Biblio

Found 643 results
Filters: Keyword is Van Allen Probes  [Clear All Filters]
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 
O
Authors: Takahashi Kazue, Lysak Robert, Vellante Massimo, Kletzing Craig A., Hartinger Michael D., et al.
Title: Observation and Numerical Simulation of Cavity Mode Oscillations Excited by an Interplanetary Shock
Abstract: Cavity mode oscillations (CMOs) are basic magnetohydrodynamic eigenmodes in the magnetosphere predicted by theory and are expected to occur following the arrival of an interplanetary shock. However, observational studies of shock-induced CMOs have been sparse. We present a case study of a dayside ultra-low-frequency (ULF) wave event that exhibited CMO properties. The event occurred immediately following the arrival of an interplanetary shock at 0829 UT on 15 August 2015. The shock was observed in the solar wind by the Time History of Events and Macroscale Interactions during Substorms-B and -C spacecraft, and magnetospheric ULF waves were observed by multiple spacecraft including the Van Allen Probes-A and -B spacecraft, which were located in the dayside plasmasphere at L∼ 1.4 and L∼ 2. . .
Date: 02/2018 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024639 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA024639/full
More Details
Authors: Aryan Homayon, Sibeck David, Balikhin Michael, Agapitov Oleksiy, and Kletzing Craig
Title: Observation of chorus waves by the Van Allen Probes: Dependence on solar wind parameters and scale size
Abstract: Highly energetic electrons in the Earth's Van Allen radiation belts can cause serious damage to spacecraft electronic systems and affect the atmospheric composition if they precipitate into the upper atmosphere. Whistler mode chorus waves have attracted significant attention in recent decades for their crucial role in the acceleration and loss of energetic electrons that ultimately change the dynamics of the radiation belts. The distribution of these waves in the inner magnetosphere is commonly presented as a function of geomagnetic activity. However, geomagnetic indices are nonspecific parameters that are compiled from imperfectly covered ground based measurements. The present study uses wave data from the two Van Allen Probes to present the distribution of lower band chorus waves not onl. . .
Date: 08/2016 Publisher: Journal of Geophysical Research: Space Physics Pages: 7608 - 7621 DOI: 10.1002/jgra.v121.810.1002/2016JA022775 Available at: http://doi.wiley.com/10.1002/2016JA022775
More Details
Authors: Teng S., Zhao J., Tao X., Wang S., and Reeves G D
Title: Observation of Oblique Lower Band Chorus Generated by Nonlinear Three-Wave Interaction
Abstract: Oblique whistler mode waves have been suggested to play an important role in radiation belt electron dynamics. Recently, Fu et al. [2017] proposed that highly oblique lower band whistler waves could be generated by nonlinear three‐wave resonance. Here we present the first observational evidence of such process, using Van Allen Probes data, where an oblique lower band chorus wave is generated by two quasi‐parallel waves through nonlinear three‐wave interaction. The wave resonance condition is satisfied even in the presence of frequency chirping of one of the pump waves. Different from the simulation results of Fu et al. [2017], simultaneous particle data do not show a plateau in the electron distribution, which could be due to the very weak intensity of the generated waves. These resu. . .
Date: 06/2018 Publisher: Geophysical Research Letters DOI: 10.1029/2018GL078765 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL078765
More Details
Authors: Soto-Chavez A. R., Lanzerotti L J, Manweiler J W, Gerrard A., Cohen R., et al.
Title: Observational evidence of the drift-mirror plasma instability in Earth's inner magnetosphere
Abstract: We report on evidence for the generation of an ultra-low frequency plasma wave by the drift-mirror plasma instability in the dynamic plasma environment of Earth's inner magnetosphere. The plasma measurements are obtained from the Radiation Belt Storm Probes Ion Composition Experiment onboard NASA's Van Allen Probes Satellites. We show that the measured wave-particle interactions are driven by the drift-mirror instability. Theoretical analysis of the data demonstrates that the drift-mirror mode plasma instability condition is well satisfied. We also demonstrate, for the first time, that the measured wave growth rate agrees well with the predicted linear theory growth rate. Hence, the in-situ space plasma observations and theoretical analysis demonstrate that local generation of ultra-low fr. . .
Date: 04/2019 Publisher: Physics of Plasmas Pages: 042110 DOI: 10.1063/1.5083629 Available at: https://doi.org/10.1063/1.5083629
More Details
Authors: Nakamura Satoko, Omura Yoshiharu, Summers Danny, and Kletzing Craig A.
Title: Observational evidence of the nonlinear wave growth theory of plasmaspheric hiss
Abstract: We test the recently developed nonlinear wave growth theory of plasmaspheric hiss against discrete rising tone elements of hiss emissions observed by the Van Allen Probes. From the phase variation of the waveforms processed by bandpass filters, we calculate the instantaneous frequencies and wave amplitudes. We obtain the theoretical relation between the wave amplitude and frequency sweep rates at the observation point by applying the convective growth rates and dispersion factors to the known relation at the equator. By plotting the theoretical relation over scatterplots of the wave amplitudes and the frequency sweep rates for rising tone elements, we find good agreement between the hiss observations and the nonlinear theory. We also find that the duration periods of the hiss elements are . . .
Date: 09/2016 Publisher: Geophysical Research Letters DOI: 10.1002/2016GL070333 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016GL070333/full
More Details
Authors: Ripoll ‐F., Loridan V., Denton M. H., Cunningham G., Reeves G., et al.
Title: Observations and Fokker‐Planck simulations of the L‐shell, energy, and pitch‐angle structure of Earth’s electron radiation belts during quiet times
Abstract: The evolution of the radiation belts in L‐shell (L), energy (E), and equatorial pitch‐angle (α0) is analyzed during the calm 11‐day interval (March 4 –March 15) following the March 1 storm 2013. Magnetic Electron and Ion Spectrometer (MagEIS) observations from Van Allen Probes are interpreted alongside 1D and 3D Fokker‐Planck simulations combined with consistent event‐driven scattering modeling from whistler mode hiss waves. Three (L, E, α0)‐regions persist through 11 days of hiss wave scattering; the pitch‐angle dependent inner belt core (L~<2.2 and E<700 keV), pitch‐angle homogeneous outer belt low‐energy core (L>~5 and E~<100 keV), and a distinct pocket of electrons (L~[4.5, 5.5] and E~[0.7, 2] MeV). The pitch‐angle homogeneous outer belt is explained by the diff. . .
