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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: Min Kyungguk, Boardsen Scott A., Denton Richard E, and Liu Kaijun
Title: Equatorial Evolution of the Fast Magnetosonic Mode in the Source Region: Observation-Simulation Comparison of the Preferential Propagation Direction
Abstract: Recent analysis of an event observed by the Van Allen Probes in the source region outside the plasmapause has shown that fast magnetosonic waves (also referred to as equatorial noise) propagate preferentially in the azimuthal direction, implying that wave amplification should occur during azimuthal propagation. To demonstrate this, we carry out 2‐D particle‐in‐cell simulations of the fast magnetosonic mode at the dipole magnetic equator with the simulation box size, the magnetic field inhomogeneity, and the plasma parameters chosen from the same event recently analyzed. The self‐consistently evolving electric and magnetic field fluctuations are characterized by spectral peaks at harmonics of the local proton cyclotron frequency. The azimuthal component of the electric field fluctua. . .
Date: 11/2018 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2018JA026037 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JA026037
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Authors: Min Kyungguk, Bortnik J, and Lee Jeongwoo
Title: A novel technique for rapid L∗ calculation: algorithm and implementation
Abstract: Computing the magnetic drift invariant, L*, rapidly and accurately has always been a challenge to magnetospheric modelers, especially given the im- portance of this quantity in the radiation belt community. Min et al. (2013) proposed a new method of calculating L* using the principle of energy con- servation. Continuing with the approach outlined therein, the present pa- per focuses on the technical details of the algorithm to outline the implemen- tation, systematic analysis of accuracy, and verification of the speed of the new method. We also show new improvements which enable near real-time computation of L*. The relative error is on the order of 10−3 when ∼ 0.1 RE grid resolution is used and the calculation speed is about two seconds per particle in the popular Tsyganenko. . .
Date: 05/2013 Publisher: Journal of Geophysical Research Pages: 1912-1921 DOI: 10.1002/jgra.50250 Available at: http://onlinelibrary.wiley.com/doi/10.1002/jgra.50250/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 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: Millan R.M.
Title: Understanding relativistic electron losses with BARREL
Abstract: The primary scientific objective of the Balloon Array for RBSP Relativistic Electron Losses (BARREL) is to understand the processes responsible for scattering relativistic electrons into Earth's atmosphere. BARREL is the first Living with a Star Geospace Mission of Opportunity, and will consist of two Antarctic balloon campaigns conducted in the 2012 and 2013 Austral summer seasons. During each campaign, a total of 20 small View the MathML source(∼20kg) balloon payloads will be launched, providing multi-point measurements of electron precipitation in conjunction with in situ measurements from the two RBSP spacecraft, scheduled to launch in May 2012. In this paper we outline the scientific objectives of BARREL, highlighting a few key science questions that will be addressed by BARREL in c. . .
Date: 07/2011 Publisher: Journal of Atmospheric and Solar-Terrestrial Physics Pages: 1425 - 1434 DOI: 10.1016/j.jastp.2011.01.006 Available at: http://www.sciencedirect.com/science/article/pii/S1364682611000071
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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: Meredith Nigel P, Horne Richard B, Kersten Tobias, Li Wen, Bortnik Jacob, et al.
Title: Global model of plasmaspheric hiss from multiple satellite observations
Abstract: We present a global model of plasmaspheric hiss, using data from eight satellites, extending the coverage and improving the statistics of existing models. We use geomagnetic activity dependent templates to separate plasmaspheric hiss from chorus. In the region 22‐14 MLT the boundary between plasmaspheric hiss and chorus moves to lower L∗ values with increasing geomagnetic activity. The average wave intensity of plasmaspheric hiss is largest on the dayside and increases with increasing geomagnetic activity from midnight through dawn to dusk. Plasmaspheric hiss is most intense and spatially extended in the 200‐500 Hz frequency band during active conditions, 400 Date: 05/2018 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2018JA025226 Available at: http://doi.wiley.com/10.1029/2018JA025226http://onlinelibrary.wiley.com/wol1/doi/10.1029/2018JA025226/fullpdfhttps://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1029%2F2018JA025226
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Authors: McGee Timothy G, Shankar Uday J, and Kemp Brian L
Title: Analysis of Spinning Spacecraft with Wire Booms Part 2: Out-of-Plane Dynamics and Maneuvers
Abstract: An analysis of the dynamics for a spin stabilized spacecraft consisting of a rigid central hub with four long exible wire booms is presented. The analysis focuses on the dynamics out of the spin plane of the spacecraft. Companion papers will focus on the derivations of the full nonlinear dynamics and analysis of the in plane dynamics. A linear analysis is used to estimate the mode shapes of the free response of the system, the e ects of various damping mechanisms on these modes, and the dynamic response of the system to various maneuvers. The results of an independent simulation of the full nonlinear dynamics of the system are also provided to support the linear analysis. While the dynamics and analysis approach presented can be applied to the general class of spin stabilized space. . .
Date: 08/2009 Publisher: AIAA Guidance, Navigation, and Control Conference DOI: 10.2514/6.2009-6203 Available at: http://arc.aiaa.org/doi/pdf/10.2514/6.2009-6203
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Authors: McCollough J. P., Quinn J. M., Starks M. J., and Johnston W R
Title: Intelligent Sampling of Hazardous Particle Populations in Resource-Constrained Environments
Abstract: Sampling of anomaly-causing space environment drivers is necessary for both real-time operations and satellite design efforts, and optimizing measurement sampling helps minimize resource demands. Relating these measurements to spacecraft anomalies requires the ability to resolve spatial and temporal variability in the energetic charged particle hazard of interest. Here we describe a method for sampling particle fluxes informed by magnetospheric phenomenology so that, along a given trajectory, the variations from both temporal dynamics and spatial structure are adequately captured while minimizing oversampling. We describe the coordinates, sampling method, and specific regions and parameters employed. We compare resulting sampling cadences with data from spacecraft spanning the regions of i. . .
