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Book
Authors: Elkington Scot R, Takahashi K, Chi Peter J, Denton Richard E, and Lysak Robert L
Title: A review of ULF interactions with radiation belt electrons
Abstract: Energetic particle fluxes in the outer zone radiation belts can vary over orders of magnitude on a variety of timescales. Power at ULF frequencies, on the order of a few millihertz, have been associated with changes in flux levels among relativis- tic electrons comprising the outer zone of the radiation belts. Power in this part of the spectrum may occur as a result of a number of processes, including internally- generated waves induced by plasma instabilities, and externally generated processes such as shear instabilities at the flanks or compressive variations in the solar wind. Changes in the large-scale convective motion of the magnetosphere are another important class of externally driven variations with power at ULF wavelengths. The mechanism for interaction between ULF vari. . .
Date: Publisher: American Geophysical Union Pages: 177 - 193 DOI: 10.1029/169GM12 Available at: http://onlinelibrary.wiley.com/doi/10.1029/169GM12/summary
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Book Chapter
Authors: Burch L, Carovillano L, Antiochos K, Hudson M K, Elkington S R, et al.
Title: Simulation of Radiation Belt Dynamics Driven by Solar Wind Variations
Abstract: The rapid rise of relativistic electron fluxes inside geosynchronous orbit during the January 10-11, 1997, CME-driven magnetic cloud event has been simulated using a relativistic guiding center test particle code driven by out-put from a 3D global MHD simulation of the event. A comparison can be made of this event class, characterized by a moderate solar wind speed (< 600 km/s), and those commonly observed at the last solar maximum with a higher solar wind speed and shock accelerated solar energetic proton component. Relativistic electron flux increase occurred over several hours for the January event, during a period of prolonged southward IMF Bz more rapidly than the 1-2 day delay typical of flux increases driven by solar wind high speed stream interactions. Simulations of th. . .
Date: Publisher: American Geophysical Union Pages: 171 - 182 DOI: 10.1029/GM10910.1029/GM109p0171 Available at: http://onlinelibrary.wiley.com/doi/10.1029/GM109p0171/summary
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Conference Paper
Authors: Li W, Ni B, Thorne R M, Bortnik J, Green J C, et al.
Title: Calculation of whistler-mode wave intensity using energetic electron precipitation
Abstract: The energetic electron population measured by multiple low-altitude POES satellites is used to infer whistlermode wave amplitudes using a physics-based inversion technique. We validate this technique by quantitatively analyzing a conjunction event between the Van Allen Probes and POES, and find that the inferred hiss wave amplitudes from POES electron measurements agree remarkably well with directly measured hiss waves amplitudes. We also use this technique to construct the global distribution of chorus wave intensity with extensive coverage over a broad L-MLT region during the 8–9 October 2012 storm and demonstrate that the inferred chorus wave amplitudes agree well with conjugate measurements of chorus wave amplitudes from the Van Allen Probes. The evolution of the whistler-mode wave i. . .
Date: 08/2014 Publisher: IEEE DOI: 10.1109/URSIGASS.2014.6929965 Available at: http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6929965
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Authors: Nag Sreeja, LeMoigne Jacqueline, and de Weck Olivier
Title: Cost and risk analysis of small satellite constellations for earth observation
Abstract: Distributed Space Missions (DSMs) are gaining momentum in their application to Earth science missions owing to their ability to increase observation sampling in spatial, spectral, temporal and angular dimensions. Past literature from academia and industry have proposed and evaluated many cost models for spacecraft as well as methods for quantifying risk. However, there have been few comprehensive studies quantifying the cost for multiple spacecraft, for small satellites and the cost risk for the operations phase of the project which needs to be budgeted for when designing and building efficient architectures. This paper identifies the three critical problems with the applicability of current cost and risk models to distributed small satellite missions and uses data-based modeling to sugges. . .
Date: 03/2014 Publisher: IEEE DOI: 10.1109/AERO.2014.6836396 Available at: http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6836396
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Authors: Liggett William, Handiboe Jon, Theus Eugene, Hartka Ted, and Navid Hadi
Title: Design of a spacecraft integration and test facility at The Johns Hopkins University Applied Physics Laboratory
Abstract: The Johns Hopkins University Applied Physics Laboratory (JHU/APL) is dedicated to solving critical challenges as set forth by the National Aeronautics and Space Administration and the Department of Defense. JHU/APL participates fully in the nation's formulation of space science and exploration priorities, providing the needed science, engineering, and technology, including the production and operation of unique spacecraft, instruments, and subsystems.
Date: 03/2014 Publisher: IEEE DOI: 10.1109/AERO.2014.6836273 Available at: http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6836273
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Authors: Palo Scott E., Gerhardt David, Li Xinlin, Blum Lauren, Schiller Quintin, et al.
Title: One year of on-orbit performance of the Colorado Student Space Weather Experiment (CSSWE)
Abstract: The Colorado Student Space Weather Experiment is a 3-unit (10cm × 10cm × 30cm) CubeSat funded by the National Science Foundation and constructed at the University of Colorado (CU). The CSSWE science instrument, the Relativistic Electron and Proton Telescope integrated little experiment (REPTile), provides directional differential flux measurements of 0.5 to >3.3 MeV electrons and 9 to 40 MeV protons. Though a collaboration of 60+ multidisciplinary graduate and undergraduate students working with CU professors and engineers at the Laboratory for Atmospheric and Space Physics (LASP), CSSWE was designed, built, tested, and delivered in 3 years. On September 13, 2012, CSSWE was inserted to a 477 × 780 km, 65° orbit as a secondary payload on an Atlas V through the NASA Educational Launch of. . .
