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Van Allen Probes Bibliography is from August 2012 through September 2021 Notice:
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Found 53 entries in the Bibliography.
Showing entries from 1 through 50
| 2021 |
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Realistic electron diffusion rates and lifetimes due to scattering by electron holes AbstractPlasma sheet electron precipitation into the diffuse aurora is critical for magnetosphere-ionosphere coupling. Recent studies have shown that electron phase space holes can pitch-angle scatter electrons and may produce plasma sheet electron precipitation. These studies have assumed identical electron hole parameters to estimate electron scattering rates (Vasko et al., 2018). In this study, we have re-evaluated the efficiency of this scattering by incorporating realistic electron hole properties from direct spacecraf ... Shen, Yangyang; Vasko, Ivan; Artemyev, Anton; Malaspina, David; Chu, Xiangning; Angelopoulos, Vassilis; Zhang, Xiao-Jia; Published by: Journal of Geophysical Research: Space Physics Published on: 08/2021 YEAR: 2021 DOI: https://doi.org/10.1029/2021JA029380 diffuse aurora; electron pitch-angle scattering; electron phase space hole; Wave-particle interaction; electron lifetimes; broadband electrostatic fluctuations; Van Allen Probes |
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AbstractThe spatial scales of whistler-mode waves, determined by their generation process, propagation, and damping, are important for assessing the scaling and efficiency of wave-particle interactions affecting the dynamics of the radiation belts. We use multi-point wave measurements in 2013-2019 by two identically equipped Van Allen Probes spacecraft covering all MLTs at L=2-6 near the geomagnetic equator to investigate the spatial extent of active regions of chorus and hiss waves, their wave amplitude distribution in the ... Agapitov, O.; Mourenas, D.; Artemyev, A.; Breneman, A.; Bonnell, J.W.; Hospodarsky, G.; Wygant, J.; Published by: Journal of Geophysical Research: Space Physics Published on: 06/2021 YEAR: 2021 DOI: https://doi.org/10.1029/2020JA028998 chorus waves; chorus genration; Radiation belts; Van Allen Probes |
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Abstract We investigate relativistic electron precipitation events detected by POES in low-Earth orbit in close conjunction with Van Allen Probe A observations of EMIC waves near the geomagnetic equator. We show that the occurrence rate of > 0.7 MeV electron precipitation recorded by POES during those times strongly increases, reaching statistically significant levels when the minimum electron energy for cyclotron resonance with hydrogen or helium band EMIC waves at the equator decreases below ≃ 1.0 − 2.5 MeV, as expecte ... Zhang, X.-J.; Mourenas, D.; Shen, X.-C.; Qin, M.; Artemyev, A.; Ma, Q.; Li, W.; Hudson, M.; Angelopoulos, V.; Published by: Journal of Geophysical Research: Space Physics Published on: 04/2021 YEAR: 2021 DOI: https://doi.org/10.1029/2021JA029193 EMIC waves; relativistic electron precipitation; minimum resonant energy; Van Allen Probes; POES; Radiation belts |
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Generation of realistic short chorus wave packets Abstract Most lower-band chorus waves observed in the inner magnetosphere propagate under the form of moderately intense short wave packets with fast frequency and phase variations. Therefore, understanding the formation mechanism of such short wave packets is crucial for accurately modelling electron nonlinear acceleration or precipitation into the atmosphere by these waves. We compare chorus wave statistics from the Van Allen Probes with predictions from a simple model of short wave packet generation by wave superposition ... Nunn, D.; Zhang, X.-J.; Mourenas, D.; Artemyev, A.; Published by: Geophysical Research Letters Published on: 03/2021 YEAR: 2021 DOI: https://doi.org/10.1029/2020GL092178 chorus waves; Radiation belts; Wave-particle interaction; Van Allen Probes |
| 2020 |
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Energetic electron dynamics is highly affected by plasma waves through quasilinear and/or nonlinear interactions in the Earth s inner magnetosphere. In this letter, we provide physical explanations for a previously reported intriguing event from the Van Allen Probes observations, where bursts of electron butterfly distributions at tens of keV exhibit remarkable correlations with chorus waves. Both test particle and quasilinear simulations are used to reveal the formation mechanism for the bursts of electron butterfly distrib ... Gan, L.; Li, W.; Ma, Q.; Artemyev, A.; Albert, J.; Published by: Geophysical Research Letters Published on: 10/2020 YEAR: 2020 DOI: https://doi.org/10.1029/2020GL090749 butterfly distribution; chorus waves; Electron acceleration; Radiation belts; nonlinear interaction; Van Allen Probes |
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The flux of energetic electrons in the outer radiation belt shows a high variability. The interactions of electrons with very low frequency (VLF) chorus waves play a significant role in controlling the flux variation of these particles. Quantifying the effects of these interactions is crucially important for accurately modeling the global dynamics of the outer radiation belt and to provide a comprehensive description of electron flux variations over a wide energy range (from the source population of 30 keV electrons up to th ... Aryan, Homayon; Agapitov, Oleksiy; Artemyev, Anton; Mourenas, Didier; Balikhin, Michael; Boynton, Richard; Bortnik, Jacob; Published by: Journal of Geophysical Research: Space Physics Published on: 07/2020 YEAR: 2020 DOI: https://doi.org/10.1029/2020JA028018 electron lifetimes; Van Allen radiation belts; chorus waves; pitch angle diffusion coefficients; Van Allen Probes; Cluster |