Date: 10/2017 Publisher: Space Weather DOI: 10.1002/2017SW001629 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017SW001629/full
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Authors: McCarthy Michael P., Millan Robyn M., Sample John G., and Smith David M.
Title: Radiation belt losses observed from multiple stratospheric balloons over Antarctica
Abstract: Relativistic electrons, trapped by Earth's magnetic field, have received increasing attention since increasing numbers of commercial and research spacecraft traverse regions of high radiation flux. The Van Allen probes were launched into Earth's radiation belts in September 2012, making comprehensive measurements of charged particle fluxes and electromagnetic fields, with the objective of a better understanding of the processes that modulate radiation belt fluxes. Because losses of radiation belt electrons to Earth's atmosphere are very difficult to measure from high altitude spacecraft, a balloon-based program, consisting of campaigns in January 2013 and 2014, was funded to measure losses in conjunction with the Van Allen probes mission. We present results from both balloon campaigns, whi. . .
Date: 08/2014 Publisher: IEEE DOI: 10.1109/URSIGASS.2014.6929960 Available at: http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6929960
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Authors: Mazur J, Friesen L, Lin A, Mabry D, Katz N, et al.
Title: The Relativistic Proton Spectrometer (RPS) for the Radiation Belt Storm Probes Mission
Abstract: The Relativistic Proton Spectrometer (RPS) on the Radiation Belt Storm Probes spacecraft is a particle spectrometer designed to measure the flux, angular distribution, and energy spectrum of protons from ∼60 MeV to ∼2000 MeV. RPS will investigate decades-old questions about the inner Van Allen belt proton environment: a nearby region of space that is relatively unexplored because of the hazards of spacecraft operation there and the difficulties in obtaining accurate proton measurements in an intense penetrating background. RPS is designed to provide the accuracy needed to answer questions about the sources and losses of the inner belt protons and to obtain the measurements required for the next-generation models of trapped protons in the magnetosphere. In addition to detailed informati. . .
Date: 11/2013 Publisher: Space Science Reviews Pages: 221-261 DOI: 10.1007/s11214-012-9926-9 Available at: http://link.springer.com/article/10.1007%2Fs11214-012-9926-9
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Authors: Mazur J E, O'Brien T P, Looper M D, and Blake J B
Title: Large anisotropies of >60 MeV protons throughout the inner belt observed with the Van Allen Probes mission
Abstract: We report large directional anisotropies of >60 MeV protons using instrumentation on the Van Allen Probes. The combination of a spinning satellite and measurements from the Relativistic Proton Spectrometer instruments that are insensitive to protons outside the instrument field of view together yield a new look at proton radial gradients. The relatively large proton gyroradius at 60 MeV couples with the radial gradients to produce large (maximum ~10:1) flux anisotropies depending on (i) whether the proton guiding center was above or below the Van Allen Probes spacecraft and (ii) the sign of the local flux gradient. In addition to these newly measured anisotropies, below ~2000 km we report a new effect of systematically changing minimum altitude on some proton drift shells that furthe. . .
Date: 06/2014 Publisher: Geophysical Research Letters Pages: 3738 - 3743 DOI: 10.1002/grl.v41.1110.1002/2014GL060029 Available at: http://doi.wiley.com/10.1002/grl.v41.11http://doi.wiley.com/10.1002/2014GL060029
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Authors: Maurer Richard, Goldsten J O, Peplowski P N, Holmes-Siedle A G, Butler Michael, et al.
Title: Early Results from the Engineering Radiation Monitor (ERM) and Solar Cell Monitor on the Van Allen Probes Mission
Abstract: The Engineering Radiation Monitor (ERM) measures dose, dose rate and charging currents on the Van Allen Probes mission to study the dynamics of earth's Van Allen radiation belts. Early results from this monitor show a variation in dose rates with time, a correlation between the dosimeter and charging current data, a map of charging current versus orbit altitude and a comparison of cumulative dose to pre-launch modeling after 260 days. Solar cell degradation monitor patches track the decrease in solar array output as displacement damage accumulates.
Date: 11/2013 Publisher: IEEE DOI: 10.1109/TNS.2013.2281937 Available at: http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6651707
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Authors: Maurer R H, Goldsten J O, Butler M. H., and Fretz K.
Title: Five Year Results from the Engineering Radiation Monitor (ERM) and Solar Cell Monitor on the Van Allen Probes Mission
Abstract: The Engineering Radiation Monitor (ERM) measures dose, dose rate and charging currents on the Van Allen Probes mission to study the dynamics of Earth's Van Allen radiation belts. Over five years, results from this monitor show a variation in dose rates with time, a correlation between the dosimeter and charging current data and a comparison of cumulative dose to pre‐launch modeling. Solar cell degradation monitor patches track the decrease in solar array output as displacement damage accumulates. The Solar Cell Monitor shows ~33% cumulative degradation in maximum power after 5.1 years of the mission. The desire to extend the mission to ~2500 days from 800 days created increased requirements for the ionizing radiation hardness of spacecraft and science instrument electronics. We describe . . .