Date: 01/2014 Publisher: IEEE DOI: 10.1109/USNC-URSI-NRSM.2014.6928087 Available at: http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6928087
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Authors: Thorne R M, Li W, Ma Q, Ni B, and Bortnik J
Title: Radiation belt electron acceleration by chorus waves during the 17 March 2013 storm
Abstract: Local acceleration driven by whistler-mode chorus waves is suggested to be fundamentally important for accelerating seed electron population to ultra-relativistic energies in the outer radiation belt. In this study, we quantitatively evaluate chorus-driven electron acceleration during the 17 March 2013 storm, when Van Allen Probes observed very rapid electron acceleration up to multi MeV within ∼15 hours. A clear peak in electron phase space density observed at L∗ ∼ 4 indicates that the internal local acceleration process was operating. We construct the global distribution of chorus wave intensity from the low-altitude electron measurements by multiple POES satellites over a broad L-MLT region, which is used to simulate the radiation belt electron dynamics driven by chorus waves. Our. . .
Date: 08/2014 Publisher: IEEE DOI: 10.1109/URSIGASS.2014.6929882 Available at: http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6929882
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Authors: Butler Michael, and Laughery Sean
Title: The RBSP Spacecraft Power System Design and Development
Abstract: The RBSP (Radiation Belt Storm Probes) twin spacecraft are set to launch in August 2012. The spacecraft will be inserted into the highly elliptical regions of high energy particles trapped by the magnetic field of the earth. These regions are often referred to as the Van Allen Belts. The twin spacecraft will operate entirely within the radiation belts throughout their mission. Because of the intense environment of operation and to reduce cost and risk, the approach taken in the power system electronics was to use quasi conventional design, materials, and fabrication techniques encased in a 350mil thick aluminum enclosure. The spacecraft are spin stabilized with an axial boom that creates a shadow across the solar arrays. The power system topology selected was a 28V unregulat. . .
Date: 08/2012 Publisher: American Institute of Aeronautics and Astronautics DOI: 10.2514/MIECEC1210.2514/6.2012-4059 Available at: http://arc.aiaa.org/doi/pdf/10.2514/6.2012-4059
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Journal Article
Authors: Li Zhao, Hudson Mary, Kress Brian, and Paral Jan
Title: 3D test-particle simulation of the 17-18 March, 2013 CME-shock driven storm
Abstract: D test-particle simulation of energetic electrons (hundreds of keV to MeV), including both an initially trapped population and continuously injected population, driven by the Lyon-Fedder-Mobarry (LFM) global MHD model coupled with Magnetosphere-Ionosphere Coupler/Solver (MIX) boundary conditions, is performed for the March 17, 2013 storm. The electron trajectories are calculated and weighted using the ESA model for electron flux vs. energy and L. The simulation captures the flux dropout at both GOES-13 and GOES-15 locations after a strong CME-shock arrival which produced a Dst=−132 nT storm, and recovery to the pre-storm value later, consistent with GOES satellite measurements. This study provides the first 3D test-particle simulation combining the trapped and injected populations. The r. . .
Date: 06/2015 Publisher: Geophysical Research Letters DOI: 10.1002/2015GL064627 Available at: http://doi.wiley.com/10.1002/2015GL064627
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Authors: Artemyev A.V., Liu J., Angelopoulos V, and Runov A.
Title: Acceleration of ions by electric field pulses in the inner magnetosphere
Abstract: Intense (~5-15 mV/m), short-lived (≤1 min) electric field pulses have been observed to accompany earthward-propagating, dipolarizing flux bundles (DFB; flux tubes with a strong magnetic field) before they are stopped by the strong dipole field. Using Time History of Events and Macroscale Interactions During Substorms (THEMIS) observations and test particle modeling, we investigate particle acceleration around L-shell ~7-9 in the nightside magnetosphere and demonstrate that such pulses can effectively accelerate ions with tens of keV initial energy to hundreds of keV. This acceleration occurs because the ion gyroradius is comparable to the spatial scale of the localized electric field pulse at the leading edge of the flux bundle before it stops. The proposed acceleration mechanism can rep. . .
Date: 05/2015 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2015JA021160 Available at: http://doi.wiley.com/10.1002/2015JA021160
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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: Zhao H., Baker D N, Li X, Jaynes A. N., and Kanekal S G
Title: The Acceleration of Ultrarelativistic Electrons During a Small to Moderate Storm of 21 April 2017
Abstract: The ultrarelativistic electrons (E > ~3 MeV) in the outer radiation belt received limited attention in the past due to sparse measurements. Nowadays, the Van Allen Probes measurements of ultrarelativistic electrons with high energy resolution provide an unprecedented opportunity to study the dynamics of this population. In this study, using data from the Van Allen Probes, we report significant flux enhancements of ultrarelativistic electrons with energies up to 7.7 MeV during a small to moderate geomagnetic storm. The underlying physical mechanisms are investigated by analyzing and simulating the evolution of electron phase space density. The results suggest that during this storm, the acceleration mechanism for ultrarelativistic electrons in the outer belt is energy‐dependent: local acc. . .
Date: 06/2018 Publisher: Geophysical Research Letters DOI: 10.1029/2018GL078582 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL078582
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Authors: Ginet G P, ’Brien T P, Huston S L, Johnston W R, Guild T B, et al.
Title: AE9, AP9 and SPM: New Models for Specifying the Trapped Energetic Particle and Space Plasma Environment
Abstract: The radiation belts and plasma in the Earth’s magnetosphere pose hazards to satellite systems which restrict design and orbit options with a resultant impact on mission performance and cost. For decades the standard space environment specification used for spacecraft design has been provided by the NASA AE8 and AP8 trapped radiation belt models. There are well-known limitations on their performance, however, and the need for a new trapped radiation and plasma model has been recognized by the engineering community for some time. To address this challenge a new set of models, denoted AE9/AP9/SPM, for energetic electrons, energetic protons and space plasma has been developed. The new models offer significant improvements including more detailed spatial resolution and the quantification of u. . .
Date: 11/2013 Publisher: Space Science Reviews DOI: 10.1007/s11214-013-9964-y Available at: http://link.springer.com/article/10.1007%2Fs11214-013-9964-y
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Authors: Lyubchich A. A., Demekhov A. G., Titova E. E., and Yahnin A. G.
