days after a minor geomagnetic storm during a geomagnetically quiet time. Narrowband pulsations with a frequency of about 7 mHz with moderate amplitudes were registered in the premidnight sector when Probe A was passing through an enhanced density region near geosynchronous orbit. Probe B, which passed through the region earlier, did not detect the narrowband pulsations but only broadband noise. Despite the single-spacecraft measurements, we were able to determine various wave properties. We find that (1) the observed waves are a second harmonic poloidal mode propagating westward with an azimuthal wave number estimated to be ∼100; (2) the magnetic fi. . .
Date: 03/2017 Publisher: Journal of Geophysical Research: Space Physics Pages: 3013-3-39 DOI: 10.1002/2016JA023770 Available at: onlinelibrary.wiley.com/doi/10.1002/2016JA023770/full
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Authors: Min Kyungguk, Takahashi Kazue, Ukhorskiy Aleksandr Y., Manweiler Jerry W., Spence Harlan E., et al.
Title: Second harmonic poloidal waves observed by Van Allen Probes in the dusk-midnight sector
Abstract: This paper presents observations of ultra-low frequency (ULF) waves from Van Allen Probes. The event that generated the ULF waves occurred two days after a minor geomagnetic storm during a geomagnetically quiet time. Narrowband pulsations with a frequency of about 7 mHz with moderate amplitudes were registered in the pre-midnight sector when Probe A was passing through an enhanced density region near geosynchronous orbit. Probe B, which passed through the region earlier, did not detect the narrowband pulsations but only broadband noise. Despite the single-spacecraft measurements, we were able to determine various wave properties. We find that (1) the observed waves are a second harmonic poloidal mode propagating westward with an azimuthal wave number estimated to be ∼100; (2) the magneti. . .
Date: 02/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023770 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA023770/full
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Authors: Cao Xing, Ni Binbin, Summers Danny, Shprits Yuri Y, Gu Xudong, et al.
Title: Sensitivity of EMIC Wave-Driven Scattering Loss of Ring Current Protons to Wave Normal Angle Distribution
Abstract: 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. For >10 keV protons, the field‐aligned propagation approximation results in a pronounced underestimate of the scattering of intermediate equatorial pitch angle protons and overestimates the scattering of high equatorial pitch angle protons by orders of magnitude. Ou. . .
Date: 01/2019 Publisher: Geophysical Research Letters Pages: 590 - 598 DOI: 10.1029/2018GL081550 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL081550
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Authors: Liu Nigang, Su Zhenpeng, Gao Zhonglei, Reeves G D, Zheng Huinan, et al.
Title: Shock-induced disappearance and subsequent recovery of plasmaspheric hiss: Coordinated observations of RBSP, THEMIS and POES satellites
Abstract: Plasmaspheric hiss is an extremely low frequency whistler-mode emission contributing significantly to the loss of radiation belt electrons. There are two main competing mechanisms for the generation of plasmaspheric hiss: excitation by local instability in the outer plasmasphere and origination from chorus outside the plasmasphere. Here, on the basis of the analysis of an event of shock-induced disappearance and subsequent recovery of plasmaspheric hiss observed by RBSP, THEMIS and POES missions, we attempt to identify its dominant generation mechanism. In the pre-shock plasmasphere, the local electron instability was relatively weak and the hiss waves with bidirectional Poynting fluxes mainly originated from the dayside chorus waves. On arrival of the shock, the removal of pre-existing da. . .
Date: 10/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024470 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA024470/full
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Authors: Foster J. C., Wygant J R, Hudson M K, Boyd A. J., Baker D N, et al.
Title: Shock-Induced Prompt Relativistic Electron Acceleration In the Inner Magnetosphere
Abstract: We present twin Van Allen Probes spacecraft observations of the effects of a solar wind shock impacting the magnetosphere on 8 October 2013. The event provides details both of the accelerating electric fields associated with the shock and the response of inner magnetosphere electron populations across a broad range of energies. During this period the two Van Allen Probes observed shock effects from the vantage point of the dayside magnetosphere at radial positions of L=3 and L=5, at the location where shock-induced acceleration of relativistic electrons occurs. The extended (~1 min) duration of the accelerating electric field across a broad extent of the dayside magnetosphere, coupled with energy dependent relativistic electron gradient drift velocities, selects a preferred range of energi. . .