Date: 09/2018 Publisher: Space Weather DOI: 10.1029/2018SW001910 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018SW001910
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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: Mauk B H
Title: Comparative Investigation of the Energetic Ion Spectra Comprising the Magnetospheric Ring Currents of the Solar System
Abstract: Investigated here are factors that control the intensities and shapes of energetic ion spectra that make up the ring current populations of the strongly magnetized planets of the solar system, specifically those of Earth, Jupiter, Saturn, Uranus, and Neptune. Following a previous and similar comparative investigation of radiation belt electrons, we here turn our attention to ions. Specifically, we examine the possible role of the differential ion Kennel-Petschek limit, as moderated by Electromagnetic Ion Cyclotron (EMIC) waves, as a standard for comparing the most intense ion spectra within the strongly magnetized planetary magnetospheres. In carrying out this investigation, the substantial complexities engendered by the very different ion composition distributions of these diverse magneto. . .
Date: 11/2014 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2014JA020392 Available at: http://doi.wiley.com/10.1002/2014JA020392
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Authors: Mauk Barry H., Sibeck David G., and Kessel Ramona L.
Title: Journal Special Collection Explores Early Results From the Van Allen Probes Mission
Abstract: The processes governing the charged particle populations in the radiation belts encircling Earth have been the subject of intense interest and increasing concern since their discovery by James Van Allen and his team more than 50 years ago [Baker et al., 2013]. Intense interest continues because we still do not know how the various processes work in concert to enhance, remove, and transport particle radiation. Concern is ongoing because the Van Allen radiation belts pose hazards to astronauts and our ever-growing fleet of spacecraft with increasingly sensitive components.
Date: 04/2014 Publisher: Eos, Transactions American Geophysical Union Pages: 112 - 112 DOI: 10.1002/eost.v95.1310.1002/2014EO130007 Available at: http://doi.wiley.com/10.1002/eost.v95.13http://doi.wiley.com/10.1002/2014EO130007
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Authors: Mauk B H
Title: Analysis of EMIC-wave-moderated flux limitation of measured energetic ion spectra in multispecies magnetospheric plasmas
Abstract: A differential Kennel-Petschek (KP) flux limit for magnetospheric energetic ions is devised taking into account multiple ion species effects on electromagnetic ion cyclotron (EMIC) waves that scatter the ions. The idea is that EMIC waves may limit the highest ion intensities during acceleration phases of storms and substorms (~ hour) while other mechanisms (e.g., charge exchange) may account for losses below those limits and over longer periods of time. This approach is applied to published Earth magnetosphere energetic ion spectra (~ keV to ~1 MeV) for radial positions (L) 3 to 6.7 RE. The flatness of the most intense spectral shapes for <100 keV indicate sculpting by just such a mechanism, but modifications of traditional KP parameters are needed to account for maximum fluxes up to 5. . .
Date: 08/2013 Publisher: Geophysical Research Letters Pages: 3804 - 3808 DOI: 10.1002/grl.50789 Available at: http://doi.wiley.com/10.1002/grl.50789
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Authors: Matsui H., Torbert R B, Spence H E, Argall M. R., Alm L., et al.
Title: Relativistic electron increase during chorus wave activities on the 6-8 March 2016 geomagnetic storm
Abstract: There was a geomagnetic storm on 6–8 March 2016, in which Van Allen Probes A and B separated by ∼2.5 h measured increase of relativistic electrons with energies ∼ several hundred keV to 1 MeV. Simultaneously, chorus waves were measured by both Van Allen Probes and Magnetospheric Multiscale (MMS) mission. Some of the chorus elements were rising-tones, possibly due to nonlinear effects. These measurements are compared with a nonlinear theory of chorus waves incorporating the inhomogeneity ratio and the field equation. From this theory, a chorus wave profile in time and one-dimensional space is simulated. Test particle calculations are then performed in order to examine the energization rate of electrons. Some electrons are accelerated, although more electrons are decelerated. The measu. . .
Date: 10/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024540 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA024540/full
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Authors: Matsui H., Paulson K. W., Torbert R B, Spence H E, Kletzing C A, et al.
Title: Nonlinearity in chorus waves during a geomagnetic storm on 1 November 2012
Abstract: In this study, we investigate the possibility of nonlinearity in chorus waves during a geomagnetic storm on 1 November 2012. The data we use were measured by the Van Allen Probe B. Wave data and plasma sheet electron data are analyzed. Chorus waves were frequently measured in the morning side during the main phase of this storm. Large-amplitude chorus waves were seen of the order of ∼0.6 nT and >7 mV/m, which are similar to or larger than the typical ULF waves. The waves quite often consist of rising tones during the burst sampling. Since the rising tone is known as a signature of nonlinearity, a large portion of the waves are regarded as nonlinear at least during the burst sampling periods. These results underline the importance of nonlinearity in the dynamics of chorus waves. We furthe. . .
Date: 01/2016 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2015JA021772 Available at: http://doi.wiley.com/10.1002/2015JA021772
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Authors: Matsuda Shoya, Kasahara Yoshiya, and Kletzing Craig A.