Title: Amplitude–frequency characteristics of ion–cyclotron and whistler-mode waves from Van Allen Probes data
Abstract: Using two-hour (from 2300 UT January 25, 2013 to 0100 UT January 26, 2013) measurement data from Van Allen Probes on fluxes of energetic particles, cold plasma density, and magnetic field magnitude, we have calculated the local growth rate of electromagnetic ion–cyclotron and whistler-mode waves for field-aligned propagation. The results of these calculations have been compared with wave spectra observed by the same Van Allen Probe spacecraft. The time intervals when the calculated wave increments are sufficiently large, and the frequency ranges corresponding to the enhancement peak agree with the frequency–time characteristics of observed electromagnetic waves. We have analyzed the influence of variations in the density and ionic composition of cold plasma, fluxes of energetic particl. . .
Date: 02/2017 Publisher: Geomagnetism and Aeronomy DOI: 10.1134/S001679321701008X Available at: https://link.springer.com/article/10.1134/S001679321701008X
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Authors: de Soria-Santacruz M., Li W, Thorne R M, Ma Q, Bortnik J, et al.
Title: Analysis of plasmaspheric hiss wave amplitudes inferred from low-altitude POES electron data: Validation with conjunctive Van Allen Probes observations
Abstract: Plasmaspheric hiss plays an important role in controlling the overall structure and dynamics of the Earth's radiation belts. The interaction of plasmaspheric hiss with radiation belt electrons is commonly evaluated using diffusion codes, which rely on statistical models of wave observations that may not accurately reproduce the instantaneous global wave distribution, or the limited in-situ satellite wave measurements from satellites. This paper evaluates the performance and limitations of a novel technique capable of inferring wave amplitudes from low-altitude electron flux observations from the POES spacecraft, which provide extensive coverage in L-shell and MLT. We found that, within its limitations, this technique could potentially be used to build a dynamic global model of the plasmasp. . .
Date: 10/2015 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2015JA021148 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2015JA021148/abstract
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Authors: de Soria-Santacruz M., Li W, Thorne R M, Ma Q, Bortnik J, et al.
Title: Analysis of plasmaspheric hiss wave amplitudes inferred from low-altitude POES electron data: Technique sensitivity analysis
Abstract: A novel technique capable of inferring wave amplitudes from low-altitude electron measurements from the POES spacecraft has been previously proposed to construct a global dynamic model of chorus and plasmaspheric hiss waves. In this paper we focus on plasmaspheric hiss, which is an incoherent broadband emission that plays a dominant role in the loss of energetic electrons from the inner magnetosphere. We analyze the sensitivity of the POES technique to different inputs used to infer the hiss wave amplitudes during three conjunction events with the Van Allen Probes. These amplitudes are calculated with different input models of the plasma density, wave frequency spectrum, and electron energy spectrum, and the results are compared to the wave observations from the twin Van Allen Probes. Only. . .
Date: 04/2015 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2014JA020941 Available at: http://doi.wiley.com/10.1002/2014JA020941
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Authors: Mourenas D., Artemyev A. V., Agapitov O.V., Krasnoselskikh V., and Li W
Title: Approximate analytical solutions for the trapped electron distribution due to quasi-linear diffusion by whistler-mode waves
Abstract: The distribution of trapped energetic electrons inside the Earth's radiation belts is the focus of intense studies aiming at better describing the evolution of the space environment in the presence of various disturbances induced by the solar wind or by an enhanced lightning activity. Such studies are usually performed by means of comparisons with full numerical simulations solving the Fokker-Planck quasi-linear diffusion equation for the particle distribution function. Here, we present for the first time approximate but realistic analytical solutions for the electron distribution, which are shown to be in good agreement with exact numerical solutions in situations where resonant scattering of energetic electrons by whistler-mode hiss, lightning-generated or chorus waves, is the dominant p. . .
Date: 11/2014 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2014JA020443 Available at: http://doi.wiley.com/10.1002/2014JA020443
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Authors: Lyons L R, Nishimura Y., Gallardo-Lacourt B., Nicolls M. J., Chen S., et al.
Title: Azimuthal flow bursts in the Inner Plasma Sheet and Possible Connection with SAPS and Plasma Sheet Earthward Flow Bursts
Abstract: We have combined radar observations and auroral images obtained during the PFISR Ion Neutral Observations in the Thermosphere campaign to show the common occurrence of westward moving, localized auroral brightenings near the auroral equatorward boundary and to show their association with azimuthally moving flow bursts near or within the SAPS region. These results indicate that the SAPS region, rather than consisting of relatively stable proton precipitation and westward flows, can have rapidly varying flows, with speeds varying from ~100 m/s to ~1 km/s in just a few minutes. The auroral brightenings are associated with bursts of weak electron precipitation that move westward with the westward flow bursts and extend into the SAPS region. Additionally, our observations show evidence that the. . .
Date: 05/2015 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2015JA021023 Available at: http://doi.wiley.com/10.1002/2015JA021023
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Authors: Kistler L.M., Mouikis C. G., Spence H.E., Menz A.M., Skoug R.M., et al.
Title: The Source of O + in the Storm-time Ring Current
Abstract: A stretched and compressed geomagnetic field occurred during the main phase of a geomagnetic storm on 1 June 2013. During the storm the Van Allen Probes spacecraft made measurements of the plasma sheet boundary layer, and observed large fluxes of O+ ions streaming up the field line from the nightside auroral region. Prior to the storm main phase there was an increase in the hot (>1 keV) and more isotropic O+ions in the plasma sheet. In the spacecraft inbound pass through the ring current region during the storm main phase, the H+ and O+ ions were significantly enhanced. We show that this enhanced inner magnetosphere ring current population is due to the inward adiabatic convection of the plasma sheet ion population. The energy range of the O+ ion plasma sheet that impacts the ring curren. . .
Date: 05/2016 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2015JA022204 Available at: http://doi.wiley.com/10.1002/2015JA022204
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Authors: Kistler L.M., Mouikis C. G., Spence H.E., Menz A.M., Skoug R.M., et al.