Date: 12/2018 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2018JA026111 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JA026111
More Details
Authors: Breneman A. W., Crew A., Sample J., Klumpar D., Johnson A., et al.
Title: Observations Directly Linking Relativistic Electron Microbursts to Whistler Mode Chorus: Van Allen Probes and FIREBIRD II
Abstract: We present observations that provide the strongest evidence yet that discrete whistler mode chorus packets cause relativistic electron microbursts. On 20 January 2016 near 1944 UT the low Earth orbiting CubeSat Focused Investigations of Relativistic Electron Bursts: Intensity, Range, and Dynamics (FIREBIRD II) observed energetic microbursts (near L = 5.6 and MLT = 10.5) from its lower limit of 220 keV, to 1 MeV. In the outer radiation belt and magnetically conjugate, Van Allen Probe A observed rising‐tone, lower band chorus waves with durations and cadences similar to the microbursts. No other waves were observed. This is the first time that chorus and microbursts have been simultaneously observed with a separation smaller than a chorus packet. A majority of the microbursts do not have t. . .
Date: 11/2017 Publisher: Geophysical Research Letters Pages: 11,265 - 11,272 DOI: 10.1002/2017GL075001 Available at: https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2017GL075001
More Details
Authors: Blum L. W., Halford A., Millan R., Bonnell J. W., Goldstein J, et al.
Title: Observations of coincident EMIC wave activity and duskside energetic electron precipitation on 18-19 January 2013
Abstract: Electromagnetic ion cyclotron (EMIC) waves have been suggested to be a cause of radiation belt electron loss to the atmosphere. Here simultaneous, magnetically conjugate measurements are presented of EMIC wave activity, measured at geosynchronous orbit and on the ground, and energetic electron precipitation, seen by the Balloon Array for Radiation belt Relativistic Electron Losses (BARREL) campaign, on two consecutive days in January 2013. Multiple bursts of precipitation were observed on the duskside of the magnetosphere at the end of 18 January and again late on 19 January, concurrent with particle injections, substorm activity, and enhanced magnetospheric convection. The structure, timing, and spatial extent of the waves are compared to those of the precipitation during both days to det. . .
Date: 07/2015 Publisher: Geophysical Research Letters DOI: 10.1002/2015GL065245 Available at: http://doi.wiley.com/10.1002/2015GL065245
More Details
Authors: Zhang Dianjun, Liu Wenlong, Li Xinlin, Sarris Theodore, Xiao Chao, et al.
Title: Observations of impulsive electric fields induced by Interplanetary Shock
Abstract: We investigate the characteristics of impulsive electric fields in Earth's magnetosphere, as measured by the Van Allen Probes, in association with interplanetary shocks, as measured by ACE and Wind spacecraft in the solar wind from January 2013 to July 2016. It is shown that electric field impulses are mainly induced by global compressions by the shocks, mostly in the azimuthal direction and the amplitudes of the initial electric field impulses are positively correlated with the rate of increase of dynamic pressure across the shock in the dayside. It is also shown that the temporal profile of the impulse is related to the temporal profile of the solar wind dynamic pressure, Pd. It is suggested that during the first period of the impulse the evolution of the electric field is directly contr. . .
Date: 07/2018 Publisher: Geophysical Research Letters DOI: 10.1029/2018GL078809 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL078809
More Details
Authors: Chaston Christopher C., Bonnell J W, Wygant John R., Mozer Forrest, Bale Stuart D., et al.
Title: Observations of kinetic scale field line resonances
Abstract: We identify electromagnetic field variations from the Van Allen Probes which have the properties of Doppler shifted kinetic scale Alfvénic field line resonances. These variations are observed during injections of energetic plasmas into the inner magnetosphere. These waves have scale sizes perpendicular to the magnetic field which are determined to be of the order of an ion gyro-radius (ρi) and less. Cross-spectral analysis of the electric and magnetic fields reveals phase transitions at frequencies correlated with enhancements and depressions in the ratio of the electric and magnetic fields. Modeling shows that these observations are consistent with the excitation of field-line resonances over a broad range of wave numbers perpendicular to the magnetic field (k⊥) extending to k⊥ρi. . .
Date: 01/2014 Publisher: Geophysical Research Letters Pages: 209 - 215 DOI: 10.1002/2013GL058507 Available at: http://doi.wiley.com/10.1002/2013GL058507
More Details
Authors: Foster J. C., Erickson P. J., Baker D N, Jaynes A. N., Mishin E. V., et al.
Title: Observations of the impenetrable barrier, the plasmapause, and the VLF bubble during the 17 March 2015 storm
Abstract: Van Allen Probes observations during the 17 March 2015 major geomagnetic storm strongly suggest that VLF transmitter-induced waves play an important role in sculpting the earthward extent of outer zone MeV electrons. A magnetically confined bubble of very low frequency (VLF) wave emissions of terrestrial, human-produced origin surrounds the Earth. The outer limit of the VLF bubble closely matches the position of an apparent barrier to the inward extent of multi-MeV radiation belt electrons near 2.8 Earth radii. When the VLF transmitter signals extend beyond the eroded plasmapause, electron loss processes set up near the outer extent of the VLF bubble create an earthward limit to the region of local acceleration near L = 2.8 as MeV electrons are scattered into the atmospheric loss cone.
Date: 06/2016 Publisher: Journal of Geophysical Research: Space Physics Pages: 5537 - 5548 DOI: 10.1002/jgra.v121.610.1002/2016JA022509 Available at: http://doi.wiley.com/10.1002/2016JA022509
More Details
Authors: Selesnick R. S., Baker D N, Jaynes A. N., Li X, Kanekal S G, et al.