Title: Variation in crossover frequency of EMIC waves in plasmasphere estimated from ion cyclotron whistler waves observed by Van Allen Probe A
Abstract: We report variations in the propagation of the H+ band ion cyclotron whistlers observed by Van Allen Probe A. Ion cyclotron whistlers are one of the EMIC (electromagnetic ion cyclotron) waves generated by mode conversion from lightning whistlers. Crossover frequency is an important frequency for the ion cyclotron whistlers, which is a function of the variations in the local heavy-ion composition. We surveyed waveform data obtained by the Electric and Magnetic Field Instrument and Integrated Science instrument and found that 3461 H+ band ion cyclotron whistlers were observed from 572 km to 5992 km in altitude. The main finding is that the crossover frequencies of the observed events decreased with increasing altitude. These results support the hypothesis that the total heavy-ion density dec. . .
Date: 01/2016 Publisher: Geophysical Research Letters Pages: 28 - 34 DOI: 10.1002/2015GL066893 Available at: http://doi.wiley.com/10.1002/2015GL066893
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Authors: Martinez-Calderon Claudia, Shiokawa Kazuo, Miyoshi Yoshizumi, Keika Kunihiro, Ozaki Mitsunori, et al.
Title: ELF/VLF wave propagation at subauroral latitudes: Conjugate observation between the ground and Van Allen Probes A
Abstract: We report simultaneous observation of ELF/VLF emissions, showing similar spectral and frequency features, between a VLF receiver at Athabasca (ATH), Canada, (L = 4.3) and Van Allen Probes A (Radiation Belt Storm Probes (RBSP) A). Using a statistical database from 1 November 2012 to 31 October 2013, we compared a total of 347 emissions observed on the ground with observations made by RBSP in the magnetosphere. On 25 February 2013, from 12:46 to 13:39 UT in the dawn sector (04–06 magnetic local time (MLT)), we observed a quasiperiodic (QP) emission centered at 4 kHz, and an accompanying short pulse lasting less than a second at 4.8 kHz in the dawn sector (04–06 MLT). RBSP A wave data showed both emissions as right-hand polarized with their Poynting vector earthward to the Northern Hemisp. . .
Date: 06/2016 Publisher: Journal of Geophysical Research: Space Physics Pages: 5384 - 5393 DOI: 10.1002/jgra.v121.610.1002/2015JA022264 Available at: http://doi.wiley.com/10.1002/2015JA022264
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Authors: Mann I. R., Ozeke L. G., Morley S. K., Murphy K. R., Claudepierre S G, et al.
Title: Reply to 'The dynamics of Van Allen belts revisited'
Abstract: N/A
Date: 02/2019 Publisher: Nature Physics Pages: 103 - 104 DOI: 10.1038/nphys4351 Available at: http://www.nature.com/doifinder/10.1038/nphys4351
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Authors: Mann Ian R., Lee E. A., Claudepierre S G, Fennell J. F., Degeling A., et al.
Title: Discovery of the action of a geophysical synchrotron in the Earth’s Van Allen radiation belts
Abstract: Although the Earth’s Van Allen radiation belts were discovered over 50 years ago, the dominant processes responsible for relativistic electron acceleration, transport and loss remain poorly understood. Here we show evidence for the action of coherent acceleration due to resonance with ultra-low frequency waves on a planetary scale. Data from the CRRES probe, and from the recently launched multi-satellite NASA Van Allen Probes mission, with supporting modeling, collectively show coherent ultra-low frequency interactions which high energy resolution data reveals are far more common than either previously thought or observed. The observed modulations and energy-dependent spatial structure indicate a mode of action analogous to a geophysical synchrotron; this new mode of response represents . . .
Date: 11/2013 Publisher: Nature Communications DOI: 10.1038/ncomms3795 Available at: http://www.nature.com/doifinder/10.1038/ncomms3795
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Authors: Mann I. R., Ozeke L. G., Murphy K. R., Claudepierre S G, Turner D. L., et al.
Title: Explaining the dynamics of the ultra-relativistic third Van Allen radiation belt
Abstract: Since the discovery of the Van Allen radiation belts over 50 years ago, an explanation for their complete dynamics has remained elusive. Especially challenging is understanding the recently discovered ultra-relativistic third electron radiation belt. Current theory asserts that loss in the heart of the outer belt, essential to the formation of the third belt, must be controlled by high-frequency plasma wave–particle scattering into the atmosphere, via whistler mode chorus, plasmaspheric hiss, or electromagnetic ion cyclotron waves. However, this has failed to accurately reproduce the third belt. Using a datadriven, time-dependent specification of ultra-low-frequency (ULF) waves we show for the first time how the third radiation belt is established as a simple, elegant consequence o. . .
Date: 06/2016 Publisher: Nature Physics DOI: 10.1038/nphys3799 Available at: http://www.nature.com/doifinder/10.1038/nphys3799
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Authors: Mann Ian R., and Ozeke Louis G.
Title: How quickly, how deeply, and how strongly can dynamical outer boundary conditions impact Van Allen radiation belt morphology?
Abstract: Here we examine the speed, strength, and depth of the coupling between dynamical variations of ultrarelativistic electron flux at the outer boundary and that in the heart of the outer radiation belt. Using ULF wave radial diffusion as an exemplar, we show how changing boundary conditions can completely change belt morphology even under conditions of identical wave power. In the case of ULF wave radial diffusion, the temporal dynamics of a new source population or a sink of electron flux at the outer plasma sheet boundary can generate a completely opposite response which reaches deep into the belt under identical ULF wave conditions. Very significantly, here we show that such coupling can occur on timescales much faster than previously thought. We show that even on timescales ~1 h, change. . .