Date: 01/2015 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2014JA020642 Available at: http://doi.wiley.com/10.1002/2014JA020642
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Authors: Lejosne Solène, and Mozer F S
Title: Shorting Factor In‐Flight Calibration for the Van Allen Probes DC Electric Field Measurements in the Earth's Plasmasphere
Abstract: Satellite‐based direct electric field measurements deliver crucial information for space science studies. Yet they require meticulous design and calibration. In‐flight calibration of double‐probe instruments is usually presented in the most common case of tenuous plasmas, where the presence of an electrostatic structure surrounding the charged spacecraft alters the geophysical electric field measurements. To account for this effect and the uncertainty in the boom length, the measured electric field is multiplied by a parameter called the shorting factor (sf). In the plasmasphere, the Debye length is very small in comparison with spacecraft dimension, and there is no shorting of the electric field measurements (sf = 1). However, the electric field induced by spacecraft motion greatly . . .
Date: 04/2019 Publisher: Earth and Space Science Pages: 646 - 654 DOI: 10.1029/2018EA000550 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018EA000550
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Authors: Aseev N. A., Shprits Y Y, Drozdov A. Y., Kellerman A. C., Usanova M. E., et al.
Title: Signatures of Ultrarelativistic Electron Loss in the Heart of the Outer Radiation Belt Measured by Van Allen Probes
Abstract: Up until recently, signatures of the ultrarelativistic electron loss driven by electromagnetic ion cyclotron (EMIC) waves in the Earth's 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 Van Allen Probe particle data as a function of time and three adiabatic invariants between 9 October and 29 November 2012. New local minimums in the profiles are accompanied by the narrowing of normalized pitch angle distributions and ground-based detection of EMIC waves. Such a cor. . .
Date: 09/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024485 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA024485/full
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Authors: Hudson M K, Baker D N, Goldstein J, Kress B T, Paral J., et al.
Title: Simulated magnetopause losses and Van Allen Probe flux dropouts
Abstract: Three radiation belt flux dropout events seen by the Relativistic Electron Proton Telescope soon after launch of the Van Allen Probes in 2012 (Baker et al., 2013a) have been simulated using the Lyon-Fedder-Mobarry MHD code coupled to the Rice Convection Model, driven by measured upstream solar wind parameters. MHD results show inward motion of the magnetopause for each event, along with enhanced ULF wave power affecting radial transport. Test particle simulations of electron response on 8 October, prior to the strong flux enhancement on 9 October, provide evidence for loss due to magnetopause shadowing, both in energy and pitch angle dependence. Severe plasmapause erosion occurred during ~ 14 h of strongly southward interplanetary magnetic field Bz beginning 8 October coincident with. . .
Date: 02/2014 Publisher: Geophysical Research Letters Pages: 1113 - 1118 DOI: 10.1002/2014GL059222 Available at: http://doi.wiley.com/10.1002/2014GL059222
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Authors: Hudson Mary, Jaynes Allison, Kress Brian, Li Zhao, Patel Maulik, et al.
Title: Simulated prompt acceleration of multi-MeV electrons by the 17 March 2015 interplanetary shock
Abstract: Prompt enhancement of relativistic electron flux at L = 3−5 has been reported from Van Allen Probes Relativistic Electron Proton Telescope (REPT) measurements associated with the 17 March 2015 interplanetary shock compression of the dayside magnetosphere. Acceleration by ∼ 1 MeV is inferred on less than a drift time scale as seen in prior shock compression events, which launch a magetosonic azimuthal electric field impulse tailward. This impulse propagates from the dayside around the flanks accelerating electrons in drift resonance at the dusk flank. Such longitudinally localized acceleration events produce a drift echo signature which was seen at >1 MeV energy on both Van Allen Probe spacecraft, with sustained observations by Probe B outbound at L = 5 at 2100 MLT at the time of impuls. . .