Title: Observations of the inner radiation belt: CRAND and trapped solar protons
Abstract: Measurements of inner radiation belt protons have been made by the Van Allen Probes Relativistic Electron-Proton Telescopes as a function of kinetic energy (24 to 76 MeV), equatorial pitch angle, and magnetic L shell, during late-2013 and early-2014. A probabilistic data analysis method reduces background from contamination by higher energy protons. Resulting proton intensities are compared to predictions of a theoretical radiation belt model. Then trapped protons originating both from cosmic ray albedo neutron decay (CRAND) and from trapping of solar protons are evident in the measured distributions. An observed double-peaked distribution in L is attributed, based on the model comparison, to a gap in the occurrence of solar proton events during the 2007 to 2011 solar minimum. Equatorial. . .
Date: 08/2014 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2014JA020188 Available at: http://doi.wiley.com/10.1002/2014JA020188
More Details
Authors: Zhang Zhenxia, Chen Lunjin, Li Xinqiao, Xia Zhiyang, Heelis Roderick A., et al.
Title: Observed propagation route of VLF transmitter signals in the magnetosphere
Abstract: Signals of powerful ground transmitters at various places have been detected by satellites in near‐Earth space. The study on propagation mode, ducted or nonducted, has attracted much attentions for several decades. Based on the statistical results from Van Allen Probes (data from Oct. 2012 to Mar. 2017) and DEMETER satellite (from Jan. 2006 to Dec. 2007), we present the ground transmitter signals distributed clearly in ionosphere and magnetosphere. The observed propagation route in the meridian plane in the magnetosphere for each of various transmitters from the combination of DEMETER and Van Allen Probes data in night time is revealed for the first time. We use realistic ray tracing simulation and compare simulation results against Van Allen Probes and DEMETER observation. By comparison. . .
Date: 06/2018 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2018JA025637 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JA025637
More Details
Authors: Saikin A. A., Zhang J.-C., Allen R.C., Smith C W, Kistler L. M., et al.
Title: The occurrence and wave properties of H + -, He + -, and O + -band EMIC waves observed by the Van Allen Probes
Abstract: We perform a statistical study of electromagnetic ion cyclotron (EMIC) waves detected by the Van Allen Probes mission to investigate the spatial distribution of their occurrence, wave power, ellipticity, and normal angle. The Van Allen Probes have been used which allow us to explore the inner magnetosphere (1.1 to 5.8 Re). Magnetic field measurements from the Electric and Magnetic Field Instrument Suite and Integrated Science onboard the Van Allen Probes are used to identify EMIC wave events for the first 22 months of the mission operation (8 September 2012 – 30 June 2014). EMIC waves are examined in H+-, He+-, and O+-bands. Over 700 EMIC wave events have been identified over the three different wave bands (265 H+-band events, 438 He+-band events, and 68 O+-band events). EMIC wave events. . .
Date: 09/2015 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2015JA021358 Available at: http://doi.wiley.com/10.1002/2015JA021358
More Details
Authors: Ni Binbin, Zou Zhengyang, Li Xinlin, Bortnik Jacob, Xie Lun, et al.
Title: Occurrence Characteristics of Outer Zone Relativistic Electron Butterfly Distribution: A Survey of Van Allen Probes REPT Measurements
Abstract: Using Van Allen Probes REPT pitch angle resolved electron flux data from September 2012 to March 2015, we investigate in detail the global occurrence pattern of equatorial (|λ| ≤ 3°) butterfly distribution of outer zone relativistic electrons and its potential correlation with the solar wind dynamic pressure. The statistical results demonstrate that these butterfly distributions occur with the highest occurrence rate ~ 80% at ~ 20 – 04 MLT and L > ~ 5.5 and with the second peak (> ~ 50 %) at ~ 11 – 15 MLT of lower L-shells ~ 4.0. They can also extend to L = 3.5 and to other MLT intervals but with the occurrence rates predominantly < ~25%. It is further shown that outer zone relativistic electron butterfly distributions are likely to peak between . . .
Date: 05/2016 Publisher: Geophysical Research Letters DOI: 10.1002/2016GL069350 Available at: http://doi.wiley.com/10.1002/2016GL069350
More Details
Authors: Liu Xu, Chen Lunjin, Yang Lixia, Xia Zhiyang, and Malaspina David M.
Title: One-Dimensional Full Wave Simulation of Equatorial Magnetosonic Wave Propagation in an Inhomogeneous Magnetosphere
Abstract: The effect of the plasmapause on equatorially radially propagating fast magnetosonic (MS) waves in the Earth's dipole magnetic field is studied by using finite difference time domain method. We run 1-D simulation for three different density profiles: (1) no plasmapause, (2) with a plasmapause, and (3) with a plasmapause accompanied with fine-scale density irregularity. We find that (1) without plasmapause the radially inward propagating MS wave can reach ionosphere and continuously propagate to lower altitude if no damping mechanism is considered. The wave properties follow the cold plasma dispersion relation locally along its trajectory. (2) For simulation with a plasmapause with a scale length of 0.006 RE compared to wavelength, only a small fraction of the MS wave power is reflected by . . .
Date: 01/2018 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024336 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA024336/full
More Details
Authors: Coleman Tim, McCollough James, Young Shawn, and Rigler E. J.
Title: Operational Nowcasting of Electron Flux Levels in the Outer Zone of Earth's Radiation Belt
Abstract: We describe a lightweight, accurate nowcasting model for electron flux levels measured by the Van Allen probes. Largely motivated by Rigler et al. [2004], we turn to a time‐varying linear filter of previous flux levels and Kp. We train and test this model on data gathered from the 2.10 MeV channel of the Relativistic Electron‐Proton Telescope (REPT) sensor onboard the Van Allen probes. Dynamic linear models are a specific case of state space models, and can be made flexible enough to emulate the nonlinear behavior of particle fluxes within the radiation belts. Real‐time estimation of the parameters of the model is done using a Kalman Filter, where the state of the model is exactly the parameters. Nowcast performance is assessed against several baseline interpolation schemes. Our mode. . .