Date: 06/2016 Publisher: Journal of Geophysical Research: Space Physics Pages: 5553 - 5558 DOI: 10.1002/jgra.v121.610.1002/2016JA022647 Available at: http://doi.wiley.com/10.1002/2016JA022647
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Authors: Mann I. R., Usanova M. E., Murphy K., Robertson M. T., Milling D. K., et al.
Title: Spatial localization and ducting of EMIC waves: Van Allen Probes and ground-based observations
Abstract: On 11 October 2012, during the recovery phase of a moderate geomagnetic storm, an extended interval (> 18 h) of continuous electromagnetic ion cyclotron (EMIC) waves was observed by Canadian Array for Real-time Investigations of Magnetic Activity and Solar-Terrestrial Environment Program induction coil magnetometers in North America. At around 14:15 UT, both Van Allen Probes B and A (65° magnetic longitude apart) in conjunction with the ground array observed very narrow (ΔL ~ 0.1–0.4) left-hand polarized EMIC emission confined to regions of mass density gradients at the outer edge of the plasmasphere at L ~ 4. EMIC waves were seen with complex polarization patterns on the ground, in good agreement with model results from Woodroffe and Lysak (2012) and consistent with Earth's . . .
Date: 02/2014 Publisher: Geophysical Research Letters Pages: 785 - 792 DOI: 10.1002/2013GL058581 Available at: http://doi.wiley.com/10.1002/2013GL058581
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Authors: Maldonado Armando A., Chen Lunjin, Claudepierre Seth G., Bortnik Jacob, Thorne Richard M, et al.
Title: Electron butterfly distribution modulation by magnetosonic waves
Abstract: The butterfly pitch angle distribution is observed as a dip in an otherwise normal distribution of electrons centered about αeq=90°. During storm times, the formation of the butterfly distribution on the nightside magnetosphere has been attributed to L shell splitting combined with magnetopause shadowing and strong positive radial flux gradients. It has been shown that this distribution can be caused by combined chorus and magnetosonic wave scattering where the two waves work together but at different local times. Presented in our study is an event on 21 August 2013, using Van Allen Probe measurements, where a butterfly distribution formation is modulated by local magnetosonic coherent magnetosonic waves intensity. Transition from normal to butterfly distributions coincides with rising m. . .
Date: 04/2016 Publisher: Geophysical Research Letters DOI: 10.1002/2016GL068161 Available at: http://doi.wiley.com/10.1002/2016GL068161http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2F2016GL068161http://api.wiley.com/onlinelibrary/chorus/v1/articles/10.1002%2F2016GL068161
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Authors: Malaspina D. M., Ergun R. E., Sturner A., Wygant J R, Bonnell J W, et al.
Title: Chorus waves and spacecraft potential fluctuations: Evidence for wave-enhanced photoelectron escape
Abstract: Chorus waves are important for electron energization and loss in Earth's radiation belts and inner magnetosphere. Because the amplitude and spatial distribution of chorus waves can be strongly influenced by plasma density fluctuations and spacecraft floating potential can be a diagnostic of plasma density, the relationship between measured potential and chorus waves is examined using Van Allen Probes data. While measured potential and chorus wave electric fields correlate strongly, potential fluctuation properties are found not to be consistent with plasma density fluctuations on the timescales of individual chorus wave packets. Instead, potential fluctuations are consistent with enhanced photoelectron escape driven by chorus wave electric fields. Enhanced photoelectron escape may result i. . .
Date: 01/2014 Publisher: Geophysical Research Letters Pages: 236 - 243 DOI: 10.1002/2013GL058769 Available at: http://doi.wiley.com/10.1002/2013GL058769
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Authors: Malaspina David M., Wygant John R., Ergun Robert E., Reeves Geoff D., Skoug Ruth M., et al.
Title: Electric field structures and waves at plasma boundaries in the inner magnetosphere
Abstract: Recent observations by the Van Allen Probes spacecraft have demonstrated that a variety of electric field structures and nonlinear waves frequently occur in the inner terrestrial magnetosphere, including phase space holes, kinetic field line resonances, nonlinear whistler mode waves, and several types of double layer. However, it is unclear whether such structures and waves have a significant impact on the dynamics of the inner magnetosphere, including the radiation belts and ring current. To make progress toward quantifying their importance, this study statistically evaluates the correlation of such structures and waves with plasma boundaries. A strong correlation is found. These statistical results, combined with observations of electric field activity at propagating plasma boundaries, a. . .
Date: 05/2015 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2015JA021137 Available at: http://doi.wiley.com/10.1002/2015JA021137
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Authors: Malaspina D. M., Andersson L., Ergun R. E., Wygant J R, Bonnell J W, et al.
Title: Nonlinear Electric Field Structures in the Inner Magnetosphere
Abstract: Van Allen Probes observations are presented which demonstrate the presence of nonlinear electric field structures in the inner terrestrial magnetosphere (< 6 RE). A range of structures are observed, including phase space holes and double layers.These structures are observed over several Earth radii in radial distance and over a wide range of magnetic local times. They are observed in the dusk, midnight, and dawn sectors, with the highest concentration pre-midnight. Some nonlinear electric field structures are observed to coincide with dipolarizations of the magnetic field and increases in electron energy flux for energies between 1 keV and 30 keV. Nonlinear electric field structures possess isolated impulsive electric fields, often with a significant component parallel to the ambient m. . .
Date: 08/2014 Publisher: Geophysical Research Letters DOI: 10.1002/2014GL061109 Available at: http://doi.wiley.com/10.1002/2014GL061109
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Authors: Malaspina David M., Jaynes Allison N, Hospodarsky George, Bortnik Jacob, Ergun Robert E, et al.