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Whistler-mode hiss waves generally determine MeV electron lifetimes inside the plasmasphere. We use Van Allen Probes measurements to provide the first comprehensive statistical survey of plasmaspheric hiss-driven quasi-linear pitch-angle diffusion rates and lifetimes of MeV electrons as a function of L*, local time, and AE index, taking into account hiss power, electron plasma frequency to gyrofrequency ratio ωpe/Ωce, hiss frequency at peak power ωm, and cross correlations of these parameters. We find that during geomagne ... Agapitov, O.; Mourenas, D.; Artemyev, A.; Claudepierre, S.; Hospodarsky, G.; Bonnell, J.; Published by: Geophysical Research Letters Published on: 05/2020 YEAR: 2020 DOI: https://doi.org/10.1029/2020GL088052 electron lifetimes; plasmasphere; hiss waves; wave-particle interactions; Van Allen Probes |
| 2019 |
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Decay of Ultrarelativistic Remnant Belt Electrons Through Scattering by Plasmaspheric Hiss Ultrarelativistic electron remnant belts appear frequently following geomagnetic disturbances and are located in-between the inner radiation belt and a reforming outer belt. As remnant belts are relatively stable, here we explore the importance of hiss and electromagnetic ion cyclotron waves in controlling the observed decay rates of remnant belt ultrarelativistic electrons in a statistical way. Using measurements from the Van Allen Probes inside the plasmasphere for 25 remnant belt events that occurred between 2012 and 2017 ... Pinto, V.; Mourenas, D.; Bortnik, J.; Zhang, X.-J.; Artemyev, A.; Moya, P.; Lyons, L.; Published by: Journal of Geophysical Research: Space Physics Published on: Dec-07-2019 YEAR: 2019 DOI: 10.1029/2019JA026509 Decay rates; EMIC waves; MeV Electron Decay; Plasmaspheric Hiss; Radiation belts; Remnant Belt; Van Allen Probes |
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The magnetospheric driver of strong thermal emission velocity enhancement (STEVE) is investigated using conjugate observations when Van Allen Probes\textquoteright footprint directly crossed both STEVE and stable red aurora (SAR) arc. In the ionosphere, STEVE is associated with subauroral ion drift features, including electron temperature peak, density gradient, and westward ion flow. The SAR arc at lower latitudes corresponds to regions inside the plasmapause with isotropic plasma heating, which causes redline-only SAR emis ... Chu, Xiangning; Malaspina, David; Gallardo-Lacourt, Bea; Liang, Jun; Andersson, Laila; Ma, Qianli; Artemyev, Anton; Liu, Jiang; Ergun, Robert; Thaller, Scott; Akbari, Hassanali; Zhao, Hong; Larsen, Brian; Reeves, Geoffrey; Wygant, John; Breneman, Aaron; Tian, Sheng; Connors, Martin; Donovan, Eric; Archer, William; MacDonald, Elizabeth; Published by: Geophysical Research Letters Published on: 11/2019 YEAR: 2019 DOI: 10.1029/2019GL082789 aurora; kinetic Alfven wave; Plasmapause; STEVE; subauroral ion drift; table red auroral arc; Van Allen Probes |
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Nonlinear Electron Interaction With Intense Chorus Waves: Statistics of Occurrence Rates A comprehensive statistical analysis on 8 years of lower-band chorus wave packets measured by the Van Allen Probes and THEMIS spacecraft is performed to examine whether, when, and where these waves are above the theoretical threshold for nonlinear resonant wave-particle interaction. We find that \~5\textendash30\% of all chorus waves interact nonlinearly with \~30- to 300-keV electrons possessing equatorial pitch angles of >40\textdegree in the outer radiation belt, especially during disturbed (AE>500 nT) periods with energe ... Zhang, X.-J.; Mourenas, D.; Artemyev, A.; Angelopoulos, V.; Bortnik, J.; Thorne, R.; Kurth, W.; Kletzing, C.; Hospodarsky, G.; Published by: Geophysical Research Letters Published on: 06/2019 YEAR: 2019 DOI: 10.1029/2019GL083833 chorus waves; Electron acceleration; nonlinear wave particle interaction; THEMIS; Van Allen Probes; wave packet size |
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Electron scattering by chorus waves is an important mechanism that can lead to fast electron acceleration and loss in the outer radiation belt. Making use of Van Allen Probes measurements, we present the first statistical survey of megaelectron volt electron pitch angle and energy quasi-linear diffusion rates by chorus waves as a function of L-shell, local time, and AE index, taking into account the local electron plasma frequency to gyrofrequency ratio ωpe/Ωce, chorus wave frequency, and resonance wave amplitude. We demon ... Agapitov, O.; Mourenas, D.; Artemyev, A.; Hospodarsky, G.; Bonnell, J.W.; Published by: Geophysical Research Letters Published on: 05/2019 YEAR: 2019 DOI: 10.1029/2019GL083446 magnetosphere plasma density; quasi-linear scattering and acceleration; Van Allen Probes; wave-particle interactions |
