Biblio

Found 27 results
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2019
Authors: Lejosne Solène, and Mozer F S
Title: Shorting Factor In‐Flight Calibration for the Van Allen Probes DC Electric Field Measurements in the Earth's Plasmasphere
Abstract: Satellite‐based direct electric field measurements deliver crucial information for space science studies. Yet they require meticulous design and calibration. In‐flight calibration of double‐probe instruments is usually presented in the most common case of tenuous plasmas, where the presence of an electrostatic structure surrounding the charged spacecraft alters the geophysical electric field measurements. To account for this effect and the uncertainty in the boom length, the measured electric field is multiplied by a parameter called the shorting factor (sf). In the plasmasphere, the Debye length is very small in comparison with spacecraft dimension, and there is no shorting of the electric field measurements (sf = 1). However, the electric field induced by spacecraft motion greatly . . .
Date: 04/2019 Publisher: Earth and Space Science Pages: 646 - 654 DOI: 10.1029/2018EA000550 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018EA000550
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2018
Authors: Lejosne ène, Kunduri B. S. R., Mozer F S, and Turner D. L.
Title: Energetic electron injections deep into the inner magnetosphere: a result of the subauroral polarization stream (SAPS) potential drop
Abstract: It has been reported that the dynamics of energetic (tens to hundreds of keV) electrons and ions is inconsistent with the theoretical picture in which the large‐scale electric field is a superposition of corotation and convection electric fields. Combining one year of measurements by the Super Dual Auroral Radar Network, DMSP F‐18 and the Van Allen Probes, we show that subauroral polarization streams are observed when energetic electrons have penetrated below L = 4. Outside the plasmasphere in the premidnight region, potential energy is subtracted from the total energy of ions and added to the total energy of electrons during SAPS onset. This potential energy is converted into radial motion as the energetic particles drift around Earth and leave the SAPS azimuthal sector. As a result, . . .
Date: 04/2018 Publisher: Geophysical Research Letters DOI: 10.1029/2018GL077969 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL077969
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Authors: Lejosne ène, and Mozer F S
Title: Magnetic activity dependence of the electric drift below L=3
Abstract: More than two years of magnetic and electric field measurements by the Van Allen Probes are analyzed with the objective of determining the average effects of magnetic activity on the electric drift below L=3. The study finds that an increase in magnetospheric convection leads to a decrease in the magnitude of the azimuthal component of the electric drift, especially in the night‐side. The amplitude of the slowdown is a function of L, local time MLT, and Kp, in a pattern consistent with the storm‐time dynamics of the ionosphere and thermosphere. To a lesser extent, magnetic activity also alters the average radial component of the electric drift below L=3. A global picture for the average variations of the electric drift with Kp is provided as a function of L and MLT. It is the first tim. . .
Date: 04/2018 Publisher: Geophysical Research Letters DOI: 10.1029/2018GL077873 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL077873
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Authors: Agapitov O., Drake J. F., Vasko I., Mozer F S, Artemyev A., et al.
Title: Nonlinear Electrostatic Steepening of Whistler Waves: The Guiding Factors and Dynamics in Inhomogeneous Systems
Abstract: 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 wave‐particle interactions for the dynamics of the outer radiation belt. Oblique chorus waves observed in the inner magnetosphere often exhibit drastically nonsinusoidal (with significant power in the higher harmonics) waveforms of the parallel electric field, pres. . .
Date: 03/2018 Publisher: Geophysical Research Letters DOI: 10.1002/2017GL076957 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2017GL076957
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Authors: Mozer F S, Hull A., Lejosne S., and Vasko I. Y.
Title: Reply to Comment by Nishimura Et Al.
Abstract: Nishimura et al. (2010, https://doi.org/10.1126/science.1193186, 2011, https://doi.org/10.1029/2011JA016876, 2013, https://doi.org/10.1029/2012JA018242, and in their comment, hereafter called N18) have suggested that chorus waves interact with equatorial electrons to produce pulsating auroras. We agree that chorus can scatter electrons >10 keV, as do Time Domain Structures (TDSs). Lower‐energy electrons occurring in pulsating auroras cannot be produced by chorus, but such electrons are scattered and accelerated by TDS. TDSs often occur with chorus and have power in their spectra at chorus frequencies. Thus, the absence of power at low frequencies is not evidence that TDSs are absent, as an example shows. Through examination of equatorial electric field waveforms and electron pitch angle . . .