Title: Statistical Properties of Low Frequency Plasmaspheric Hiss
Abstract: Plasmaspheric hiss is an important wave mode for the dynamics of inner terrestrial magnetosphere plasma populations. It acts to scatter high energy electrons out of trapped orbits about Earth and into the atmosphere, defining the inner edge of the radiation belts over a range of energies. A low-frequency component of hiss was recently identified and is important for its ability to interact with higher energy electrons compared to typically considered hiss frequencies. This study compares the statistical properties of low and high frequency plasmaspheric hiss in the terrestrial magnetosphere, demonstrating that they are statistically distinct wave populations. Low frequency hiss shows different behavior in frequency space, different spatial localization (in magnetic local time and radial di. . .
Date: 07/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024328 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA024328/full
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Authors: Malaspina David M., Claudepierre Seth G., Takahashi Kazue, Jaynes Allison N., Elkington Scot R, et al.
Title: Kinetic Alfvén Waves and Particle Response Associated with a Shock-Induced, Global ULF Perturbation of the Terrestrial Magnetosphere
Abstract: On 2 October 2013, the arrival of an interplanetary shock compressed the Earth's magnetosphere and triggered a global ULF (ultra low frequency) oscillation. The Van Allen Probe B spacecraft observed this large-amplitude ULF wave in situ with both magnetic and electric field data. Broadband waves up to approximately 100 Hz were observed in conjunction with, and modulated by, this ULF wave. Detailed analysis of fields and particle data reveals that these broadband waves are Doppler-shifted kinetic Alfvén waves. This event suggests that magnetospheric compression by interplanetary shocks can induce abrupt generation of kinetic Alfvén waves over large portions of the inner magnetosphere, potentially driving previously unconsidered wave-particle interactions throughout the inner magnetosphere. . .
Date: 11/2015 Publisher: Geophysical Research Letters DOI: 10.1002/2015GL065935 Available at: http://doi.wiley.com/10.1002/2015GL065935http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2F2015GL065935
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Authors: Malaspina David M., Ripoll Jean-Francois, Chu Xiangning, Hospodarsky George, and Wygant John
Title: Variation in Plasmaspheric Hiss Wave Power With Plasma Density
Abstract: Plasmaspheric hiss waves are commonly observed in the inner magnetosphere. These waves efficiently scatter electrons, facilitating their precipitation into the atmosphere. Predictive inner magnetosphere simulations often model hiss waves using parameterized empirical maps of observed hiss power. These maps nearly always include parameterization by magnetic L value. In this work, data from the Van Allen Probes are used to compare variation in hiss wave power with variation in both L value and cold plasma density. It is found that for L> 2.5, plasmaspheric hiss wave power increases with plasma density. For L> 3, this increase is stronger and occurs regardless of L value and for all local times. This result suggests that the current paradigm for parameterizing hiss wave power in many magnetos. . .
Date: 09/2018 Publisher: Geophysical Research Letters DOI: 10.1029/2018GL078564 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL078564
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Authors: Malaspina David M., Ukhorskiy Aleksandr, Chu Xiangning, and Wygant John
Title: A census of plasma waves and structures associated with an injection front in the inner magnetosphere
Abstract: Now that observations have conclusively established that the inner magnetosphere is abundantly populated with kinetic electric field structures and nonlinear waves, attention has turned to quantifying the ability of these structures and waves to scatter and accelerate inner magnetospheric plasma populations. A necessary step in that quantification is determining the distribution of observed structure and wave properties (e.g. occurrence rates, amplitudes, spatial scales). Kinetic structures and nonlinear waves have broadband signatures in frequency space and consequently, high resolution time domain electric and magnetic field data is required to uniquely identify such structures and waves as well as determine their properties. However, most high resolution fields data is collected with a . . .
Date: 02/2018 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA025005 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA025005/full
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Authors: Malaspina David M., Jaynes Allison N., é Cory, Bortnik Jacob, Thaller Scott A., et al.
Title: The distribution of plasmaspheric hiss wave power with respect to plasmapause location
Abstract: In this work, Van Allen Probes data are used to derive terrestrial plasmaspheric hiss wave power distributions organized by (1) distance away from the plasmapause and (2) plasmapause distance from Earth. This approach is in contrast to the traditional organization of hiss wave power by L parameter and geomagnetic activity. Plasmapause-sorting reveals previously unreported and highly repeatable features of the hiss wave power distribution, including a regular spatial distribution of hiss power with respect to the plasmapause, a standoff distance between peak hiss power and the plasmapause, and frequency-dependent spatial localization of hiss. Identification and quantification of these features can provide insight into hiss generation and propagation and will facilitate improved parameteriza. . .
Date: 08/2016 Publisher: Geophysical Research Letters Pages: 7878 - 7886 DOI: 10.1002/2016GL069982 Available at: http://doi.wiley.com/10.1002/2016GL069982
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Authors: Makela Jonathan J., Harding Brian J., Meriwether John W., Mesquita Rafael, Sanders Samuel, et al.