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EMIC Wave-Driven Bounce Resonance Scattering of Energetic Electrons in the Inner Magnetosphere While electromagnetic ion cyclotron (EMIC) waves have been long studied as a scattering mechanism for ultrarelativistic (megaelectron volt) electrons via cyclotron-resonant interactions, these waves are also of the right frequency to resonate with the bounce motion of lower-energy (approximately tens to hundreds of kiloelectron volts) electrons. Here we investigate the effectiveness of this bounce resonance interaction to better determine the effects of EMIC waves on subrelativistic electron populations in Earth\textquoterig ... Blum, L.W.; Artemyev, A.; Agapitov, O.; Mourenas, D.; Boardsen, S.; Schiller, Q.; Published by: Journal of Geophysical Research: Space Physics Published on: 03/2019 YEAR: 2019 DOI: 10.1029/2018JA026427 bounce resonance; EMIC wave; energetic electrons; Radiation belts; Van Allen Probes |
| 2018 |
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Resonant electron interaction with whistler-mode chorus waves is recognized as one of the main drivers of radiation belt dynamics. For moderate wave intensity, this interaction is well described by quasi-linear theory. However, recent statistics of parallel propagating chorus waves have demonstrated that 5 - 20\% of the observed waves are sufficiently intense to interact nonlinearly with electrons. Such interactions include phase trapping and phase bunching (nonlinear scattering) effects not described by quasi-linear diffusi ... Vainchtein, D.; Zhang, X.-J.; Artemyev, A.; Mourenas, D.; Angelopoulos, V.; Thorne, R.; Published by: Journal of Geophysical Research: Space Physics Published on: 09/2018 YEAR: 2018 DOI: 10.1029/2018JA025654 |
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Determining solar wind and geomagnetic activity parameters most favorable to strong electron flux enhancements is an important step towards forecasting radiation belt dynamics. Using electron flux measurements from Global Positioning System satellites at L = 4.2 in 2009-2016, we seek statistical relationships between flux enhancements at different energies and solar wind dynamic pressure Pdyn, AE, and Kp, from hundreds of events inside and outside the plasmasphere. Most ⩾1 MeV electron flux enhancements occur during non-st ... Zhang, X.-J.; Mourenas, D.; Artemyev, A.; Angelopoulos, V.; Thorne, R.; Published by: Journal of Geophysical Research: Space Physics Published on: 06/2018 YEAR: 2018 DOI: 10.1029/2018JA025497 chorus waves; Electron energization; Electron flux enhancements; GPS satellites; Radiation belt; Solar wind and geomagnetic activities; Van Allen Probes |
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We use 3 years of Van Allen Probes observations of highly oblique lower-band chorus waves at low latitudes over L = 4\textendash6 to provide a comprehensive statistics of the distribution of their magnetic and electric powers and full energy density as a function of wave refractive index N, L shell, and geomagnetic activity AE. We use the refractive index calculated either in the cold plasma approximation or in the quasi-electrostatic (hot plasma) approximation and either observed wave electric fields or corrected wave elect ... Shi, R.; Mourenas, D.; Artemyev, A.; Li, W.; Ma, Q.; Published by: Journal of Geophysical Research: Space Physics Published on: 06/2018 YEAR: 2018 DOI: 10.1029/2018JA025337 |
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Plasma anisotropies and currents in the near-Earth plasma sheet and inner magnetosphere The region occupying radial distances of \~3 - 9 Earth radii (RE) in the night side, includes the near-Earth plasma sheet with stretched magnetic field lines and the inner magnetosphere with strong dipolar magnetic field. In this region, the plasma flow energy, which was injected into the inner magnetosphere from the magnetotail, is converted to particle heating and electromagnetic wave generation. These important processes are controlled by plasma anisotropies, which are the focus of this study. Using measurements of THEMIS ... Artemyev, A.; Zhang, X.-J.; Angelopoulos, V.; Runov, A.; Spence, H.; Larsen, B.; Published by: Journal of Geophysical Research: Space Physics Published on: 06/2018 YEAR: 2018 DOI: 10.1029/2018JA025232 injections; inner magnetosphere; plasma currents; plasma sheet; Van Allen Probes |
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Resonant interactions between electrons and chorus waves are responsible for a wide range of phenomena in near-Earth space (e.g., diffuse aurora, acceleration of MeV electrons, etc.). Although quasi-linear diffusion is believed to be the primary paradigm for describing such interactions, an increasing number of investigations suggest that nonlinear effects are also important in controlling the rapid dynamics of electrons. However, present models of nonlinear wave-particle interactions, which have been successfully used to de ... Zhang, X.-J.; Thorne, R.; Artemyev, A.; Mourenas, D.; Angelopoulos, V.; Bortnik, J.; Kletzing, C.; Kurth, W.; Hospodarsky, G.; Published by: Journal of Geophysical Research: Space Physics Published on: 06/2018 YEAR: 2018 DOI: 10.1029/2018JA025390 chorus waves; Effective amplitude; nonlinear wave-particle interaction; spatial distribution; statistics; Van Allen Probes; Wave-packet length |
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Electron nonlinear resonant interaction with short and intense parallel chorus wave-packets One of the major drivers of radiation belt dynamics, electron resonant interaction with whistler-mode chorus waves, is traditionally described using the quasi-linear diffusion approximation. Such a description satisfactorily explains many observed phenomena, but its applicability can be justified only for sufficiently low intensity, long duration waves. Recent spacecraft observations of a large number of very intense lower band chorus waves (with magnetic field amplitudes sometimes reaching \~1\% of the background) therefore ... Mourenas, D.; Zhang, X.-J.; Artemyev, A.; Angelopoulos, V.; Thorne, R.; Bortnik, J.; Neishtadt, A.; Vasiliev, A.; Published by: Journal of Geophysical Research: Space Physics Published on: 05/2018 YEAR: 2018 DOI: 10.1029/2018JA025417 chorus waves; ; kinetic equation; nonlinear interaction; Radiation belts; short wave-packets; trapping; Van Allen Probes |