Date: 04/2018 Publisher: Space Weather DOI: 10.1029/2017SW001788 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2017SW001788
More Details
Authors: Denton M. H., Reeves G D, Larsen B A, Friedel R. F. W., Thomsen M F, et al.
Title: On the origin of low-energy electrons in the inner magnetosphere: Fluxes and pitch-angle distributions
Abstract: Accurate knowledge of the plasma fluxes in the inner magnetosphere is essential for both scientific and programmatic applications. Knowledge of the low-energy electrons (approximately tens to hundreds of eV) in the inner magnetosphere is particularly important since these electrons are acted upon by various physical processes, accelerating the electrons to higher energies, and also causing their loss. However, measurements of low-energy electrons are challenging, and as a result, this population has been somewhat neglected previously. This study concerns observations of low-energy electrons made by the Helium Oxygen Proton Electron instrument on board the Van Allen Probes satellites and also observations from geosynchronous orbit made by the Magnetospheric Plasma Analyzer on board Los Alam. . .
Date: 02/2017 Publisher: Journal of Geophysical Research: Space Physics Pages: 1789–1802 DOI: 10.1002/2016JA023648 Available at: onlinelibrary.wiley.com/doi/10.1002/2016JA023648/full
More Details
Authors: Denton M. H., Reeves G. D., Larsen B. A., Friedel R. F. W., Thomsen M. F., et al.
Title: On the origin of low-energy electrons in the inner magnetosphere: Fluxes and pitch-angle distributions
Abstract: Accurate knowledge of the plasma fluxes in the inner magnetosphere is essential for both scientific and programmatic applications. Knowledge of the low-energy electrons (approximately tens to hundreds of eV) in the inner magnetosphere is particularly important since these electrons are acted upon by various physical processes, accelerating the electrons to higher energies, and also causing their loss. However, measurements of low-energy electrons are challenging, and as a result, this population has been somewhat neglected previously. This study concerns observations of low-energy electrons made by the Helium Oxygen Proton Electron instrument on board the Van Allen Probes satellites and also observations from geosynchronous orbit made by the Magnetospheric Plasma Analyzer on board Los Alam. . .
Date: 01/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023648 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA023648
More Details
Authors: Bingham S. T., Mouikis C. G., Kistler L. M., Boyd A. J., Paulson K., et al.
Title: The outer radiation belt response to the storm time development of seed electrons and chorus wave activity during CME and CIR storms
Abstract: Gyroresonant wave‐particle interactions with very low frequency whistler mode chorus waves can accelerate subrelativistic seed electrons (hundreds of keV) to relativistic energies in the outer radiation belt during geomagnetic storms. In this study, we conduct a superposed epoch analysis of the chorus wave activity, the seed electron development, and the outer radiation belt electron response between L* = 2.5 and 5.5, for 25 coronal mass ejection and 35 corotating interaction region storms using Van Allen Probes observations. Electron data from the Magnetic Electron Ion Spectrometer and Relativistic Electron Proton Telescope instruments are used to monitor the storm‐phase development of the seed and relativistic electrons, and magnetic field measurements from the Electric and Magnetic . . .
Date: 12/2018 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2018JA025963 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JA025963
More Details
Authors: Kilpua E. K. J., Turner D. L., Jaynes A. N., Hietala H., Koskinen H. E. J., et al.
Title: Outer Van Allen Radiation Belt Response to Interacting Interplanetary Coronal Mass Ejections
Abstract: We study the response of the outer Van Allen radiation belt during an intense magnetic storm on 15–22 February 2014. Four interplanetary coronal mass ejections (ICMEs) arrived at Earth, of which the three last ones were interacting. Using data from the Van Allen Probes, we report the first detailed investigation of electron fluxes from source (tens of kiloelectron volts) to core (megaelectron volts) energies and possible loss and acceleration mechanisms as a response to substructures (shock, sheath and ejecta, and regions of shock‐compressed ejecta) in multiple interacting ICMEs. After an initial enhancement induced by a shock compression of the magnetosphere, core fluxes strongly depleted and stayed low for 4 days. This sustained depletion can be related to a sequence of ICME substruc. . .
Date: 03/2019 Publisher: Journal of Geophysical Research: Space Physics Pages: 1927 - 1947 DOI: 10.1029/2018JA026238 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JA026238
More Details
Authors: Spence H. E., Reeves G. D., and Kessel R. L.
Title: An Overview of Early Results from the Radiation Belt Storm Probes Energetic Particle, Composition, and Thermal Plasma Suite on NASA's Van Allen Probes Mission
Abstract: N/A
Date: Publisher: Oxford University Press DOI: N/A
More Details
Authors: Xiongdong Yu, Zhigang Yuan, Dedong Wang, Shiyong Huang, Haimeng Li, et al.
Title: Oxygen cyclotron harmonic waves observed by the Van Allen Probes
Abstract: Fine structured multiple-harmonic electromagnetic emissions at frequencies around the equatorial oxygen cyclotron harmonics are observed by Van Allen Probe A outside the core plasmasphere (L~5) off the magnetic equator (MLAT~-7.5°) during a magnetic storm. We find that the multiple-harmonic emissions have their PSD peaks at 2~8 equatorial oxygen gyro-harmonics (f~nfO+, n=2~8) while the fundamental mode (n=1) is absent, implying that the harmonic waves are generated near the equator and propagate into the observation region. Additionally these electromagnetic emissions are linear polarized. Different from the equatorial noise emission propagating very obliquely, these emissions have moderate wave normal angles (about 40°~60°) which predominately become larger as the harmonic number incre. . .