Date: 09/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024445 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA024445/full
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Authors: Ma Q, Li W, Thorne R M, Nishimura Y., Zhang X.-J., et al.
Title: Simulation of energy-dependent electron diffusion processes in the Earth's outer radiation belt
Abstract: The radial and local diffusion processes induced by various plasma waves govern the highly energetic electron dynamics in the Earth's radiation belts, causing distinct characteristics in electron distributions at various energies. In this study, we present our simulation results of the energetic electron evolution during a geomagnetic storm using the University of California, Los Angeles 3-D diffusion code. Following the plasma sheet electron injections, the electrons at different energy bands detected by the Magnetic Electron Ion Spectrometer (MagEIS) and Relativistic Electron Proton Telescope (REPT) instruments on board the Van Allen Probes exhibit a rapid enhancement followed by a slow diffusive movement in differential energy fluxes, and the radial extent to which electrons can penetra. . .
Date: 05/2016 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA022507 Available at: http://doi.wiley.com/10.1002/2016JA022507
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Authors: Patel Maulik, Li Zhao, Hudson Mary, Claudepierre Seth, and Wygant John
Title: Simulation of Prompt Acceleration of Radiation Belt Electrons During the 16 July 2017 Storm
Abstract: We investigate the prompt enhancement of radiation belt electron flux observed by the Relativistic Electron Proton Telescope instrument on board Van Allen Probes following the 16 July 2017 CME‐shock compression using MHD‐test particle simulations. The prompt enhancements can be explained by the source population interacting with the azimuthally directed electric field impulses induced by CME‐shock compressions of the dayside magnetopause. Electrons in drift resonance with the electric field impulse were accelerated by ∼ 0.6 MeV on a drift period timescale (in minutes) as the impulse propagated from the dayside to the nightside around the flanks of the magnetosphere. MHD test particle simulation of energization and drift phase bunching, due to the bipolar electric field that accompa. . .
Date: 06/2019 Publisher: Geophysical Research Letters DOI: 10.1029/2019GL083257 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019GL083257
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Authors: Goldstein J, De Pascuale S., Kletzing C., Kurth W., Genestreti K. J., et al.
Title: Simulation of Van Allen Probes Plasmapause Encounters
Abstract: We use an E × B-driven plasmapause test particle (PTP) simulation to provide global contextual information for in situ measurements by the Van Allen Probes (RBSP) during 15–20 January 2013. During 120 h of simulation time beginning on 15 January, geomagnetic activity produced three plumes. The third and largest simulated plume formed during enhanced convection on 17 January, and survived as a rotating, wrapped, residual plume for tens of hours. To validate the simulation, we compare its output with RBSP data. Virtual RBSP satellites recorded 28 virtual plasmapause encounters during 15–19 January. For 26 of 28 (92%) virtual crossings, there were corresponding actual RBSP encounters with plasmapause density gradients. The mean difference in encounter time between model and data is. . .
Date: 09/2014 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2014JA020252 Available at: http://doi.wiley.com/10.1002/2014JA020252
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Authors: Eshetu W. W., Lyon J G, Hudson M K, and Wiltberger M. J.
Title: Simulations of Electron Energization and Injection by BBFs Using High-Resolution LFM MHD Fields
Abstract: We study electron injection and energization by bursty bulk flows (BBFs), by tracing electron trajectories using magnetohydrodynamic (MHD) field output from the Lyon‐Fedder‐Mobarry (LFM) code. The LFM MHD simulations were performed using idealized solar wind conditions to produce BBFs. We show that BBFs can inject energetic electrons of few to 100 keV from the magnetotatail beyond −24 RE to inward of geosynchronous, while accelerating them in the process. We also show the dependence of energization and injection on the initial relative position of the electrons to the magnetic field structure of the BBF, the initial pitch angle, and the initial energy. In addition, we have shown that the process can be nonadiabatic with violation of the first adiabatic invariant (μ). Further, we d. . .
Date: 02/2019 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2018JA025789 Available at: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018JA025789
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Authors: Jordanova V K, Yu Y., Niehof J T, Skoug R M, Reeves G D, et al.