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Whistler mode chorus waves are particularly important in outer radiation belt dynamics due to their key role in controlling the acceleration and scattering of electrons over a very wide energy range. The efficiency of wave-particle resonant interactions is defined by whistler wave properties which have been described by the approximation of plane linear waves propagating through the cold plasma of the inner magnetosphere. However, recent observations of extremely high-amplitude whistlers suggest the importance of nonlinear w ... Agapitov, O.; Drake, J.; Vasko, I.; Mozer, F.; Artemyev, A.; Krasnoselskikh, V.; Angelopoulos, V.; Wygant, J.; Reeves, G.; Published by: Geophysical Research Letters Published on: 03/2018 YEAR: 2018 DOI: 10.1002/2017GL076957 Electron acceleration; electron acoustic waves; induced scattering; nonlinear wave-particle interactions; Van Allen Probes; wave steepening; Whistler waves |
| 2017 |
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Synthetic empirical chorus wave model from combined Van Allen Probes and Cluster statistics Chorus waves are among the most important natural electromagnetic emissions in the magnetosphere as regards their potential effects on electron dynamics. They can efficiently accelerate or precipitate electrons trapped in the outer radiation belt, producing either fast increases of relativistic particle fluxes, or auroras at high latitudes. Accurately modeling their effects, however, requires detailed models of their wave power and obliquity distribution as a function of geomagnetic activity in a particularly wide spatial do ... Agapitov, O.; Mourenas, D.; Artemyev, A.; Mozer, F.; Hospodarsky, G.; Bonnell, J.; Krasnoselskikh, V.; Published by: Journal of Geophysical Research: Space Physics Published on: 12/2017 YEAR: 2017 DOI: 10.1002/2017JA024843 |
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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\textendash100 eV) electrons. A combined investigation of wave and electron distribution characteristics o ... Ma, Q.; Artemyev, A.; Mourenas, D.; Li, W.; Thorne, R.; Kletzing, C.; Kurth, W.; Hospodarsky, G.; Reeves, G.; Spence, H.; Wygant, J.; Published by: Geophysical Research Letters Published on: 12/2017 YEAR: 2017 DOI: 10.1002/2017GL075892 Landau damping; maximum refractive index; oblique chorus waves; thermal electron effects; Van Allen Probes; Van Allen Probes observation |
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Contemporaneous EMIC and Whistler-Mode Waves: Observations and Consequences for MeV Electron Loss The high variability of relativistic (MeV) electron fluxes in the Earth\textquoterights radiation belts is partly controlled by loss processes involving resonant interactions with electromagnetic ion cyclotron (EMIC) and whistler-mode waves. But as previous statistical models were generated independently for each wave mode, whether simultaneous electron scattering by the two wave types has global importance remains an open question. Using >3 years of simultaneous Van Allen Probes and THEMIS measurements, we explore the conte ... Zhang, X.-J.; Mourenas, D.; Artemyev, A.; Angelopoulos, V.; Thorne, R.; Published by: Geophysical Research Letters Published on: 07/2017 YEAR: 2017 DOI: 10.1002/2017GL073886 electron lifetime; EMIC waves; Rediation belts; relativistic electron loss; Van Allen Probes; wave particle interaction; WHISTLER-MODE WAVES |
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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, an ... Ma, Qianli; Mourenas, Didier; Li, Wen; Artemyev, Anton; Thorne, Richard; Published by: Geophysical Research Letters Published on: 06/2017 YEAR: 2017 DOI: 10.1002/2017GL073885 Electron scattering; Statistical wave model; Van Allen Probes; Van Allen Probes observation; VLF waves |
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Electron-acoustic solitons and double layers in the inner magnetosphere The Van Allen Probes observe generally two types of electrostatic solitary waves (ESW) contributing to the broadband electrostatic wave activity in the nightside inner magnetosphere. ESW with symmetric bipolar parallel electric field are electron phase space holes. The nature of ESW with asymmetric bipolar (and almost unipolar) parallel electric field has remained puzzling. To address their nature, we consider a particular event observed by Van Allen Probes to argue that during the broadband wave activity electrons with ener ... Vasko, I; Agapitov, O.; Mozer, F.; Bonnell, J.; Artemyev, A.; Krasnoselskikh, V.; Reeves, G.; Hospodarsky, G.; Published by: Geophysical Research Letters Published on: 05/2017 YEAR: 2017 DOI: 10.1002/2017GL074026 double layers; electron-acoustic waves; inner magnetosphere; solitons; Van Allen Probes |