Date: 03/2017 Publisher: Science China: Earth Sciences DOI: 10.1007/s11430-016-9024-3 Available at: http://engine.scichina.com/publisher/scp/journal/SCES/doi/10.1007/s11430-016-9024-3
More Details
P
Authors: Zimbardo Gaetano
Title: A Particle Accelerator in the Radiation Belts
Abstract: Satellites in the radiation belts reveal plasma structures that can jumpstart the acceleration of electrons to very high energies.
Date: 11/2013 Publisher: Physics DOI: 10.1103/Physics.6.131 Available at: http://dx.doi.org/10.1103/Physics.6.131
More Details
Authors: Zhao H., Li X, Blake J B, Fennell J. F., Claudepierre S G, et al.
Title: Peculiar pitch angle distribution of relativistic electrons in the inner radiation belt and slot region
Abstract: The relativistic electrons in the inner radiation belt have received little attention in the past due to sparse measurements and unforgiving contamination from the inner belt protons. The high-quality measurements of the Magnetic Electron Ion Spectrometer instrument onboard Van Allen Probes provide a great opportunity to investigate the dynamics of relativistic electrons in the low L region. In this letter, we report the newly unveiled pitch angle distribution (PAD) of the energetic electrons with minima at 90° near the magnetic equator in the inner belt and slot region. Such a PAD is persistently present throughout the inner belt and appears in the slot region during storms. One hypothesis for 90° minimum PADs is that off 90° electrons are preferentially heated by chorus waves just out. . .
Date: 04/2014 Publisher: Geophysical Research Letters Pages: 2250 - 2257 DOI: 10.1002/2014GL059725 Available at: http://doi.wiley.com/10.1002/2014GL059725
More Details
Authors: Xiao Fuliang, Zhou Qinghua, He Yihua, Yang Chang, Liu Si, et al.
Title: Penetration of magnetosonic waves into the plasmasphere observed by the Van Allen Probes
Abstract: During the small storm on 14–15 April 2014, Van Allen Probe A measured a continuously distinct proton ring distribution and enhanced magnetosonic (MS) waves along its orbit outside the plasmapause. Inside the plasmasphere, strong MS waves were still present but the distinct proton ring distribution was falling steeply with distance. We adopt a sum of subtracted bi-Maxwellian components to model the observed proton ring distribution and simulate the wave trajectory and growth. MS waves at first propagate toward lower L shells outside the plasmasphere, with rapidly increasing path gains related to the continuous proton ring distribution. The waves then gradually cross the plasmapause into the deep plasmasphere, with almost unchanged path gains due to the falling proton ring distribution an. . .
Date: 09/2015 Publisher: Geophysical Research Letters DOI: 10.1002/2015GL065745 Available at: http://onlinelibrary.wiley.com/wol1/doi/10.1002/2015GL065745/full
More Details
Authors: Westlake J. H., Cohen I. J., Mauk B H, Anderson B J, Mitchell D G, et al.
Title: The permeability of the magnetopause to a multispecies substorm injection of energetic particles
Abstract: Leakage of ions from the magnetosphere into the magnetosheath remains an important topic in understanding the plasma physics of Earth's magnetopause and the interaction of the solar wind with the magnetosphere. Here using sophisticated instrumentation from two spacecraft (Radiation Belt Storm Probes Ion Composition Experiment on the Van Allen Probes and Energetic Ion Spectrometer on the Magnetospheric Multiscale) spaced uniquely near and outside the dayside magnetopause, we are able to determine the escape mechanisms for large gyroradii oxygen ions and much smaller gyroradii hydrogen and helium ions. The oxygen ions are entrained on the magnetosphere boundary, while the hydrogen and helium ions appear to escape along reconnected field lines. These results have important implications for no. . .
Date: 09/2016 Publisher: Geophysical Research Letters DOI: 10.1002/2016GL070189 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016GL070189/full
More Details
Authors: Morley S. K., Henderson M G, Reeves G D, Friedel R H W, and Baker D N
Title: Phase Space Density matching of relativistic electrons using the Van Allen Probes: REPT results
Abstract: 1] Phase Space Density (PSD) matching can be used to identify the presence of nonadiabatic processes, evaluate accuracy of magnetic field models, or to cross-calibrate instruments. Calculating PSD in adiabatic invariant coordinates requires a global specification of the magnetic field. For a well specified global magnetic field, nonadiabatic processes or inadequate cross calibration will give a poor PSD match. We have calculated PSD(μ, K) for both Van Allen Probes using a range of models and compare these PSDs at conjunctions in L* (for given μ, K). We quantitatively assess the relative goodness of each model for radiation belt applications. We also quantify the uncertainty in the model magnetic field magnitude and the related uncertainties in PSD, which has applications for modeling and. . .
Date: 09/2013 Publisher: Geophysical Research Letters Pages: 4798–4802 DOI: 10.1002/grl.50909 Available at: http://doi.wiley.com/10.1002/grl.50909
More Details
Authors: Zhang X.-J., Li W, Thorne R M, Angelopoulos V, Ma Q, et al.
Title: Physical mechanism causing rapid changes in ultrarelativistic electron pitch angle distributions right after a shock arrival: Evaluation of an electron dropout event
Abstract: Three mechanisms have been proposed to explain relativistic electron flux depletions (dropouts) in the Earth's outer radiation belt during storm times: adiabatic expansion of electron drift shells due to a decrease in magnetic field strength, magnetopause shadowing and subsequent outward radial diffusion, and precipitation into the atmosphere (driven by EMIC wave scattering). Which mechanism predominates in causing electron dropouts commonly observed in the outer radiation belt is still debatable. In the present study, we evaluate the physical mechanism that may be primarily responsible for causing the sudden change in relativistic electron pitch angle distributions during a dropout event observed by Van Allen Probes during the main phase of the 27 February 2014 storm. During this event, t. . .
Date: 09/2016 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA022517 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA022517/abstract
More Details
Authors: Chaston C. C., Bonnell J. W., Halford A J, Reeves G D, Baker D N, et al.