Title: Simulations of inner magnetosphere dynamics with an expanded RAM-SCB model and comparisons with Van Allen Probes observations
Abstract: Simulations from our newly expanded ring current-atmosphere interactions model with self-consistent magnetic field (RAM-SCB), now valid out to 9 RE, are compared for the first time with Van Allen Probes observations. The expanded model reproduces the storm time ring current buildup due to the increased convection and inflow of plasma from the magnetotail. It matches Magnetic Electron Ion Spectrometer (MagEIS) observations of the trapped high-energy (>50 keV) ion flux; however, it underestimates the low-energy (<10 keV) Helium, Oxygen, Proton, and Electron (HOPE) observations. The dispersed injections of ring current ions observed with the Energetic particle, Composition, and Thermal plasma (ECT) suite at high (>20 keV) energy are better reproduced using a high-resolution convection model. . . .
Date: 04/2014 Publisher: Geophysical Research Letters Pages: 2687 - 2694 DOI: 10.1002/2014GL059533 Available at: http://doi.wiley.com/10.1002/2014GL059533
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Authors: De Pascuale S., Jordanova V K, Goldstein J, Kletzing C A, Kurth W S, et al.
Title: Simulations of Van Allen Probes Plasmaspheric Electron Density Observations
Abstract: We simulate equatorial plasmaspheric electron densities using a physics‐based model (Cold PLasma, CPL; used in the ring current‐atmosphere interactions model) of the source and loss processes of refilling and erosion driven by empirical inputs. The performance of CPL is evaluated against in situ measurements by the Van Allen Probes (Radiation Belt Storm Probes) for two events: the 31 May to 5 June and 15 to 20 January 2013 geomagnetic storms observed in the premidnight and postmidnight magnetic local time (MLT) sectors, respectively. Overall, CPL reproduces the radial extent of the plasmasphere to within a mean absolute difference of urn:x-wiley:jgra:media:jgra54637:jgra54637-math-0001 L. The model electric field responsible for E × B convection and the parameterization of geomagn. . .
Date: 11/2018 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2018JA025776 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JA025776
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Authors: Liu Nigang, Su Zhenpeng, Gao Zhonglei, Zheng Huinan, Wang Yuming, et al.
Title: Simultaneous disappearances of plasmaspheric hiss, exohiss, and chorus waves triggered by a sudden decrease in solar wind dynamic pressure
Abstract: Magnetospheric whistler mode waves are of great importance in the radiation belt electron dynamics. Here on the basis of the analysis of a rare event with the simultaneous disappearances of whistler mode plasmaspheric hiss, exohiss, and chorus triggered by a sudden decrease in the solar wind dynamic pressure, we provide evidences for the following physical scenarios: (1) nonlinear generation of chorus controlled by the geomagnetic field inhomogeneity, (2) origination of plasmaspheric hiss from chorus, and (3) leakage of plasmaspheric hiss into exohiss. Following the reduction of the solar wind dynamic pressure, the dayside geomagnetic field configuration with the enhanced inhomogeneity became unfavorable for the generation of chorus, and the quenching of chorus directly caused the disappea. . .
Date: 01/2017 Publisher: Geophysical Research Letters Pages: 52 - 61 DOI: 10.1002/2016GL071987 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016GL071987/full
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Authors:
Title: Simultaneous disappearances of plasmaspheric hiss, exohiss, and chorus waves triggered by a sudden decrease in solar wind dynamic pressure
Abstract: Magnetospheric whistler mode waves are of great importance in the radiation belt electron dynamics. Here on the basis of the analysis of a rare event with the simultaneous disappearances of whistler mode plasmaspheric hiss, exohiss, and chorus triggered by a sudden decrease in the solar wind dynamic pressure, we provide evidences for the following physical scenarios: (1) nonlinear generation of chorus controlled by the geomagnetic field inhomogeneity, (2) origination of plasmaspheric hiss from chorus, and (3) leakage of plasmaspheric hiss into exohiss. Following the reduction of the solar wind dynamic pressure, the dayside geomagnetic field configuration with the enhanced inhomogeneity became unfavorable for the generation of chorus, and the quenching of chorus directly caused the disappea. . .