Date: 03/2018 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2018JA025218 Available at: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2018JA025218
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2017
Authors: Agapitov O., Blum L. W., Mozer F S, Bonnell J. W., and Wygant J
Title: Chorus whistler wave source scales as determined from multipoint Van Allen Probe measurements
Abstract: 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 key parameters for both nonlinear and quasi-linear treatment of wave-particle interactions are the temporal and spatial scales of the wave source region and coherence of the wave field perturbations. Neither the source scale nor the coherence scale is well established experimentally, mostly because of a lack of multipoint VLF waveform measurements. We present an unprecedentedly long interval of coordinated VLF waveform measurements (sampled at 16384 s−1) aboard the two Van Allen Probes spacecraft—9 h (0800–1200 UT and 1700–2200 UT) during two consecutive apogees on 15 July . . .
Date: 03/2017 Publisher: Geophysical Research Letters DOI: 10.1002/2017GL072701 Available at: http://doi.wiley.com/10.1002/2017GL072701
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Authors: Vasko I. Y., Agapitov O. V., Mozer F S, Artemyev A. V., Krasnoselskikh V. V., et al.
Title: Diffusive scattering of electrons by electron holes around injection fronts
Abstract: 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 them via test particle simulations. We show that the most efficiently scattered are gyroresonant electrons (crossing EH on a time scale comparable to the local electron gyroperiod). We compute bounce-averaged diffusion coefficients and demonstrate their dependence on the . . .
Date: 03/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023337 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA023337/full
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Authors: Vasko I. Y., Agapitov O. V., Mozer F S, Bonnell J. W., Artemyev A. V., et al.
Title: Electron-acoustic solitons and double layers in the inner magnetosphere
Abstract: 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 energy above 200 eV provide the dominant contribution to the total electron density, while the density of cold electrons (below a few eV) is less than a few tenths of the total electron density. We show that velocities of the asymmetric ESW are close to velocity of electron. . .
Date: 05/2017 Publisher: Geophysical Research Letters DOI: 10.1002/2017GL074026 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017GL074026/full
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Authors: Lejosne ène, Maus Stefan, and Mozer F S
Title: Model-observation comparison for the geographic variability of the plasma electric drift in the Earth's innermost magnetosphere
Abstract: Plasmaspheric rotation is known to lag behind Earth rotation. The causes for this corotation lag are not yet fully understood. We have used more than two years of Van Allen Probe observations to compare the electric drift measured below L~2 with the predictions of a general model. In the first step, a rigid corotation of the ionosphere with the solid Earth was assumed in the model. The results of the model-observation comparison are twofold: (1) radially, the model explains the average observed geographic variability of the electric drift; (2) azimuthally, the model fails to explain the full amplitude of the observed corotation lag. In the second step, ionospheric corotation was modulated in the model by thermospheric winds, as given by the latest version of the Horizontal Wind Model (HWM1. . .
Date: 07/2017 Publisher: Geophysical Research Letters DOI: 10.1002/2017GL074862 Available at: onlinelibrary.wiley.com/doi/10.1002/2017GL074862/full
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Authors: Mozer F S, Agapitov O. V., Hull A., Lejosne S., and Vasko I. Y.
Title: Pulsating auroras produced by interactions of electrons and time domain structures
Abstract: Previous evidence has suggested that either lower band chorus waves or kinetic Alfven waves scatter equatorial kilovolt electrons that propagate to lower altitudes where they precipitate or undergo further low-altitude scattering to make pulsating auroras. Recently, time domain structures (TDSs) were shown, both theoretically and experimentally, to efficiently scatter equatorial electrons. To assess the relative importance of these three mechanisms for production of pulsating auroras, 11 intervals of equatorial THEMIS data and a 4 h interval of Van Allen Probe measurements have been analyzed. During these events, lower band chorus waves produced only negligible modifications of the equatorial electron distributions. During the several TDS events, the equatorial 0.1–3 keV electrons became. . .
Date: 08/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024223 Available at: onlinelibrary.wiley.com/doi/10.1002/2017JA024223/full
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Authors: Mozer F S, Agapitov O. V., Blake J B, and Vasko I. Y.