Title: The Source of O + in the Storm-time Ring Current
Abstract: A stretched and compressed geomagnetic field occurred during the main phase of a geomagnetic storm on 1 June 2013. During the storm the Van Allen Probes spacecraft made measurements of the plasma sheet boundary layer, and observed large fluxes of O+ ions streaming up the field line from the nightside auroral region. Prior to the storm main phase there was an increase in the hot (>1 keV) and more isotropic O+ions in the plasma sheet. In the spacecraft inbound pass through the ring current region during the storm main phase, the H+ and O+ ions were significantly enhanced. We show that this enhanced inner magnetosphere ring current population is due to the inward adiabatic convection of the plasma sheet ion population. The energy range of the O+ ion plasma sheet that impacts the ring curren. . .
Date: 05/2016 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2015JA022204 Available at: http://doi.wiley.com/10.1002/2015JA022204
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Authors: Claudepierre S G, O'Brien T P, Blake J B, Fennell J. F., Roeder J. L., et al.
Title: A background correction algorithm for Van Allen Probes MagEIS electron flux measurements
Abstract: We describe an automated computer algorithm designed to remove background contamination from the Van Allen Probes MagEIS electron flux measurements. We provide a detailed description of the algorithm with illustrative examples from on-orbit data. We find two primary sources of background contamination in the MagEIS electron data: inner zone protons and bremsstrahlung X-rays generated by energetic electrons interacting with the spacecraft material. Bremsstrahlung X-rays primarily produce contamination in the lower energy MagEIS electron channels (~30-500 keV) and in regions of geospace where multi-MeV electrons are present. Inner zone protons produce contamination in all MagEIS energy channels at roughly L < 2.5. The background corrected MagEIS electron data produce a more accurate me. . .
Date: 06/2015 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2015JA021171 Available at: http://doi.wiley.com/10.1002/2015JA021171
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Authors: Claudepierre S G, O'Brien T P, Blake J B, Fennell J. F., Roeder J. L., et al.
Title: A background correction algorithm for Van Allen Probes MagEIS electron flux measurements
Abstract: We describe an automated computer algorithm designed to remove background contamination from the Van Allen Probes MagEIS electron flux measurements. We provide a detailed description of the algorithm with illustrative examples from on-orbit data. We find two primary sources of background contamination in the MagEIS electron data: inner zone protons and bremsstrahlung X-rays generated by energetic electrons interacting with the spacecraft material. Bremsstrahlung X-rays primarily produce contamination in the lower energy MagEIS electron channels (~30-500 keV) and in regions of geospace where multi-MeV electrons are present. Inner zone protons produce contamination in all MagEIS energy channels at roughly L < 2.5. The background corrected MagEIS electron data produce a more accurate me. . .
Date: 06/2015 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2015JA021171 Available at: http://doi.wiley.com/10.1002/2015JA021171
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Authors: Millan R M, McCarthy M P, Sample J G, Smith D M, Thompson L D, et al.
Title: The Balloon Array for RBSP Relativistic Electron Losses (BARREL)
Abstract: BARREL is a multiple-balloon investigation designed to study electron losses from Earth’s Radiation Belts. Selected as a NASA Living with a Star Mission of Opportunity, BARREL augments the Radiation Belt Storm Probes mission by providing measurements of relativistic electron precipitation with a pair of Antarctic balloon campaigns that will be conducted during the Austral summers (January-February) of 2013 and 2014. During each campaign, a total of 20 small (∼20 kg) stratospheric balloons will be successively launched to maintain an array of ∼5 payloads spread across ∼6 hours of magnetic local time in the region that magnetically maps to the radiation belts. Each balloon carries an X-ray spectrometer to measure the bremsstrahlung X-rays produced by precipitating relativistic electr. . .
Date: 11/2013 Publisher: Space Science Reviews DOI: 10.1007/s11214-013-9971-z Available at: http://link.springer.com/article/10.1007%2Fs11214-013-9971-z
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Authors: Millan R M, McCarthy M P, Sample J G, Smith D M, Thompson L D, et al.
Title: The Balloon Array for RBSP Relativistic Electron Losses (BARREL)
Abstract: BARREL is a multiple-balloon investigation designed to study electron losses from Earth’s Radiation Belts. Selected as a NASA Living with a Star Mission of Opportunity, BARREL augments the Radiation Belt Storm Probes mission by providing measurements of relativistic electron precipitation with a pair of Antarctic balloon campaigns that will be conducted during the Austral summers (January-February) of 2013 and 2014. During each campaign, a total of 20 small (∼20 kg) stratospheric balloons will be successively launched to maintain an array of ∼5 payloads spread across ∼6 hours of magnetic local time in the region that magnetically maps to the radiation belts. Each balloon carries an X-ray spectrometer to measure the bremsstrahlung X-rays produced by precipitating relativistic electr. . .
Date: 11/2013 Publisher: Space Science Reviews DOI: 10.1007/s11214-013-9971-z Available at: http://link.springer.com/article/10.1007%2Fs11214-013-9971-z
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Authors: Jin YuYue, Yang Chang, He Yihua, Liu Si, Zhou Qinghua, et al.
Title: Butterfly distribution of Earth’s radiation belt relativistic electrons induced by dayside chorus
Abstract: Previous theoretical studies have shown that dayside chorus can produce butterfly distribution of energetic electrons in the Earth’s radiation belts by preferentially accelerating medium pitch angle electrons, but this requires the further confirmation from high-resolution satellite observation. Here, we report correlated Van Allen Probes data on wave and particle during the 11–13 April, 2014 geomagnetic storm. We find that a butterfly pitch angle distribution of relativistic electrons is formed around the location L = 4.52, corresponding to the presence of enhanced dayside chorus. Using a Gaussian distribution fit to the observed chorus spectra, we calculate the bounce-averaged diffusion rates and solve two-dimensional Fokker-Planck equation. Numerical results demonstrate that acceler. . .
Date: 09/2017 Publisher: Science China Technological Sciences DOI: 10.1007/s11431-017-9067-y Available at: https://link.springer.com/article/10.1007/s11431-017-9067-y
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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: Turner D. L., Angelopoulos V, Morley S. K., Henderson M G, Reeves G D, et al.