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Diffusive scattering of electrons by electron holes around injection fronts Van Allen Probes have detected nonlinear electrostatic spikes around injection fronts in the outer radiation belt. These spikes include electron holes (EH), double layers, and more complicated solitary waves. We show that EHs can efficiently scatter electrons due to their substantial transverse electric fields. Although the electron scattering driven by EHs is diffusive, it cannot be evaluated via the standard quasi-linear theory. We derive analytical formulas describing local electron scattering by a single EH and verify th ... Vasko, I; Agapitov, O.; Mozer, F.; Artemyev, A.; Krasnoselskikh, V.; Bonnell, J.; Published by: Journal of Geophysical Research: Space Physics Published on: 03/2017 YEAR: 2017 DOI: 10.1002/2016JA023337 electron holes; electron losses; injection; Radiation belt; solitary waves; Van Allen Probes |
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Transverse eV ion heating by random electric field fluctuations in the plasmasphere Charged particle acceleration in the Earth inner magnetosphere is believed to be mainly due to the local resonant wave-particle interaction or particle transport processes. However, the Van Allen Probes have recently provided interesting evidence of a relatively slow transverse heating of eV ions at distances about 2\textendash3 Earth radii during quiet times. Waves that are able to resonantly interact with such very cold ions are generally rare in this region of space, called the plasmasphere. Thus, non-resonant wave-partic ... Artemyev, A.; Mourenas, D.; Agapitov, O.; Blum, L.; Published by: Physics of Plasmas Published on: 02/2017 YEAR: 2017 DOI: 10.1063/1.4976713 electric fields; Electrostatic Waves; protons; Van Allen Probes; Wave power; Whistler waves |
| 2016 |
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Electron holes in the outer radiation belt: Characteristics and their role in electron energization Van Allen Probes have detected electron holes (EHs) around injection fronts in the outer radiation belt. Presumably generated near equator, EHs propagate to higher latitudes potentially resulting in energization of electrons trapped within EHs. This process has been recently shown to provide electrons with energies up to several tens of keV and requires EH propagation up to rather high latitudes. We have analyzed more than 100 EHs observed around a particular injection to determine their kinetic structure and potential energ ... Vasko, I; Agapitov, O.; Mozer, F.; Artemyev, A.; Drake, J.; Kuzichev, I.; Published by: Journal of Geophysical Research: Space Physics Published on: 12/2016 YEAR: 2016 DOI: 10.1002/2016JA023083 Electron acceleration; electron holes; injection; Radiation belt; solitary waves; Van Allen Probes |
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Unraveling the excitation mechanisms of highly oblique lower band chorus waves Excitation mechanisms of highly oblique, quasi-electrostatic lower band chorus waves are investigated using Van Allen Probes observations near the equator of the Earth\textquoterights magnetosphere. Linear growth rates are evaluated based on in situ, measured electron velocity distributions and plasma conditions and compared with simultaneously observed wave frequency spectra and wave normal angles. Accordingly, two distinct excitation mechanisms of highly oblique lower band chorus have been clearly identified for the first ... Li, W.; Mourenas, D.; Artemyev, A.; Bortnik, J.; Thorne, R.; Kletzing, C.; Kurth, W.; Hospodarsky, G.; Reeves, G.; Funsten, H.; Spence, H.; Published by: Geophysical Research Letters Published on: 09/2016 YEAR: 2016 DOI: 10.1002/grl.v43.1710.1002/2016GL070386 beam instability; lower band chorus; oblique chorus excitation; temperature anisotropy; Van Allen Probes |
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We present multipoint observations of earthward moving dipolarization fronts and energetic particle injections from NASA\textquoterights Magnetospheric Multiscale mission with a focus on electron acceleration. From a case study during a substorm on 02 August 2015, we find that electrons are only accelerated over a finite energy range, from a lower energy threshold at ~7\textendash9 keV up to an upper energy cutoff in the hundreds of keV range. At energies lower than the threshold energy, electron fluxes decrease, potentially ... Turner, D.; Fennell, J.; Blake, J.; Clemmons, J.; Mauk, B.; Cohen, I.; Jaynes, A.; Craft, J.; Wilder, F.; Baker, D.; Reeves, G.; Gershman, D.; Avanov, L.; Dorelli, J.; Giles, B.; Pollock, C.; Schmid, D.; Nakamura, R.; Strangeway, R.; Russell, C.; Artemyev, A.; Runov, A.; Angelopoulos, V.; Spence, H.; Torbert, R.; Burch, J.; Published by: Geophysical Research Letters Published on: 08/2016 YEAR: 2016 DOI: 10.1002/2016GL069691 energetic particle injections; magnetotail; Particle acceleration; plasma sheet; reconnection; substorm; Van Allen Probes |
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In this paper we review recent spacecraft observations of oblique whistler-mode waves in the Earth\textquoterights inner magnetosphere as well as the various consequences of the presence of such waves for electron scattering and acceleration. In particular, we survey the statistics of occurrences and intensity of oblique chorus waves in the region of the outer radiation belt, comprised between the plasmapause and geostationary orbit, and discuss how their actual distribution may be explained by a combination of linear and no ... Artemyev, Anton; Agapitov, Oleksiy; Mourenas, Didier; Krasnoselskikh, Vladimir; Shastun, Vitalii; Mozer, Forrest; Published by: Space Science Reviews Published on: 04/2016 YEAR: 2016 DOI: 10.1007/s11214-016-0252-5 Earth radiation belts; Van Allen Probes; Wave-particle interaction; Whistler waves |