Title: SIMULTANEOUS OBSERVATIONS OF LOWER BAND CHORUS EMISSIONS AT THE EQUATOR AND MICROBURST PRECIPITATING ELECTRONS IN THE IONOSPHERE
Abstract: On December 11, 2016 at 00:12:30 UT, Van Allen Probe-B, at the equator and near midnight, and AC6-B, in the ionosphere, were on magnetic field lines whose 100 km altitude foot points were separated by 600 km. Van Allen Probe-B observed a 30 second burst of lower band chorus waves (with maximum amplitudes >1 nT) at the same time that AC6-B observed intense microburst electrons in the loss cone. One-second averaged variations of the chorus intensity and the microburst electron flux were well-correlated. The low altitude electron flux expected from quasi-linear diffusion of the equatorial electrons by the equatorial chorus is in excellent agreement with the observed, one second averaged, low altitude electron flux. However the large amplitude, <0.5 second duration, low altitude electron pulse. . .
Date: 12/2017 Publisher: Geophysical Research Letters DOI: 10.1002/2017GL076120 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017GL076120/full
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Authors: Lejosne ène, and Mozer F S
Title: Sub-Auroral Polarization Stream (SAPS) duration as determined from Van Allen Probe successive electric drift measurements
Abstract: We examine a characteristic feature of the magnetosphere-ionosphere coupling, namely, the persistent and latitudinally narrow bands of rapid westward ion drifts called the Sub-Auroral Polarization Streams (SAPS). Despite countless works on SAPS, information relative to their durations is lacking. Here, we report on the first statistical analysis of more than 200 near-equatorial SAPS observations based on more than two years of Van Allen Probe electric drift measurements. First, we present results relative to SAPS radial locations and amplitudes. Then, we introduce two different ways to estimate SAPS durations. In both cases, SAPS activity is estimated to last for about nine hours on average. However, our estimates for SAPS duration are limited either by the relatively long orbital periods . . .
Date: 08/2017 Publisher: Geophysical Research Letters DOI: 10.1002/2017GL074985 Available at: http://http://onlinelibrary.wiley.com/doi/10.1002/2017GL074985/full
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Authors: Agapitov O. V., Mourenas D., Artemyev A. V., Mozer F S, Hospodarsky G., et al.
Title: Synthetic empirical chorus wave model from combined Van Allen Probes and Cluster statistics
Abstract: 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 domain, rarely available based solely on the statistics obtained from only one satellite mission. Here, we seize the opportunity of synthesizing data from the Van Allen Probes and Cluster spacecraft to provide a new comprehensive chorus wave model in the outer radiation b. . .
Date: 12/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024843 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA024843/full
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2016
Authors: Vasko I. Y., Agapitov O. V., Mozer F S, Artemyev A. V., Drake J. F., et al.
Title: Electron holes in the outer radiation belt: Characteristics and their role in electron energization
Abstract: 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 energy sources supporting the energization of trapped electrons. EHs propagate with velocities from 1000 to 20,000 km/s (a few times larger than the thermal velocity of the coldest background electron population). The parallel scale of observed EHs is from 0.3 to 3 km that i. . .
Date: 12/2016 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023083 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA023083/full
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Authors: Mozer F S, Artemyev A., Agapitov O. V., Mourenas D., and Vasko I.
Title: Near-Relativistic Electron Acceleration by Landau Trapping in Time Domain Structures
Abstract: 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 that the electrostatic fields in TDS may generate the electron seed population for cyclotron resonance interaction with chorus waves to make higher-energy electrons.
Date: 01/2016 Publisher: Geophysical Research Letters DOI: 10.1002/2015GL067316 Available at: http://doi.wiley.com/10.1002/2015GL067316
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Authors: Lejosne ène, and Mozer F S
Title: Typical values of the electric drift E  ×  B / B 2 in the inner radiation belt and slot region as determined from Van Allen Probe measurements
Abstract: The electric drift E × B/B2 plays a fundamental role for the description of plasma flow and particle acceleration. Yet it is not well-known in the inner belt and slot region because of a lack of reliable in situ measurements. In this article, we present an analysis of the electric drifts measured below L ~ 3 by both Van Allen Probes A and B from September 2012 to December 2014. The objective is to determine the typical components of the equatorial electric drift in both radial and azimuthal directions. The dependences of the components on radial distance, magnetic local time, and geographic longitude are examined. The results from Van Allen Probe A agree with Van Allen Probe B. They show, among other things, a typical corotation lag of the order of 5 to 10% below L ~ 2.6, as w. . .