Title: On the cause and extent of outer radiation belt losses during the 30 September 2012 dropout event
Abstract: On 30 September 2012, a flux “dropout” occurred throughout Earth's outer electron radiation belt during the main phase of a strong geomagnetic storm. Using eight spacecraft from NASA's Time History of Events and Macroscale Interactions during Substorms (THEMIS) and Van Allen Probes missions and NOAA's Geostationary Operational Environmental Satellites constellation, we examined the full extent and timescales of the dropout based on particle energy, equatorial pitch angle, radial distance, and species. We calculated phase space densities of relativistic electrons, in adiabatic invariant coordinates, which revealed that loss processes during the dropout were > 90% effective throughout the majority of the outer belt and the plasmapause played a key role in limiting the spatial extent . . .
Date: 03/2014 Publisher: Journal of Geophysical Research: Space Physics Pages: 1530 - 1540 DOI: 10.1002/2013JA019446 Available at: http://doi.wiley.com/10.1002/2013JA019446
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Authors: Lee Jeongwoo, Min Kyungguk, and Kim Kap-Sung
Title: Characteristic dimension of electromagnetic ion cyclotron wave activity in the magnetosphere
Abstract: [1] In this paper, we estimate the size of coherent activity of electromagnetic ion cyclotron (EMIC) waves using the multi‒spacecraft observations made during the Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission. We calculate the cross‒correlations between EMIC wave powers measured by different THEMIS spacecraft, plot them over the separation distances between pairs of observing spacecraft, and determine the 1/e folding distance of the correlations as the characteristic dimension of the coherent wave activity. The characteristic radius in the direction transverse to the local magnetic field is found to lie in rather a wide range of 1500–8600 km varying from the AM to PM sectors and also from hydrogen to helium bands. However, the characteristic d. . .
Date: 04/2013 Publisher: Journal of Geophysical Research: Space Physics Pages: 1651 - 1658 DOI: 10.1002/jgra.50242 Available at: http://doi.wiley.com/10.1002/jgra.50242
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Authors: Ma Q, Li W, Thorne R M, Bortnik J, Reeves G D, et al.
Title: Characteristic energy range of electron scattering due to plasmaspheric hiss
Abstract: We investigate the characteristic energy range of electron flux decay due to the interaction with plasmaspheric hiss in the Earth's inner magnetosphere. The Van Allen Probes have measured the energetic electron flux decay profiles in the Earth's outer radiation belt during a quiet period following the geomagnetic storm that occurred on 7 November 2015. The observed energy of significant electron decay increases with decreasing L shell and is well correlated with the energy band corresponding to the first adiabatic invariant μ = 4–200 MeV/G. The electron diffusion coefficients due to hiss scattering are calculated at L = 2–6, and the modeled energy band of effective pitch angle scattering is also well correlated with the constant μ lines and is consistent with the observed e. . .
Date: 11/2016 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023311 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA023311/full
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Authors: Yue Chao, Bortnik Jacob, Thorne Richard M, Ma Qianli, An Xin, et al.
Title: The characteristic pitch angle distributions of 1 eV to 600 keV protons near the equator based on Van Allen Probes observations
Abstract: Understanding the source and loss processes of various plasma populations is greatly aided by having accurate knowledge of their pitch angle distributions (PADs). Here, we statistically analyze ~1 eV to 600 keV hydrogen (H+) PADs near the geomagnetic equator in the inner magnetosphere based on Van Allen Probes measurements, to comprehensively investigate how the H+ PADs vary with different energies, magnetic local times (MLTs), L-shells, and geomagnetic conditions. Our survey clearly indicates four distinct populations with different PADs: (1) a pancake distribution of the plasmaspheric H+ at low L-shells except for dawn sector; (2) a bi-directional field-aligned distribution of the warm plasma cloak; (3) pancake or isotropic distributions of ring current H+; (4) radiation belt particles s. . .
Date: 08/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024421 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA024421/full
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Authors: Yue Chao, Chen Lunjin, Bortnik Jacob, Ma Qianli, Thorne Richard M, et al.
Title: The characteristic response of whistler mode waves to interplanetary shocks
Abstract: Magnetospheric whistler mode waves play a key role in regulating the dynamics of the electron radiation belts. Recent satellite observations indicate a significant influence of interplanetary (IP) shocks on whistler mode wave power in the inner magnetosphere. In this study, we statistically investigate the response of whistler mode chorus and plasmaspheric hiss to IP shocks based on Van Allen Probes and THEMIS satellite observations. Immediately after the IP shock arrival, chorus wave power is usually intensified, often at post-midnight to pre-noon sector, while plasmaspheric hiss wave power predominantly decreases near the dayside but intensifies near the nightside. We conclude that chorus wave intensification outside the plasmasphere is probably associated with the suprathermal electron . . .
Date: 09/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024574 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA024574/full
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Authors: Pinto Víctor A., Bortnik Jacob, Moya Pablo S., Lyons Larry R., Sibeck David G., et al.
Title: Characteristics, Occurrence and Decay Rates of Remnant Belts associated with Three-Belt events in the Earth's Radiation Belts
Abstract: Shortly after the launch of the Van Allen Probes, a new three‐belt configuration of the electron radiation belts was reported. Using data between September 2012 and November 2017, we have identified 30 three‐belt events and found that about 18% of geomagnetic storms result in such configuration. Based on the identified events, we evaluated some characteristics of the remnant (intermediate) belt. We determined the energy range of occurrence and found it peaks at E = 5.2 MeV. We also determined that the magnetopause location and SYM‐H value may play an important role in the outer belt losses that lead to formation and location of the remnant belt. Finally, we calculated the decay rates of the remnant belt for all events and found that their lifetime gets longer as energy increases,. . .
Date: 10/2018 Publisher: Geophysical Research Letters DOI: 10.1029/2018GL080274 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL080274
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Authors: Xu Jiyao, He Zhaohai, Baker D.N., Roth Ilan, Wang C., et al.