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Near-Relativistic Electron Acceleration by Landau Trapping in Time Domain Structures Data from the Van Allen Probes have provided the first extensive evidence of nonlinear (as opposed to quasi-linear) wave-particle interactions in space with the associated rapid (less than a bounce period) electron acceleration to hundreds of keV by Landau resonance in the parallel electric field of time domain structures (TDSs) traveling at high speeds (~20,000 km/s). This observational evidence is supported by simulations and discussion of the source and spatial extent of the fast TDS. This result indicates the possibility ... Mozer, F.; Artemyev, A.; Agapitov, O.; Mourenas, D.; Vasko, I.; Published by: Geophysical Research Letters Published on: 01/2016 YEAR: 2016 DOI: 10.1002/2015GL067316 |
| 2015 |
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Simultaneous observations of electron velocity distributions and chorus waves by the Van Allen Probe B are analyzed to identify long-lasting (more than 6 h) signatures of electron Landau resonant interactions with oblique chorus waves in the outer radiation belt. Such Landau resonant interactions result in the trapping of \~1\textendash10 keV electrons and their acceleration up to 100\textendash300 keV. This kind of process becomes important for oblique whistler mode waves having a significant electric field component along ... Agapitov, O.; Artemyev, A.; Mourenas, D.; Mozer, F.; Krasnoselskikh, V.; Published by: Geophysical Research Letters Published on: 12/2015 YEAR: 2015 DOI: 10.1002/2015GL066887 Landau resonance; nonlinear acceleration of electrons; oblique whistlers; Radiation belts; seed population; Van Allen Probes |
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Wave-particle interactions in the outer radiation belts Data from the Van Allen Probes have provided the first extensive evidence of non-linear (as opposed to quasi-linear) wave-particle interactions in space, with the associated rapid (fraction of a bounce period) electron acceleration, to hundreds of keV by Landau resonance, in the parallel electric fields of time domain structures (TDS) and very oblique chorus waves. The experimental evidence, simulations, and theories of these processes are discussed. Agapitov, O.~V.; Mozer, F.~S.; Artemyev, A.~V.; Mourenas, D.; Krasnoselskikh, V.~V.; Published by: Advances in Astronomy and Space Physics Published on: 12/2015 plasma waves and instabilities; Radiation belts; Van Allen Probes; Wave-particle interaction |
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Empirical model of lower band chorus wave distribution in the outer radiation belt Accurate modeling of wave-particle interactions in the radiation belts requires detailed information on wave amplitudes and wave-normal angular distributions over L shells, magnetic latitudes, magnetic local times, and for various geomagnetic activity conditions. In this work, we develop a new and comprehensive parametric model of VLF chorus waves amplitudes and obliqueness in the outer radiation belt using statistics of VLF measurements performed in the chorus frequency range during 10 years (2001\textendash2010) aboard the ... Agapitov, O.; Artemyev, A.; Mourenas, D.; Mozer, F.; Krasnoselskikh, V.; Published by: Journal of Geophysical Research: Space Physics Published on: 12/2015 YEAR: 2015 DOI: 10.1002/2015JA021829 |
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Van Allen Probes observations in the outer radiation belt have demonstrated an abundance of electrostatic electron-acoustic double layers (DL). DLs are frequently accompanied by field-aligned (bidirectional) pitch angle distributions (PAD) of electrons with energies from hundred eVs up to several keV. We perform numerical simulations of the DL interaction with thermal electrons making use of the test particle approach. DL parameters assumed in the simulations are adopted from observations. We show that DLs accelerate thermal ... Vasko, I; Agapitov, O.; Mozer, F.; Artemyev, A.; Published by: Journal of Geophysical Research: Space Physics Published on: 10/2015 YEAR: 2015 DOI: 10.1002/2015JA021644 double layers; Fermi mechanism; field-aligned pitch angle distributions; outer radiation belt; thermal electron acceleration; Van Allen Probes |
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In the present paper, we investigate the trapping of relativistic electrons by intense whistler-mode waves or electromagnetic ion cyclotron waves in the Earth\textquoterights radiation belts. We consider the non-resonant impact of additional, lower amplitude magnetic field fluctuations on the stability of electron trapping. We show that such additional non-resonant fluctuations can break the adiabatic invariant corresponding to trapped electron oscillations in the effective wave potential. This destruction results in a diffu ... Artemyev, A.; Mourenas, D.; Agapitov, O.; Vainchtein, D.; Mozer, F.; Krasnoselskikh, V.; Published by: Physics of Plasmas Published on: 08/2015 YEAR: 2015 DOI: 10.1063/1.4927774 Cyclotron resonances; magnetic fields; Particle fluctuations; Plasma electromagnetic waves; Whistler waves |
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Modeling the spatio-temporal evolution of relativistic electron fluxes trapped in the Earth\textquoterights radiation belts in the presence of radial diffusion coupled with wave-induced losses should address one important question: how deep can relativistic electrons penetrate into the inner magnetosphere? However, a full modelling requires extensive numerical simulations solving the comprehensive quasi-linear equations describing pitch-angle and radial diffusion of the electron distribution, making it rather difficult to pe ... Mourenas, D.; Artemyev, A.; Agapitov, O.V.; Published by: Journal of Geophysical Research: Space Physics Published on: 08/2015 YEAR: 2015 DOI: 10.1002/2015JA021623 inner belt; Keywords: radial diffusion; Radiation belts; Van Allen Probes |