Date: 12/2016 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023613 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA023613/full
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Authors: Lejosne Solène, and Mozer F S
Title: Van Allen Probe measurements of the electric drift E × B/B2 at Arecibo's L = 1.4 field line coordinate
Abstract: We have used electric and magnetic measurements by Van Allen Probe B from 2013 to 2014 to examine the equatorial electric drift E × B/B2 at one field line coordinate set to Arecibo's incoherent scatter radar location (L = 1.43). We report on departures from the traditional picture of corotational motion with the Earth in two ways: (1) the rotational angular speed is found to be 10% smaller than the rotational angular speed of the Earth, in agreement with previous works on plasmaspheric notches, and (2) the equatorial electric drift displays a dependence in magnetic local time, with a pattern consistent with the mapping of the Arecibo ionosphere dynamo electric fields along equipotential magnetic field lines. The electric fields due to the ionosphere dynamo are therefore expected t. . .
Date: 07/2016 Publisher: Geophysical Research Letters Pages: 6768 - 6774 DOI: 10.1002/2016GL069875 Available at: http://doi.wiley.com/10.1002/2016GL069875
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2015
Authors: Artemyev A. V., Agapitov O. V., Mozer F S, and Spence H.
Title: Butterfly pitch-angle distribution of relativistic electrons in the outer radiation belt: Evidence of nonadiabatic scattering
Abstract: 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 distributions over a wide energy range as due to the combined effect of outward radial diffusion and magnetopause shadowing. In this paper we discuss another mechanism that produces butterfly distributions over a limited range of electron energies. We suggest that such distributi. . .
Date: 05/2015 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2014JA020865 Available at: http://doi.wiley.com/10.1002/2014JA020865
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Authors: Drake J. F., Agapitov O. V., and Mozer F S
Title: The development of a bursty precipitation front with intense localized parallel electric fields driven by whistler waves
Abstract: The dynamics and structure of whistler turbulence relevant to electron acceleration in the Earth's outer radiation belt is explored with simulations and comparisons with observations. An initial state with an electron temperature anisotropy in a spatially localized domain drives whistlers which scatter electrons. An outward propagating front of whistlers and hot electrons nonlinearly evolves to form regions of intense parallel electric field with structure similar to observations. The precipitating hot electrons propagate away from the source region in intense bunches rather than as a smooth flux.
Date: 03/2015 Publisher: Geophysical Research Letters DOI: 10.1002/2015GL063528 Available at: http://doi.wiley.com/10.1002/2015GL063528
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Authors: Agapitov O. V., Artemyev A. V., Mourenas D., Mozer F S, and Krasnoselskikh V.
Title: Empirical model of lower band chorus wave distribution in the outer radiation belt
Abstract: 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 (2001–2010) aboard the Cluster spacecraft. We used data from the Spatio-Temporal Analysis of Field Fluctuations-Spectrum Analyzer experiment, which spans a total frequency range from 8 Hz to 4 kHz. The statistical model is presented in the form of an analytical function of latitude and Kp (or Dst) i. . .
Date: 12/2015 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2015JA021829 Available at: http://doi.wiley.com/10.1002/2015JA021829http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2F2015JA021829
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Authors: Agapitov O. V., Krasnoselskikh V., Mozer F S, Artemyev A. V., and Volokitin A. S.
Title: Generation of nonlinear Electric Field Bursts in the outer radiation belt through the parametric decay of whistler waves
Abstract: 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 as analytically, using Van Allen Probes data. The resulting electron acoustic wave is considered to be the source of electron scale TDS. The measured parameters of the three waves (two whistlers and the electron acoustic wave) are in a good agreement with an assumption . . .
Date: 05/2015 Publisher: Geophysical Research Letters DOI: 10.1002/2015GL064145 Available at: http://doi.wiley.com/10.1002/2015GL064145
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Authors: Agapitov O. V., Artemyev A. V., Mourenas D., Mozer F S, and Krasnoselskikh V.
Title: Nonlinear local parallel acceleration of electrons through Landau trapping by oblique whistler mode waves in the outer radiation belt
Abstract: 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 ∼1–10 keV electrons and their acceleration up to 100–300 keV. This kind of process becomes important for oblique whistler mode waves having a significant electric field component along the background magnetic field. In the inhomogeneous geomagnetic field, such resonant interactions then lead to the formation of a plateau in the parallel (with respect to the geomagnetic field) velocity distribution due to trapping of electrons into the wave effective potential. We de. . .
Date: 12/2015 Publisher: Geophysical Research Letters Pages: 10,140 - 10,149 DOI: 10.1002/2015GL066887 Available at: http://doi.wiley.com/10.1002/2015GL066887http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2F2015GL066887
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Authors: Artemyev A. V., Mourenas D., Agapitov O. V., Vainchtein D. L., Mozer F S, et al.