Title: Characteristics of high energy proton responses to geomagnetic activities in the inner radiation belt observed by the RBSP satellite
Abstract: High energy trapped particles in the radiation belts constitute potential threats to the functionality of satellites as they enter into those regions. In the inner radiation belt, the characteristics of high‐energy (>20MeV) protons variations during geomagnetic activity times have been studied by implementing four‐year (2013‐2016) observations of the Van Allen probes. An empirical formula has been used to remove the satellite orbit effect, by which proton fluxes have been normalized to the geomagnetic equator. Case studies show that the region of L<1.7 is relatively stable, while L>1.7 is more dynamic and the most significant variation of proton fluxes occurs at L=2.0. The four‐year survey at L=2.0 indicates that for every geomagnetic storm, sharp descent in proton fluxes is accomp. . .
Date: 05/2019 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2018JA026205 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JA026205
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Authors: Zhao H., Li X, Blake J B, Fennell J. F., Claudepierre S G, et al.
Title: Characteristics of pitch angle distributions of 100 s keV electrons in the slot region and inner radiation belt
Abstract: The pitch angle distribution (PAD) of energetic electrons in the slot region and inner radiation belt received little attention in the past decades due to the lack of quality measurements. Using the state-of-art pitch-angle-resolved data from the Magnetic Electron Ion Spectrometer (MagEIS) instrument onboard the Van Allen Probes, a detailed analysis of 100 s keV electron PADs below L = 4 is performed, in which the PADs is categorized into three types: normal (flux peaking at 90∘), cap (exceedingly peaking narrowly around 90∘) and 90∘-minimum (lower flux at 90∘) PADs. By examining the characteristics of the PADs of ~460 keV electrons for over a year, we find that the 90∘-minimum PADs are generally present in the inner belt (L < 2), while normal PADs dominate at .L ~3.5. . .
Date: 11/2014 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2014JA020386 Available at: http://doi.wiley.com/10.1002/2014JA020386
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Authors: Zhao H., Johnston W.R., Baker D.N., Li X, Ni B, et al.
Title: Characterization and Evolution of Radiation Belt Electron Energy Spectra Based on the Van Allen Probes Measurements
Abstract: Based on the measurements of ~100‐keV to 10‐MeV electrons from the Magnetic Electron Ion Spectrometer (MagEIS) and Relativistic Electron and Proton Telescope (REPT) on the Van Allen Probes, the radiation belt electron energy spectra characterization and evolution have been investigated systematically. The results show that the majority of radiation belt electron energy spectra can be represented by one of three types of distributions: exponential, power law, and bump‐on‐tail (BOT). The exponential spectra are generally dominant in the outer radiation belt outside the plasmasphere, power law spectra usually appear at high L‐shells during injections of lower‐energy electrons, and BOT spectra commonly dominate inside the plasmasphere at L>2.5 during relatively quiet times. The. . .
Date: 05/2019 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2019JA026697 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019JA026697
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Authors: Min Kyungguk, Lee Jeongwoo, and Keika Kunihiro
Title: Chorus wave generation near the dawnside magnetopause due to drift shell splitting of substorm-injected electrons
Abstract: We study the relationship between the electron injection and the chorus waves during a substorm event on 23 March 2007. The chorus waves were detected at high geomagnetic latitude (∼70°S) Antarctic observatories in the range of 0600–0900 h in magnetic local time (MLT). Electrons drifting from the injection event were measured by two LANL spacecraft at 0300 and 0900 MLT. The mapping of auroral brightening areas to the magnetic equator shows that the injection occurred in an MLT range of 2200–2400. This estimate is consistent with observations by the THEMIS A, B, and D spacecraft (which were located at 2100 MLT and did not observe electron injections). Our backward model tracing from the magnetic equator near the dawnside magnetopause (which magnetically connects to the Antar. . .
Date: 10/2010 Publisher: American Geophysical Union DOI: 10.1029/2010JA015474
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Authors: Li Jinxing, Bortnik Jacob, An Xin, Li Wen, Thorne Richard M, et al.
Title: Chorus Wave Modulation of Langmuir Waves in the Radiation Belts
Abstract: Using high-resolution waveforms measured by the Van Allen Probes, we report a novel observation in the radiation belts. Namely, we show that multiband, discrete, rising-tone whistler mode chorus emissions exhibit a one-to-one correlation with Langmuir wave bursts. Moreover, the periodic Langmuir wave bursts are generally observed at the phase location where the chorus wave E|| component is oriented opposite to its propagation direction. The electron measurements show a beam in phase space density at the particle velocity that matches the parallel phase velocity of the chorus waves. Based on this evidence, we conclude that the chorus waves accelerate the suprathermal electrons via Landau resonance and generate a localized electron beam in phase space density. Consequently, the Langmuir wave. . .
Date: 12/2017 Publisher: Geophysical Research Letters Pages: 11,713 - 11,721 DOI: 10.1002/2017GL075877 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017GL075877/full
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Authors: Li Jinxing, Bortnik Jacob, An Xin, Li Wen, Thorne Richard M, et al.
Title: Chorus Wave Modulation of Langmuir Waves in the Radiation Belts
Abstract: Using high-resolution waveforms measured by the Van Allen Probes, we report a novel observation in the radiation belts. Namely, we show that multiband, discrete, rising-tone whistler mode chorus emissions exhibit a one-to-one correlation with Langmuir wave bursts. Moreover, the periodic Langmuir wave bursts are generally observed at the phase location where the chorus wave E|| component is oriented opposite to its propagation direction. The electron measurements show a beam in phase space density at the particle velocity that matches the parallel phase velocity of the chorus waves. Based on this evidence, we conclude that the chorus waves accelerate the suprathermal electrons via Landau resonance and generate a localized electron beam in phase space density. Consequently, the Langmuir wave. . .
Date: 12/2017 Publisher: Geophysical Research Letters Pages: 11,713 - 11,721 DOI: 10.1002/2017GL075877 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017GL075877/full
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Authors: Cohen Ross, Gerrard Andrew, Lanzerotti Louis, Soto-Chavez A. R., Kim Hyomin, et al.