Title: Pitch Angle Scattering and Loss of Radiation Belt Electrons in Broadband Electromagnetic Waves
Abstract: A magnetic conjunction between Van Allen Probes spacecraft and the Balloon Array for Radiation‐belt Relativistic Electron Losses (BARREL) reveals the simultaneous occurrence of broadband Alfvénic fluctuations and multi‐timescale modulation of enhanced atmospheric X‐ray bremsstrahlung emission. The properties of the Alfvénic fluctuations are used to build a model for pitch angle scattering in the outer radiation belt on electron gyro‐radii scale field structures. It is shown that this scattering may lead to the transport of electrons into the loss cone over an energy range from hundreds of keV to multi‐MeV on diffusive timescales on the order of hours. This process may account for modulation of atmospheric X‐ray fluxes observed from balloons and constitute a significant loss p. . .
Date: 09/2018 Publisher: Geophysical Research Letters DOI: 10.1029/2018GL079527 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL079527
More Details
Authors: Eshetu W. W., Lyon J G, Hudson M K, and Wiltberger M. J.
Title: Pitch Angle Scattering of Energetic Electrons by BBFs
Abstract: Field line curvature scattering by the magnetic field structure associated with bursty bulk flows (BBFs) has been studied, using simulated output fields from the Lyon‐Fedder‐Mobarry global magnetohydrodynamic code for specified solar wind input. There are weak magnetic field strength (B) regions adjacent to BBFs observed in the simulations. We show that these regions can cause strong scattering where the first adiabatic invariant changes by several factors within one equatorial crossing of energetic electrons of a few kiloelectron volts when the BBFs are beyond 10RE geocentric in the tail. Scattering by BBFs decreases as they move toward the Earth or when the electron energy decreases. For radiation belt electrons near or inside geosynchronous orbit we demonstrate that the fields assoc. . .
Date: 10/2018 Publisher: Journal of Geophysical Research: Space Physics Pages: 9265 - 9274 DOI: 10.1029/2018JA025788 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JA025788
More Details
Authors: Artemyev A. V., Zhang X.-J., Angelopoulos V, Runov A., Spence H E, et al.
Title: Plasma anisotropies and currents in the near-Earth plasma sheet and inner magnetosphere
Abstract: 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 and Van Allen Probes in this transition region we obtain radial profiles of ion and electron temperatures and anisotropies for various geomagnetic activity levels. Ion and electron anisotropies vary with the geomagnetic activity in opposite directions. Paralle. . .
Date: 06/2018 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2018JA025232 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JA025232
More Details
Authors: Fernandes Philip A., Larsen Brian A., Thomsen Michelle F., Skoug Ruth M., Reeves Geoffrey D, et al.
Title: The plasma environment inside geostationary orbit: A Van Allen Probes HOPE survey
Abstract: The two full precessions in local time completed by the Van Allen Probes enable global specification of the near-equatorial inner magnetosphere plasma environment. Observations by the Helium-Oxygen-Proton-Electron (HOPE) mass spectrometers provide detailed insight into the global spatial distribution of electrons, H+, He+, and O+. Near-equatorial omnidirectional fluxes and abundance ratios at energies 0.1–30 keV are presented for 2 ≤ L ≤ 6 as a function of L shell, magnetic local time (MLT), and geomagnetic activity. We present a new tool built on the UBK modeling technique for classifying plasma sheet particle access to the inner magnetosphere. This new tool generates access maps for particles of constant energy for more direct comparison with in situ measurements, rather than the t. . .
Date: 08/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024160 Available at: onlinelibrary.wiley.com/doi/10.1002/2017JA024160/full
More Details
Authors: Zhu Hui, Su Zhenpeng, Xiao Fuliang, Zheng Huinan, Wang Yuming, et al.
Title: Plasmatrough exohiss waves observed by Van Allen Probes: Evidence for leakage from plasmasphere and resonant scattering of radiation belt electrons
Abstract: Exohiss waves are whistler mode hiss observed in the plasmatrough region. We present a case study of exohiss waves and the corresponding background plasma distributions observed by the Van Allen Probes in the dayside low-latitude region. The analysis of wave Poynting fluxes, suprathermal electron fluxes and cold electron densities supports the scenario that exohiss leaks from the plasmasphere into the plasmatrough. Quasilinear calculations further reveal that exohiss can potentially cause the resonant scattering loss of radiation belt electrons ~Date: 02/2015 Publisher: Geophysical Research Letters DOI: 10.1002/2014GL062964 Available at: http://doi.wiley.com/10.1002/2014GL062964
More Details
Authors: Wang C., Rankin R, Wang Y., Zong Q.-G., Zhou X., et al.
Title: Poloidal mode wave-particle interactions inferred from Van Allen Probes and CARISMA ground-based observations
Abstract: Ultra‐low‐frequency (ULF) wave and test particle models are used to investigate the pitch angle and energy dependence of ion differential fluxes measured by the Van Allen Probes spacecraft on October 6th, 2012. Analysis of the satellite data reveals modulations in differential flux resulting from drift resonance between H+ ions and fundamental mode poloidal Alfvén waves detected near the magnetic equator at L∼5.7. Results obtained from simulations reproduce important features of the observations, including a substantial enhancement of the differential flux between ∼20° − 40° pitch angle for ion energies between ∼90 − 220keV, and an absence of flux modulations at 90°. The numerical results confirm predictions of drift‐bounce resonance theory and show good quantit. . .
Date: 05/2018 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2017JA025123 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2017JA025123
More Details
Authors: Yang Chang, Su Zhenpeng, Xiao Fuliang, Zheng Huinan, Wang Yuming, et al.
Title: A positive correlation between energetic electron butterfly distributions and magnetosonic waves in the radiation belt slot region
Abstract: Energetic (hundreds of keV) electrons in the radiation belt slot region have been found to exhibit the butterfly pitch angle distributions. Resonant interactions with magnetosonic and whistler-mode waves are two potential mechanisms for the formation of these peculiar distributions. Here we perform a statistical study of energetic electron pitch angle distribution characteristics measured by Van Allen Probes in the slot region during a three-year period from May 2013 to May 2016. Our results show that electron butterfly distributions are closely related to magnetosonic waves rather than to whistler-mode waves. Both electron butterfly distributions and magnetosonic waves occur more frequently at the geomagnetically active times than at the quiet times. In a statistical sense, more distinct . . .