Title: Stability of relativistic electron trapping by strong whistler or electromagnetic ion cyclotron waves
Abstract: In the present paper, we investigate the trapping of relativistic electrons by intense whistler-mode waves or electromagnetic ion cyclotron waves in the Earth's 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 diffusive escape of electrons from the trapped regime of motion and thus can lead to a significant reduction of the efficiency of electron acceleration. We demonstrate that when energetic electrons are trapped by intense parallel or very oblique whistler-mode waves, non-resonant magnetic . . .
Date: 08/2015 Publisher: Physics of Plasmas Pages: 082901 DOI: 10.1063/1.4927774 Available at: http://scitation.aip.org/content/aip/journal/pop/22/8/10.1063/1.4927774
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Authors: Vasko I. Y., Agapitov O. V., Mozer F S, and Artemyev A. V.
Title: Thermal electron acceleration by electric field spikes in the outer radiation belt: Generation of field-aligned pitch angle distributions
Abstract: 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 electrons parallel to the magnetic field via the electrostatic Fermi mechanism, i.e., due to reflections from DL potential humps. The electron energy gain is larger for larger DL scalar potential amplitudes and higher propagation velocities. In addition to the Fermi me. . .
Date: 10/2015 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2015JA021644 Available at: http://doi.wiley.com/10.1002/2015JA021644http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2F2015JA021644
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2014
Authors: Mozer F S, Agapitov O., Krasnoselskikh V., Lejosne S., Reeves G D, et al.
Title: Direct Observation of Radiation-Belt Electron Acceleration from Electron-Volt Energies to Megavolts by Nonlinear Whistlers
Abstract: The mechanisms for accelerating electrons from thermal to relativistic energies in the terrestrial magnetosphere, on the sun, and in many astrophysical environments have never been verified. We present the first direct observation of two processes that, in a chain, cause this acceleration in Earth’s outer radiation belt. The two processes are parallel acceleration from electron-volt to kilovolt energies by parallel electric fields in time-domain structures (TDS), after which the parallel electron velocity becomes sufficiently large for Doppler-shifted upper band whistler frequencies to be in resonance with the electron gyration frequency, even though the electron energies are kilovolts and not hundreds of kilovolts. The electrons are then accelerated by the whistler perpendicular electri. . .
Date: 07/2014 Publisher: Phys. Rev. Lett. Pages: 035001 DOI: 10.1103/PhysRevLett.113.035001 Available at: http://link.aps.org/doi/10.1103/PhysRevLett.113.035001
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2013
Authors: Wygant J R, Bonnell J W, Goetz K, Ergun R E, Mozer F S, et al.
Title: The Electric Field and Waves (EFW) Instruments on the Radiation Belt Storm Probes Mission
Abstract: The Electric Fields and Waves (EFW) Instruments on the two Radiation Belt Storm Probe (RBSP) spacecraft (recently renamed the Van Allen Probes) are designed to measure three dimensional quasi-static and low frequency electric fields and waves associated with the major mechanisms responsible for the acceleration of energetic charged particles in the inner magnetosphere of the Earth. For this measurement, the instrument uses two pairs of spherical double probe sensors at the ends of orthogonal centripetally deployed booms in the spin plane with tip-to-tip separations of 100 meters. The third component of the electric field is measured by two spherical sensors separated by ∼15 m, deployed at the ends of two stacer booms oppositely directed along the spin axis of the spacecraft. The instrume. . .
Date: 11/2013 Publisher: Space Science Reviews DOI: 10.1007/s11214-013-0013-7 Available at: http://link.springer.com/article/10.1007%2Fs11214-013-0013-7
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1979
Authors: Holzworth R H, and Mozer F S
Title: Direct Evaluation of the Radial Diffusion Coefficient near L = 6 Due to Electric Field Fluctuations
Abstract: The radial diffusion coefficient for radiation belt particles near L=6 has been calculated from the measured electric field fluctuations. Simultaneous balloon flights in August 1974 from six auroral zone sites ranging 180° in magnetic longitude produced the electric field data. The large scale slowly varying ionospheric electric fields from these flights have been mapped to the equator during the quiet magnetic conditions of this campaign. These mapped equatorial electric fields were then Fourier transformed in space and time to produce power spectra of the first two terms of the global azimuthal electric field. From these power spectra the radial diffusion coefficient has been calculated.
Date: 06/1979 Publisher: Journal of Geophysical Research Pages: 2559 - 2566 DOI: 10.1029/JA084iA06p02559 Available at: http://onlinelibrary.wiley.com/doi/10.1029/JA084iA06p02559/abstract
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