Title: Climatology of high β plasma measurements in Earth's inner magnetosphere
Abstract: Since their launch in August 2012, the Radiation Belt Storm Probe Ion Composition Experiment (RBSPICE) instruments on the NASA Van Allen Probes spacecraft have been making continuous high resolution measurements of Earth's ring current plasma environment. After a full traversal through all magnetic local times, a climatology (i.e., a survey of observations) of high beta (β) plasma events (defined here as β>1) as measured by the RBSPICE instrument in the ∼45-keV to ∼600-keV proton energy range in the inner magnetosphere (L<5.8) has been constructed. In this paper we report this climatology of such high β plasma occurrences, durations, and their general characteristics. Specifically, we show that most high β events in the RBSPICE energy range are associated with post-dusk/pre-midnigh. . .
Date: 12/2016 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA022513 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA022513/full
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Authors: Cohen Ross, Gerrard Andrew J., Lanzerotti Louis J., Soto-Chavez A. R., Kim Hyomin, et al.
Title: Climatology of high-β plasma measurements in Earth's inner magnetosphere
Abstract: Since their launch in August 2012, the Radiation Belt Storm Probe Ion Composition Experiment (RBSPICE) instruments on the NASA Van Allen Probes spacecraft have been making continuous high-resolution measurements of Earth's ring current plasma environment. After a full traversal through all magnetic local times, a climatology (i.e., a survey of observations) of high-beta (β) plasma events (defined here as β > 1) as measured by the RBSPICE instrument in the ∼45 keV to ∼600 keV proton energy range in the inner magnetosphere (L < 5.8) has been constructed. In this paper we report this climatology of such high-β plasma occurrences, durations, and their general characteristics. Specifically, we show that most high-β events in the RBSPICE energy range are associated with postdusk/premidni. . .
Date: 01/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA022513 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA022513
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Authors: Li Jinxing, Bortnik Jacob, Li Wen, Thorne Richard M., Ma Qianli, et al.
Title: Coherently modulated whistler mode waves simultaneously observed over unexpectedly large spatial scales
Abstract: Utilizing simultaneous twin Van Allen Probes observations of whistler mode waves at variable separations, we are able to distinguish the temporal variations from spatial variations, determine the coherence spatial scale, and suggest the possible mechanism of wave modulation. The two probes observed coherently modulated whistler mode waves simultaneously at an unexpectedly large distance up to ~4.3 RE over 3 h during a relatively quiet period. The modulation of 150–500 Hz plasmaspheric hiss was correlated with whistler mode waves measured outside the plasmasphere across 3 h in magnetic local time and 3 L shells, revealing that the modulation was temporal in nature. We suggest that the coherent modulation of whistler mode waves was associated with the coherent ULF waves measured ov. . .
Date: 02/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023706 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA023706/full
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Authors: Li Jinxing, Bortnik Jacob, Li Wen, Thorne Richard M, Ma Qianli, et al.
Title: Coherently modulated whistler mode waves simultaneously observed over unexpectedly large spatial scales
Abstract: Utilizing simultaneous twin Van Allen Probes observations of whistler mode waves at variable separations, we are able to distinguish the temporal variations from spatial variations, determine the coherence spatial scale, and suggest the possible mechanism of wave modulation. The two probes observed coherently modulated whistler mode waves simultaneously at an unexpectedly large distance up to ~4.3 RE over 3 h during a relatively quiet period. The modulation of 150–500 Hz plasmaspheric hiss was correlated with whistler mode waves measured outside the plasmasphere across 3 h in magnetic local time and 3 L shells, revealing that the modulation was temporal in nature. We suggest that the coherent modulation of whistler mode waves was associated with the coherent ULF waves measured ov. . .
Date: 02/2017 Publisher: Journal of Geophysical Research: Space Physics Pages: 1871-1882 DOI: 10.1002/2016JA023706 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA023706/full
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Authors: Li Jinxing, Bortnik Jacob, Li Wen, Thorne Richard M., Ma Qianli, et al.
Title: Coherently modulated whistler mode waves simultaneously observed over unexpectedly large spatial scales
Abstract: Utilizing simultaneous twin Van Allen Probes observations of whistler mode waves at variable separations, we are able to distinguish the temporal variations from spatial variations, determine the coherence spatial scale, and suggest the possible mechanism of wave modulation. The two probes observed coherently modulated whistler mode waves simultaneously at an unexpectedly large distance up to ~4.3 RE over 3 h during a relatively quiet period. The modulation of 150–500 Hz plasmaspheric hiss was correlated with whistler mode waves measured outside the plasmasphere across 3 h in magnetic local time and 3 L shells, revealing that the modulation was temporal in nature. We suggest that the coherent modulation of whistler mode waves was associated with the coherent ULF waves measured ov. . .
Date: 02/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023706 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA023706/full
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Authors: Li Jinxing, Bortnik Jacob, Li Wen, Thorne Richard M, Ma Qianli, et al.
Title: Coherently modulated whistler mode waves simultaneously observed over unexpectedly large spatial scales
Abstract: Utilizing simultaneous twin Van Allen Probes observations of whistler mode waves at variable separations, we are able to distinguish the temporal variations from spatial variations, determine the coherence spatial scale, and suggest the possible mechanism of wave modulation. The two probes observed coherently modulated whistler mode waves simultaneously at an unexpectedly large distance up to ~4.3 RE over 3 h during a relatively quiet period. The modulation of 150–500 Hz plasmaspheric hiss was correlated with whistler mode waves measured outside the plasmasphere across 3 h in magnetic local time and 3 L shells, revealing that the modulation was temporal in nature. We suggest that the coherent modulation of whistler mode waves was associated with the coherent ULF waves measured ov. . .
Date: 02/2017 Publisher: Journal of Geophysical Research: Space Physics Pages: 1871-1882 DOI: 10.1002/2016JA023706 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA023706/full
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Authors: Katsavrias C., Daglis I. A., Li W, Dimitrakoudis S., Georgiou M., et al.
Title: Combined effects of concurrent Pc5 and chorus waves on relativistic electron dynamics
Abstract: We present electron phase space density (PSD) calculations as well as concurrent Pc5 and chorus wave activity observations during two intense geomagnetic storms caused by interplanetary coronal mass ejections (ICMEs) resulting in contradicting net effect. We show that, during the 17 March 2013 storm, the coincident observation of chorus and relativistic electron enhancements suggests that the prolonged chorus wave activity seems to be responsible for the enhancement of the electron population in the outer radiation belt even in the presence of pronounced outward diffusion. On the other hand, the significant depletion of electrons, during the 12 September 2014 storm, coincides with long-lasting outward diffusion driven by the continuous enhanced Pc5 activity since chorus wave a. . .