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In this paper, we study relativistic electron scattering by fast magnetosonic waves. We compare results of test particle simulations and the quasi-linear theory for different spectra of waves to investigate how a fine structure of the wave emission can influence electron resonant scattering. We show that for a realistically wide distribution of wave normal angles theta (i.e., when the dispersion delta theta >= 0.5 degrees), relativistic electron scattering is similar for a wide wave spectrum and for a spectrum consisting in ... Artemyev, A.; Mourenas, D.; Agapitov, O.; Krasnoselskikh, V.; Published by: Physics of Plasmas Published on: 06/2015 YEAR: 2015 DOI: 10.1063/1.4922061 chorus waves; CLUSTER SPACECRAFT; equatorial noise; MAGNETIC-FIELD; PLASMA; Quasi-linear diffusion; radiation belt electrons; RESONANT SCATTERING; Van Allen Probes; WHISTLER-MODE WAVES |
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Huge numbers of different non-linear structures (double layers, electron holes, non-linear whistlers, etc. referred to as Time Domain Structures - TDS) have been observed by the electric field experiment on the Van Allen Probes. Some of them are associated with whistler waves. Such TDS often emerge on the forward edges of the whistler wave packets and form chains. The parametric decay of a whistler wave into a whistler wave propagating in the opposite direction and an electron acoustic wave is studied experimentally as well ... Agapitov, O.; Krasnoselskikh, V.; Mozer, F.; Artemyev, A.; Volokitin, A.; Published by: Geophysical Research Letters Published on: 05/2015 YEAR: 2015 DOI: 10.1002/2015GL064145 electron acoustic waves; nonlinear structure formation; parametric decay of whistlers; Van Allen Probes |
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Wave energy budget analysis in the Earth\textquoterights radiation belts uncovers a missing energy Whistler-mode emissions are important electromagnetic waves pervasive in the Earth\textquoterights magnetosphere, where they continuously remove or energize electrons trapped by the geomagnetic field, controlling radiation hazards to satellites and astronauts and the upper-atmosphere ionization or chemical composition. Here, we report an analysis of 10-year Cluster data, statistically evaluating the full wave energy budget in the Earth\textquoterights magnetosphere, revealing that a significant fraction of the energy corresp ... Artemyev, A.V.; Agapitov, O.V.; Mourenas, D.; Krasnoselskikh, V.V.; Mozer, F.S.; Published by: Nature Communications Published on: 05/2015 YEAR: 2015 DOI: 10.1038/ncomms8143 Astronomy; Fluids and plasma physics; Physical sciences; Planetary sciences |
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Acceleration of ions by electric field pulses in the inner magnetosphere 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 te ... Artemyev, A.V.; Liu, J.; Angelopoulos, V.; Runov, A.; Published by: Journal of Geophysical Research: Space Physics Published on: 05/2015 YEAR: 2015 DOI: 10.1002/2015JA021160 |
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In this paper we investigate the scattering of relativistic electrons in the night-side outer radiation belt (around the geostationary orbit). We consider the particular case of low geomagnetic activity (|Dst|< 20 nT), quiet conditions in the solar wind, and absence of whistler wave emissions. For such conditions we find several events of Van-Allen probe observations of butterfly pitch-angle distributions of relativistic electrons (energies about 1-3 MeV). Many previous publications have described such pitch-angle distributi ... Artemyev, A.; Agapitov, O.; Mozer, F.; Spence, H.; Published by: Journal of Geophysical Research: Space Physics Published on: 05/2015 YEAR: 2015 DOI: 10.1002/2014JA020865 butterfly distribution; Electron scattering; nonadiabatic dynamics; Radiation belts; Van Allen Probes |
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Magnetic field depression within electron holes We analyze electron holes that are spikes of the electrostatic field (up to 500 mV/m) observed by Van Allen Probes in the outer radiation belt. The unexpected feature is the magnetic field depression of about several tens of picotesla within many of the spikes. The earlier observations showed amplification or negligible perturbations of the magnetic field within the electron holes. We suggest that the observed magnetic field depression is due to the diamagnetic current of hot and highly anisotropic population of electrons tr ... Vasko, I; Agapitov, O.; Mozer, F.; Artemyev, A.; Jovanovic, D.; Published by: Geophysical Research Letters Published on: 04/2015 YEAR: 2015 DOI: 10.1002/2015GL063370 diamagnetic effect; electron hole; outer radiation belt; Van Allen Probes |