Title: Storm time response of the mid-latitude thermosphere: Observations from a network of Fabry-Perot interferometers
Abstract: Observations of thermospheric neutral winds and temperatures obtained during a geomagnetic storm on 2 October 2013 from a network of six Fabry-Perot interferometers (FPIs) deployed in the midwest United States are presented. Coincident with the commencement of the storm, the apparent horizontal wind is observed to surge westward and southward (towards the equator). Simultaneous to this surge in the apparent horizontal winds, an apparent downward wind of approximately 100 m/s lasting for 6 hours is observed. The apparent neutral temperature is observed to increase by approximately 400 K over all of the sites. Observations from an all-sky imaging system operated at the Millstone Hill observatory indicate the presence of a stable auroral red (SAR) arc and diffuse red aurora during this . . .
Date: 08/2014 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2014JA019832 Available at: http://doi.wiley.com/10.1002/2014JA019832
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Authors: Mager Olga V., Chelpanov Maksim A., Mager Pavel N., Klimushkin Dmitri Yu., and Berngardt Oleg I.
Title: Conjugate Ionosphere‐Magnetosphere Observations of a Sub‐Alfvénic Compressional Intermediate‐ m Wave: A Case Study Using EKB Radar and Van Allen Probes
Abstract: A Pc5 wave was simultaneously observed in the ionosphere by EKB radar and in the magnetosphere by both Van Allen Probe spacecraft within a substorm activity. The wave was located in the nightside, in 1.5‐ to 3‐hr magnetic local time sector, and in the region corresponding to the magnetic shells with maximal distances 4.6–7.8 Earth's radii. As it was found using both the radar and spacecraft data, the wave had frequency of about 1.8 mHz and azimuthal wave number m≈−10; that is, the wave was westward propagating. The EKB radar data revealed the equatorward wave propagating in the ionosphere, which corresponded to the earthward propagation in the magnetosphere. Furthermore, the field‐aligned magnetic component was approximately 2 times larger than both transverse components and ac. . .
Date: 05/2019 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2019JA026541 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019JA026541
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Authors: Mager Pavel N., Mikhailova Olga S., Mager Olga V., and Klimushkin Dmitri Yu.
Title: Eigenmodes of the transverse Alfvénic resonator at the plasmapause: a Van Allen Probes case study
Abstract: A Pc4 ULF wave was detected at spacecraft B of the Van Allen Probes at the plasmapause. A distinctive feature of this wave is the strong periodical modulation of the wave. It is assumed that this modulation is a beating of oscillations close in frequency: at least two harmonics with frequencies of 15.3 and 13.6 MHz are found. It is shown that these harmonics can be the eigenmodes of the transverse resonator at the local maximum of the Alfvén velocity. In addition, the observed wave was in a drift resonance with energetic 80 keV protons and could be generated by an unstable “bump on tail” distribution of protons simultaneously observed with the wave. The estimate of the azimuthal wave number m made from the drift resonance condition gives a value of about −100, i.e., it is a westward. . .
Date: 09/2018 Publisher: Geophysical Research Letters DOI: 10.1029/2018GL079596 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL079596
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Authors: Ma Q, Li W, Thorne R M, Bortnik J, Reeves G D, et al.
Title: Diffusive transport of several hundred keV electrons in the Earth's slot region
Abstract: We investigate the gradual diffusion of energetic electrons from the inner edge of the outer radiation belt into the slot region. The Van Allen Probes observed slow inward diffusion and decay of ~200-600 keV electrons following the intense geomagnetic storm that occurred on 17 March 2013. During the 10-day non-disturbed period following the storm, the peak of electron fluxes gradually moved from L~2.7 to L~2.4, and the flux levels decreased by a factor of ~2-4 depending on the electron energy. We simulated the radial intrusion and decay of electrons using a 3-dimentional diffusion code, which reproduced the energy-dependent transport of electrons from ~100 keV to 1 MeV in the slot region. At energies of 100-200 keV, the electrons experience fast transport across the slot region due to the . . .
Date: 09/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024452 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA024452/full
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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: Ma Q, Li W, Chen L, Thorne R M, Kletzing C A, et al.
Title: The trapping of equatorial magnetosonic waves in the Earth's outer plasmasphere
Abstract: We investigate the excitation and propagation of equatorial magnetosonic waves observed by the Van Allen Probes and describe evidence for a trapping mechanism for magnetosonic waves in the Earth's plasmasphere. Intense equatorial magnetosonic waves were observed inside the plasmasphere in association with a pronounced proton ring distribution, which provides free energy for wave excitation. Instability analysis along the inbound orbit demonstrates that broadband magnetosonic waves can be excited over a localized spatial region near the plasmapause. The waves can subsequently propagate into the inner plasmasphere and remain trapped over a limited radial extent, consistent with the predictions of near-perpendicular propagation. By performing a similar analysis on another observed magnetosoni. . .
Date: 09/2014 Publisher: Geophysical Research Letters Pages: 6307 - 6313 DOI: 10.1002/2014GL061414 Available at: http://doi.wiley.com/10.1002/2014GL061414
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Authors: Ma Q, Artemyev A. V., Mourenas D., Li W, Thorne R M, et al.
Title: Very Oblique Whistler Mode Propagation in the Radiation Belts: Effects of Hot Plasma and Landau Damping
Abstract: Satellite observations of a significant population of very oblique chorus waves in the outer radiation belt have fueled considerable interest in the effects of these waves on energetic electron scattering and acceleration. However, corresponding diffusion rates are extremely sensitive to the refractive index N, controlled by hot plasma effects including Landau damping and wave dispersion modifications by suprathermal (15–100 eV) electrons. A combined investigation of wave and electron distribution characteristics obtained from the Van Allen Probes shows that peculiarities of the measured electron distribution significantly reduce Landau damping, allowing wave propagation with high N ∼ 100–200. Further comparing measured refractive indexes with theoretical estimates incorporating hot . . .