Date: 03/2017 Publisher: Geophysical Research Letters DOI: 10.1002/2017GL073116 Available at: http://doi.wiley.com/10.1002/2017GL073116
More Details
Authors: Sarno-Smith Lois K., Liemohn Michael W., Katus Roxanne M., Skoug Ruth M., Larsen Brian A., et al.
Title: Postmidnight depletion of the high-energy tail of the quiet plasmasphere
Abstract: The Van Allen Probes Helium Oxygen Proton Electron (HOPE) instrument measures the high-energy tail of the thermal plasmasphere allowing study of topside ionosphere and inner magnetosphere coupling. We statistically analyze a 22 month period of HOPE data, looking at quiet times with a Kp index of less than 3. We investigate the high-energy range of the plasmasphere, which consists of ions at energies between 1 and 10 eV and contains approximately 5% of total plasmaspheric density. Both the fluxes and partial plasma densities over this energy range show H+ is depleted the most in the postmidnight sector (1–4 magnetic local time), followed by O+ and then He+. The relative depletion of each species across the postmidnight sector is not ordered by mass, which reveals ionospheric influence. We. . .
Date: 03/2015 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2014JA020682 Available at: http://doi.wiley.com/10.1002/2014JA020682
More Details
Authors: Yuan Zhigang, Liu Kun, Yu Xiongdong, Yao Fei, Huang Shiyong, et al.
Title: Precipitation of radiation belt electrons by EMIC waves with conjugated observations of NOAA and Van Allen satellites
Abstract: In this letter, we present unique conjugated satellite observations of MeV relativistic electron precipitation caused by electromagnetic ion cyclotron (EMIC) waves. On the outer boundary of the plasmasphere, the Van Allen probe observed EMIC waves. At ionospheric altitudes, the NOAA 16 satellite at the footprint of Van Allen probe simultaneously detected obvious flux enhancements for precipitating >MeV radiation belt electrons, but not for precipitating MeV radiation belt electrons. Our result provides a direct magnetic conjugated observational link between in‐situ inner magnetospheric EMIC wav. . .
Date: 11/2018 Publisher: Geophysical Research Letters DOI: 10.1029/2018GL080481 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL080481
More Details
Authors: Sakaguchi Kaori, Nagatsuma Tsutomu, Reeves Geoffrey, and Spence Harlan E.
Title: Prediction of MeV electron fluxes throughout the outer radiation belt using multivariate autoregressive models
Abstract: The Van Allen radiation belts surrounding the Earth are filled with MeV-energy electrons. This region poses ionizing radiation risks for spacecraft that operate within it, including those in geostationary (GEO) and medium Earth orbit (MEO). To provide alerts of electron flux enhancements, sixteen prediction models of the electron log-flux variation throughout the equatorial outer radiation belt as a function of the McIlwain L parameter were developed using the multivariate autoregressive model and Kalman filter. Measurements of omni-directional 2.3 MeV electron flux from the Van Allen Probes mission as well as >2 MeV electrons from the GOES-15 spacecraft were used as the predictors. Model explanatory parameters were selected from solar wind parameters, the electron log-flux at GEO, and geo. . .
Date: 11/2015 Publisher: Space Weather Pages: n/a - n/a DOI: 10.1002/2015SW001254 Available at: http://doi.wiley.com/10.1002/2015SW001254http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2F2015SW001254
More Details
Authors: Fox N J, and Burch J L
Title: Preface
Abstract: The discovery of the Van Allen radiation belts in 1958, starting with data from the United States’ first two successful orbiting spacecraft, Explorer’s I and III, was an astounding surprise and represented the founding of what we now call magnetospheric physics. Since that time many spacecraft have traversed the radiation belts en route to other more distant parts of Earth’s magnetosphere and other worlds beyond Earth’s orbit. After initial climatological models of the radiation belts were obtained in the 1960’s and early 1970’s, the main concern about them was the ability of spacecraft and astronauts to survive their intense radiation. And yet there were true scientific mysteries to be solved, glimpses of which came in the 1990’s from spacecraft like CRRES and SAMPEX. CRRES . . .
Date: 11/2013 Publisher: Space Science Reviews Pages: 1-2 DOI: 10.1007/s11214-013-9997-2 Available at: http://link.springer.com/article/10.1007%2Fs11214-013-9997-2
More Details
Authors: Chen Yue, Reeves Geoffrey D, Fu Xiangrong, and Henderson Michael
Title: PreMevE: New Predictive Model for Megaelectron-volt Electrons inside Earth's Outer Radiation Belt
Abstract: This work designs a new model called PreMevE to predict storm‐time distributions of relativistic electrons within Earth's outer radiation belt. This model takes advantage of the cross‐energy, ‐L‐shell, and –pitch‐angle coherence associated with wave‐electron resonant interactions, ingests observations from belt boundaries—mainly by NOAA POES in low‐Earth‐orbits (LEOs), and provides high‐fidelity nowcast (multiple‐hour prediction) and forecast (> ~1 day) of MeV electron fluxes over L‐shells between 2.8‐7 through linear prediction filters. PreMevE can not only reliably anticipate incoming enhancements of MeV electrons during storms with at least 1‐day forewarning time, but also accurately specify the evolving event‐specific electron spatial distributions after. . .
Date: 02/2019 Publisher: Space Weather DOI: 10.1029/2018SW002095 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018SW002095
More Details
Authors: Kletzing Craig A.