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Time Domain Structures: what and where they are, what they do, and how they are made Time Domain Structures (TDS) (electrostatic or electromagnetic electron holes, solitary waves, double layers, etc.) are >=1 msec pulses having significant parallel (to the background magnetic field) electric fields. They are abundant through space and occur in packets of hundreds in the outer Van Allen radiation belts where they produce magnetic-field-aligned electron pitch angle distributions at energies up to a hundred keV. TDS can provide the seed electrons that are later accelerated to relativistic energies by whistlers ... Mozer, F.S.; Agapitov, O.V.; Artemyev, A.; Drake, J.F.; Krasnoselskikh, V.; Lejosne, S.; Vasko, I.; Published by: Geophysical Research Letters Published on: 04/2015 YEAR: 2015 DOI: 10.1002/2015GL063946 |
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Very Oblique Whistler Generation By Low Energy Electron Streams Whistler-mode chorus waves are present throughout the Earth\textquoterights outer radiation belt as well as at larger distances from our planet. While the generation mechanisms of parallel lower-band chorus waves and oblique upper-band chorus waves have been identified and checked in various instances, the statistically significant presence in recent satellite observations of very oblique lower-band chorus waves near the resonance cone angle remains to be explained. Here we discuss two possible generation mechanisms for such ... Mourenas, D.; Artemyev, A.; Agapitov, O.; Krasnoselskikh, V.; Mozer, F.S.; Published by: Journal of Geophysical Research: Space Physics Published on: 04/2015 YEAR: 2015 DOI: 10.1002/2015JA021135 Chorus wave; Cyclotron resonance; Landau resonance; oblique whistler; wave generation |
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Field-aligned chorus wave spectral power in Earth\textquoterights outer radiation belt Chorus-type whistler waves are one of the most intense electromagnetic waves generated naturally in the magnetosphere. These waves have a substantial impact on the radiation belt dynamics as they are thought to contribute to electron acceleration and losses into the ionosphere through resonant wave\textendashparticle interaction. Our study is devoted to the determination of chorus wave power distribution on frequency in a wide range of magnetic latitudes, from 0 to 40\textdegree. We use 10 years of magnetic and electric fiel ... Breuillard, H.; Agapitov, O.; Artemyev, A.; Kronberg, E.; Haaland, S.; Daly, P.; Krasnoselskikh, V.; Boscher, D.; Bourdarie, S.; Zaliznyak, Y.; Rolland, G.; Published by: Annales Geophysicae Published on: 01/2015 YEAR: 2015 DOI: 10.5194/angeo-33-583-2015 |
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The distribution of trapped energetic electrons inside the Earth\textquoterights 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 appro ... Mourenas, D.; Artemyev, A.; Agapitov, O.V.; Krasnoselskikh, V.; Li, W.; Published by: Journal of Geophysical Research: Space Physics Published on: 11/2014 YEAR: 2014 DOI: 10.1002/2014JA020443 electron distribution; pitch-angle distribution; Radiation belt |
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Wave normal distributions of lower-band whistler-mode waves observed outside the plasmapause exhibit two peaks; one near the parallel direction and the other at very oblique angles. We analyze a number of conjunction events between the Van Allen Probes near the equatorial plane and POES satellites at conjugate low altitudes, where lower-band whistler-mode wave amplitudes were inferred from the two-directional POES electron measurements over 30\textendash100 keV, assuming that these waves were quasi-parallel. For conjunction ... Li, W.; Mourenas, D.; Artemyev, A.; Agapitov, O.; Bortnik, J.; Albert, J.; Thorne, R.; Ni, B.; Kletzing, C.; Kurth, W.; Hospodarsky, G.; Published by: Geophysical Research Letters Published on: 08/2014 YEAR: 2014 DOI: 10.1002/2014GL061260 chorus waves; electron precipitation; oblique whistler; pitch angle scattering |
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Fast transport of resonant electrons in phase space due to nonlinear trapping by whistler waves We present an analytical, simplified formulation accounting for the fast transport of relativistic electrons in phase space due to wave-particle resonant interactions in the inhomogeneous magnetic field of Earth\textquoterights radiation belts. We show that the usual description of the evolution of the particle velocity distribution based on the Fokker-Planck equation can be modified to incorporate nonlinear processes of wave-particle interaction, including particle trapping. Such a modification consists in one additional op ... Artemyev, A.; Vasiliev, A.; Mourenas, D.; Agapitov, O.; Krasnoselskikh, V.; Boscher, D.; Rolland, G.; Published by: Geophysical Research Letters Published on: 08/2014 YEAR: 2014 DOI: 10.1002/grl.v41.1610.1002/2014GL061380 particle trapping; Radiation belts; Wave-particle interaction |
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Thermal electron acceleration by localized bursts of electric field in the radiation belts In this paper we investigate the resonant interaction of thermal ~10-100 eV electrons with a burst of electrostatic field that results in electron acceleration to kilovolt energies. This single burst contains a large parallel electric field of one sign and a much smaller, longer lasting parallel field of the opposite sign. The Van Allen Probe spacecraft often observes clusters of spatially localized bursts in the Earth\textquoterights outer radiation belts. These structures propagate mostly away from thegeomagnetic equator a ... Artemyev, A.; Agapitov, O.; Mozer, F.; Krasnoselskikh, V.; Published by: Geophysical Research Letters Published on: 08/2014 YEAR: 2014 DOI: 10.1002/2014GL061248 Radiation belts; thermal electrons; Van Allen Probes; Wave-particle interaction |
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