Date: 01/2017 Publisher: Geophysical Research Letters DOI: 10.1002/2016GL071987 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016GL071987
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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: Mozer F S, Agapitov O. V., Blake J B, and Vasko I. Y.
Title: SIMULTANEOUS OBSERVATIONS OF LOWER BAND CHORUS EMISSIONS AT THE EQUATOR AND MICROBURST PRECIPITATING ELECTRONS IN THE IONOSPHERE
Abstract: On December 11, 2016 at 00:12:30 UT, Van Allen Probe-B, at the equator and near midnight, and AC6-B, in the ionosphere, were on magnetic field lines whose 100 km altitude foot points were separated by 600 km. Van Allen Probe-B observed a 30 second burst of lower band chorus waves (with maximum amplitudes >1 nT) at the same time that AC6-B observed intense microburst electrons in the loss cone. One-second averaged variations of the chorus intensity and the microburst electron flux were well-correlated. The low altitude electron flux expected from quasi-linear diffusion of the equatorial electrons by the equatorial chorus is in excellent agreement with the observed, one second averaged, low altitude electron flux. However the large amplitude, <0.5 second duration, low altitude electron pulse. . .
Date: 12/2017 Publisher: Geophysical Research Letters DOI: 10.1002/2017GL076120 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017GL076120/full
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Authors: Ghamry E., Kim K.-H., Kwon H.-J., Lee D.-H., Park J.-S., et al.
Title: Simultaneous Pi2 observations by the Van Allen Probes inside and outside the plasmasphere
Abstract: Plasmaspheric virtual resonance (PVR) model has been proposed as one of source mechanisms for low-latitude Pi2 pulsations. Since PVR-associated Pi2 pulsations are not localized inside the plasmasphere, simultaneous multipoint observations inside and outside the plasmasphere require to test the PVR model. Until now, however, there are few studies using simultaneous multisatellite observations inside and outside the plasmasphere for understanding the radial structure of Pi2 pulsation. In this study, we focus on the Pi2 event observed at low-latitude Bohyun (BOH, L = 1.35) ground station in South Korea in the postmidnight sector (magnetic local time (MLT) = 3.0) for the interval from 1730 to 1900 UT on 12 March 2013. By using electron density derived from the frequency of the upper hybrid wav. . .
Date: 05/2015 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2015JA021095 Available at: http://doi.wiley.com/10.1002/2015JA021095
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Authors: Yuan Zhigang, Yu Xiongdong, Ouyang Zhihai, Yao Fei, Huang Shiyong, et al.
Title: Simultaneous trapping of EMIC and MS waves by background plasmas
Abstract: Electromagnetic ion cyclotron waves and fast magnetosonic waves are found to be simultaneously modulated by background plasma density: both kinds of waves were observed in high plasma density regions but vanished in low density regions. Theoretical analysis based on Snell's law and linear growth theory have been utilized to investigate the physical mechanisms driving such modulation. It is suggested that the modulation of fast magnetosonic waves might be due to trapping by plasma density structures, which results from a conservation of the parameter Q during their propagation. Here Q = nrsinψ, with n the refractive index, r the radial distance, and ψ the wave azimuthal angle. As for electromagnetic ion cyclotron waves, the modulation might be owed to the ion composition difference betwee. . .
Date: 02/2019 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2018JA026149 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JA026149
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Authors: O'Brien T P, Mazur J E, and Looper M D
Title: Solar Energetic Proton Access to the Magnetosphere During the 10–14 September 2017 Particle Event
Abstract: We explore the penetration of >60 MeV protons into the magnetosphere during the 10–14 September 2017 solar energetic particle event. Solar energetic particles can cause single event effects and total dose degradation in spacecraft electronics. Therefore, it is important for satellite anomaly analysis to understand how deep into the magnetosphere these particles penetrate. Whereas most studies of geomagnetic cutoffs use low‐altitude data, we use data from the Relativistic Proton Spectrometer on National Aeronautics and Space Administration's Van Allen Probes, which is in a high‐altitude, elliptical orbit. We determine how the penetration depends on particle energy, location, and direction of incidence. We evaluate multiple published models of the geomagnetic cutoff to determine how we. . .