Date: 12/2017 Publisher: Geophysical Research Letters DOI: 10.1002/2017GL075892 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017GL075892/full
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Authors: Ma Q, Li W, Bortnik J, Thorne R M, Chu X., et al.
Title: Quantitative Evaluation of Radial Diffusion and Local Acceleration Processes During GEM Challenge Events
Abstract: We simulate the radiation belt electron flux enhancements during selected Geospace Environment Modeling (GEM) challenge events to quantitatively compare the major processes involved in relativistic electron acceleration under different conditions. Van Allen Probes observed significant electron flux enhancement during both the storm time of 17–18 March 2013 and non–storm time of 19–20 September 2013, but the distributions of plasma waves and energetic electrons for the two events were dramatically different. During 17–18 March 2013, the SYM‐H minimum reached −130 nT, intense chorus waves (peak Bw ~140 pT) occurred at 3.5 < L < 5.5, and several hundred keV to several MeV electron fluxes increased by ~2 orders of magnitude mostly at 3.5 < L < 5.5. During 19–20 September 2013, th. . .
Date: 03/2018 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA025114 Available at: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017JA025114
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Authors: Ma Q, Li W, Thorne R M, Ni B, Kletzing C A, et al.
Title: Modeling inward diffusion and slow decay of energetic electrons in the Earth's outer radiation belt
Abstract: A new 3D diffusion code is used to investigate the inward intrusion and slow decay of energetic radiation belt electrons (>0.5 MeV) observed by the Van Allen Probes during a 10-day quiet period in March 2013. During the inward transport the peak differential electron fluxes decreased by approximately an order of magnitude at various energies. Our 3D radiation belt simulation including radial diffusion and pitch angle and energy diffusion by plasmaspheric hiss and Electromagnetic Ion Cyclotron (EMIC) waves reproduces the essential features of the observed electron flux evolution. The decay timescales and the pitch angle distributions in our simulation are consistent with the Van Allen Probes observations over multiple energy channels. Our study suggests that the quiet-time energetic electro. . .
Date: 02/2015 Publisher: Geophysical Research Letters DOI: 10.1002/2014GL062977 Available at: http://doi.wiley.com/10.1002/2014GL062977
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Authors: Ma Q, Li W, Yue C., Thorne R M, Bortnik J, et al.
Title: Ion Heating by Electromagnetic Ion Cyclotron Waves and Magnetosonic Waves in the Earth's Inner Magnetosphere
Abstract: Electromagnetic ion cyclotron (EMIC) waves and magnetosonic waves are commonly observed in the Earth's magnetosphere associated with enhanced ring current activity. Using wave and ion measurements from the Van Allen Probes, we identify clear correlations between the hydrogen‐ and helium‐band EMIC waves with the enhancement of trapped helium and oxygen ion fluxes, respectively. We calculate the diffusion coefficients of different ion species using quasi‐linear theory to understand the effects of resonant scattering by EMIC waves. Our calculations indicate that EMIC waves can cause pitch angle scattering loss of several keV to hundreds of keV ions, and heating of tens of eV to several keV helium and oxygen ions by hydrogen‐ and helium‐band EMIC waves, respectively. Moreover, we fou. . .
Date: 06/2019 Publisher: Geophysical Research Letters Pages: 6258 - 6267 DOI: 10.1029/2019GL083513 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019GL083513
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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: Ma Qianli, Li Wen, Thorne Richard M, Bortnik Jacob, Kletzing C A, et al.
Title: Electron scattering by magnetosonic waves in the inner magnetosphere
Abstract: We investigate the importance of electron scattering by magnetosonic waves in the Earth's inner magnetosphere. A statistical survey of the magnetosonic wave amplitude and wave frequency spectrum, as a function of geomagnetic activity, is performed using the Van Allen Probes wave measurements, and is found to be generally consistent with the wave distribution obtained from previous spacecraft missions. Outside the plasmapause the statistical frequency distribution of magnetosonic waves follows the variation of the lower hybrid resonance frequency, but this trend is not observed inside the plasmasphere. Drift and bounce averaged electron diffusion rates due to magnetosonic waves are calculated using a recently developed analytical formula. The resulting time scale of electron energization du. . .
Date: 12/2015 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2015JA021992 Available at: http://doi.wiley.com/10.1002/2015JA021992http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2F2015JA021992
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Authors: Ma Qianli, Mourenas Didier, Li Wen, Artemyev Anton, and Thorne Richard M
Title: VLF waves from ground-based transmitters observed by the Van Allen Probes: Statistical model and effects on plasmaspheric electrons
Abstract: Whistler-mode Very Low Frequency (VLF) waves from powerful ground-based transmitters can resonantly scatter energetic plasmaspheric electrons and precipitate them into the atmosphere. A comprehensive 4-year statistics of Van Allen Probes measurements is carried out to assess their consequences on the dynamics of the inner radiation belt and slot region. Statistical models of the measured wave electric field power and of the inferred full wave magnetic amplitude are provided as a function of L, magnetic local time, season, and Kp over L=1-3, revealing the localization of VLF wave intensity and its variation with geomagnetic activity over 2012-2016. Since this VLF wave model can be directly used together with existing hiss and lightning-generated wave models in radiation belt simulation code. . .
Date: 06/2017 Publisher: Geophysical Research Letters DOI: 10.1002/2017GL073885 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017GL073885/full
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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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