Date: 09/2015 Publisher: Annales Geophysicae Pages: 1173 - 1181 DOI: 10.5194/angeo-33-1173-2015 Available at: http://www.ann-geophys.net/33/1173/2015/
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Authors: Hua Man, Ni Binbin, Fu Song, Gu Xudong, Xiang Zheng, et al.
Title: Combined Scattering of Outer Radiation Belt Electrons by Simultaneously Occurring Chorus, Exohiss, and Magnetosonic Waves
Abstract: We report a typical event that fast magnetosonic (MS) waves, exohiss, and two‐band chorus waves occurred simultaneously on the dayside observed by Van Allen Probes on 25 December 2013. By combining calculations of electron diffusion coefficients and 2‐D Fokker‐Planck diffusion simulations, we quantitatively analyze the combined scattering effect of multiple waves to demonstrate that the net impact of combined scattering does not simply depend on the wave intensity dominance of various plasma waves. Although the observed MS waves are most intense, the electron butterfly distribution is inhibited by exohiss and chorus, and electrons are considerably accelerated by combined scattering of MS and chorus waves. The simulated electron pitch angle distributions exhibit the variation trend co. . .
Date: 09/2018 Publisher: Geophysical Research Letters DOI: 10.1029/2018GL079533 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL079533
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Authors: Saikin A.A., Jordanova V.K., Zhang J.C., Smith C.W., Spence H.E., et al.
Title: Comparing simulated and observed EMIC wave amplitudes using in situ Van Allen Probes’ measurements
Abstract: We perform a statistical study calculating electromagnetic ion cyclotron (EMIC) wave amplitudes based off in situ plasma measurements taken by the Van Allen Probes’ (1.1–5.8 Re) Helium, Oxygen, Proton, Electron (HOPE) instrument. Calculated wave amplitudes are compared to EMIC waves observed by the Electric and Magnetic Field Instrument Suite and Integrated Science on board the Van Allen Probes during the same period. The survey covers a 22-month period (1 November 2012 to 31 August 2014), a full Van Allen Probe magnetic local time (MLT) precession. The linear theory proxy was used to identify EMIC wave events with plasma conditions favorable for EMIC wave excitation. Two hundred and thirty-two EMIC wave events (103 H+-band and 129 He+-band) were selected for this comparison. Nearly . . .
Date: 02/2018 Publisher: Journal of Atmospheric and Solar-Terrestrial Physics DOI: 10.1016/j.jastp.2018.01.024 Available at: https://www.sciencedirect.com/science/article/pii/S1364682617302122
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Authors: Lui A. T. Y., Mitchell D G, and Lanzerotti L J
Title: Comparison of Energetic Electron Intensities Outside and Inside the Radiation Belts
Abstract: The intensities of energetic electrons (~25 – 800 keV) outside and inside Earth's radiation belts are reported using measurements from THEMIS and Van Allen Probes during non-geomagnetic storm periods. Three intervals of current disruption/dipolarization events in August, 2013 were selected for comparison. The following results are obtained. (1) Phase space densities (PSDs) for the equatorially mirroring electron population at three values of the first adiabatic invariant (20, 70, and 200 MeV/G) at the outer radiation belt boundary are found to be one to three orders of magnitude higher than values measured just inside the radiation belt. (2) There is indication that substorm activity leads to PSD increases inside L = 5.5 in less than 1 hr. (3) Evidence for progressive inward tr. . .
Date: 08/2014 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2014JA020049 Available at: http://doi.wiley.com/10.1002/2014JA020049
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Authors: Lui A. T. Y., Mitchell D G, and Lanzerotti L J
Title: Comparison of Energetic Electron Intensities Outside and Inside the Radiation Belts
Abstract: The intensities of energetic electrons (~25 – 800 keV) outside and inside Earth's radiation belts are reported using measurements from THEMIS and Van Allen Probes during non-geomagnetic storm periods. Three intervals of current disruption/dipolarization events in August, 2013 were selected for comparison. The following results are obtained. (1) Phase space densities (PSDs) for the equatorially mirroring electron population at three values of the first adiabatic invariant (20, 70, and 200 MeV/G) at the outer radiation belt boundary are found to be one to three orders of magnitude higher than values measured just inside the radiation belt. (2) There is indication that substorm activity leads to PSD increases inside L = 5.5 in less than 1 hr. (3) Evidence for progressive inward tr. . .
Date: 08/2014 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2014JA020049 Available at: http://doi.wiley.com/10.1002/2014JA020049
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Authors: Turner D. L., Angelopoulos V, Li W, Bortnik J, Ni B, et al.
Title: Competing source and loss mechanisms due to wave-particle interactions in Earth's outer radiation belt during the 30 September to 3 October 2012 geomagnetic storm
Abstract: Drastic variations of Earth's outer radiation belt electrons ultimately result from various competing source, loss, and transport processes, to which wave-particle interactions are critically important. Using 15 spacecraft including NASA's Van Allen Probes, THEMIS, and SAMPEX missions and NOAA's GOES and POES constellations, we investigated the evolution of the outer belt during the strong geomagnetic storm of 30 September to 3 October 2012. This storm's main phase dropout exhibited enhanced losses to the atmosphere at L* < 4, where the phase space density (PSD) of multi-MeV electrons dropped by over an order of magnitude in <4 h. Based on POES observations of precipitating >1 MeV electrons and energetic protons, SAMPEX >1 MeV electrons, and ground observations of band-limited Pc. . .
Date: 03/2014 Publisher: Journal of Geophysical Research: Space Physics Pages: 1960 - 1979 DOI: 10.1002/jgra.v119.310.1002/2014JA019770 Available at: http://doi.wiley.com/10.1002/jgra.v119.3http://doi.wiley.com/10.1002/2014JA019770
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