Date: 08/2018 Publisher: Space Weather DOI: 10.1029/2018SW001960 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018SW001960
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Authors: Thaller S. A., Wygant J R, Cattell C. A., Breneman A. W., Tyler E., et al.
Title: Solar rotation period driven modulations of plasmaspheric density and convective electric field in the inner magnetosphere
Abstract: This paper presents the first analysis of Van Allen Probes measurements of the cold plasma density and electric field in the inner magnetosphere to show that intervals of strong modulation at the solar rotation period occur in the locations of the outer plasmasphere and plasmapause (~0.7 RE peak‐to‐peak), in the large‐scale electric field (~0.24 mV/m peak‐to‐peak), and in the cold plasma density (~250 cm‐3 – ~70 cm‐3 peak‐to‐peak). Solar rotation modulation of the inner magnetosphere is more apparent in the declining phase of the solar cycle than near solar maximum. The periodicities in these parameters are compared to solar EUV irradiance, solar wind dawn‐dusk electric field, and Kp. The variations in the plasmapause location at the solar rotation period anti‐corre. . .
Date: 02/2019 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2018JA026365 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JA026365
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Authors: Li W, Thorne R M, Bortnik J, Baker D N, Reeves G D, et al.
Title: Solar wind conditions leading to efficient radiation belt electron acceleration: A superposed epoch analysis
Abstract: Determining preferential solar wind conditions leading to efficient radiation belt electron acceleration is crucial for predicting radiation belt electron dynamics. Using Van Allen Probes electron observations (>1 MeV) from 2012 to 2015, we identify a number of efficient and inefficient acceleration events separately to perform a superposed epoch analysis of the corresponding solar wind parameters and geomagnetic indices. By directly comparing efficient and inefficient acceleration events, we clearly show that prolonged southward Bz, high solar wind speed, and low dynamic pressure are critical for electron acceleration to >1 MeV energies in the heart of the outer radiation belt. We also evaluate chorus wave evolution using the superposed epoch analysis for the identified efficient and . . .
Date: 09/2015 Publisher: Geophysical Research Letters DOI: 10.1002/2015GL065342 Available at: http://onlinelibrary.wiley.com/wol1/doi/10.1002/2015GL065342/abstract
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Authors: Jaynes A.N., Baker D.N., Singer H.J., Rodriguez J.V., Loto'aniu T.M., et al.
Title: Source and Seed Populations for Relativistic Electrons: Their Roles in Radiation Belt Changes
Abstract: Strong enhancements of outer Van Allen belt electrons have been shown to have a clear dependence on solar wind speed and on the duration of southward interplanetary magnetic field. However, individual case study analyses also have demonstrated that many geomagnetic storms produce little in the way of outer belt enhancements and, in fact, may produce substantial losses of relativistic electrons. In this study, focused upon a key period in August-September 2014, we use GOES geostationary orbit electron flux data and Van Allen Probes particle and fields data to study the process of radiation belt electron acceleration. One particular interval, 13-22 September, initiated by a short-lived geomagnetic storm and characterized by a long period of primarily northward IMF, showed strong depletion of. . .
Date: 07/2015 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2015JA021234 Available at: http://doi.wiley.com/10.1002/2015JA021234
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Authors: Hudson M K
Title: Space physics: A fast lane in the magnetosphere
Abstract: A marriage between satellite observations and modelling has shown that acceleration of electrons in the magnetosphere can be explained by scattering of these particles by plasma oscillations known as chorus waves.
Date: 12/2013 Publisher: Nature Pages: 383 - 384 DOI: 10.1038/504383a Available at: http://www.nature.com/doifinder/10.1038/504383a
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Authors: Lanzerotti Louis J.
Title: Space Research and Space Weather: Some Personal Vignettes 1965 to Early 1980s
Abstract: Personal vignettes are given on early days of space research, space weather, and space advisory activities from 1965 to early 1980s.
Date: 04/2019 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2019JA026763 Available at: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019JA026763
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