Title: Progress on understanding chorus emissions from data of the electric and magnetic field instrument suite and integrated science (EMFISIS) on the Van Allen Probes
Abstract: The physics of the creation, loss, and transport of radiation belt particles is intimately connected to the electric and magnetic fields which mediate these processes. A key wave-particle interaction important to both acceleration and loss in the radiation belts is the of whistler-mode chorus interacting with energetic electrons. To measure this important radiation belt interaction, the two-satellite Van Allen Probes mission utilizes one of the most complete sets of measurements ever made in the inner magnetosphere. As part of the mission, the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) investigation is an integrated set of instruments consisting of a tri-axial fluxgate magnetometer (MAG) and a Waves instrument which includes a tri-axial search coil magnet. . .
Date: 08/2014 Publisher: IEEE DOI: 10.1109/URSIGASS.2014.6929872 Available at: http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6929872
More Details
Authors: Kanekal S G, Baker D N, Fennell J. F., Jones A., Schiller Q., et al.
Title: Prompt acceleration of magnetospheric electrons to ultrarelativistic energies by the 17 March 2015 interplanetary shock
Abstract: Trapped electrons in Earth's outer Van Allen radiation belt are influenced profoundly by solar phenomena such as high-speed solar wind streams, coronal mass ejections (CME), and interplanetary (IP) shocks. In particular, strong IP shocks compress the magnetosphere suddenly and result in rapid energization of electrons within minutes. It is believed that the electric fields induced by the rapid change in the geomagnetic field are responsible for the energization. During the latter part of March 2015, a CME impact led to the most powerful geomagnetic storm (minimum Dst = −223 nT at 17 March, 23 UT) observed not only during the Van Allen Probe era but also the entire preceding decade. Magnetospheric response in the outer radiation belt eventually resulted in elevated levels of energized ele. . .
Date: 08/2016 Publisher: Journal of Geophysical Research: Space Physics Pages: 7622 - 7635 DOI: 10.1002/2016JA022596 Available at: http://doi.wiley.com/10.1002/2016JA022596
More Details
Authors: Liu Nigang, Su Zhenpeng, Zheng Huinan, Wang Yuming, and Wang Shui
Title: Prompt Disappearance and Emergence of Radiation Belt Magnetosonic Waves Induced by Solar Wind Dynamic Pressure Variations
Abstract: Magnetosonic waves are highly oblique whistler mode emissions transferring energy from the ring current protons to the radiation belt electrons in the inner magnetosphere. Here we present the first report of prompt disappearance and emergence of magnetosonic waves induced by the solar wind dynamic pressure variations. The solar wind dynamic pressure reduction caused the magnetosphere expansion, adiabatically decelerated the ring current protons for the Bernstein mode instability, and produced the prompt disappearance of magnetosonic waves. On the contrary, because of the adiabatic acceleration of the ring current protons by the solar wind dynamic pressure enhancement, magnetosonic waves emerged suddenly. In the absence of impulsive injections of hot protons, magnetosonic waves were observa. . .
Date: 01/2018 Publisher: Geophysical Research Letters DOI: 10.1002/2017GL076382 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017GL076382/full
More Details
Authors: Foster John C, and Erickson Philip J.
Title: Prompt energization of relativistic and highly relativistic electrons during a substorm interval
Abstract: On 17 March 2013, a large magnetic storm significantly depleted the multi-MeV radiation belt. We present multi-instrument observations from the Van Allen Probes spacecraft Radiation Belt Storm Probe A and Radiation Belt Storm Probe B at ∼6 Re in the midnight sector magnetosphere and from ground-based ionospheric sensors during a substorm dipolarization followed by rapid reenergization of multi-MeV electrons [1]. A 50% increase in magnetic field magnitude occurred simultaneously with dramatic increases in 100 keV electron fluxes and a 100 times increase in VLF wave intensity. Chorus is excited following the injection of low-energy (1–30 keV) plasma sheet electrons into the inner magnetosphere [2]. During the 17 March substorm injection, cold plasma that had circulated into the nightside. . .
Date: 08/2014 Publisher: IEEE DOI: 10.1109/URSIGASS.2014.6929876 Available at: http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6929876
More Details
Authors: Foster J. C., Erickson P. J., Baker D N, Claudepierre S G, Kletzing C A, et al.
Title: Prompt energization of relativistic and highly relativistic electrons during a substorm interval: Van Allen Probes observations
Abstract: On 17 March 2013, a large magnetic storm significantly depleted the multi-MeV radiation belt. We present multi-instrument observations from the Van Allen Probes spacecraft Radiation Belt Storm Probe A and Radiation Belt Storm Probe B at ~6 Re in the midnight sector magnetosphere and from ground-based ionospheric sensors during a substorm dipolarization followed by rapid reenergization of multi-MeV electrons. A 50% increase in magnetic field magnitude occurred simultaneously with dramatic increases in 100 keV electron fluxes and a 100 times increase in VLF wave intensity. The 100 keV electrons and intense VLF waves provide a seed population and energy source for subsequent radiation belt enhancements. Highly relativistic (>2 MeV) electron fluxes increased immediately at L* ~ 4.5. . .
Date: 01/2014 Publisher: Geophysical Research Letters Pages: 20 - 25 DOI: 10.1002/2013GL058438 Available at: http://doi.wiley.com/10.1002/2013GL058438
More Details
Authors: Schiller Q., Kanekal S G, Jian L. K., Li X, Jones A., et al.
Title: Prompt injections of highly relativistic electrons induced by interplanetary shocks: A statistical study of Van Allen Probes observations
Abstract: We conduct a statistical study on the sudden response of outer radiation belt electrons due to interplanetary (IP) shocks during the Van Allen Probes era, i.e., 2012 to 2015. Data from the Relativistic Electron-Proton Telescope instrument on board Van Allen Probes are used to investigate the highly relativistic electron response (E > 1.8 MeV) within the first few minutes after shock impact. We investigate the relationship of IP shock parameters, such as Mach number, with the highly relativistic electron response, including spectral properties and radial location of the shock-induced injection. We find that the driving solar wind structure of the shock does not affect occurrence for enhancement events, 25% of IP shocks are associated with prompt energization, and 14% are associated wi. . .
Date: 12/2016 Publisher: Geophysical Research Letters DOI: 10.1002/2016GL071628 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016GL071628/full
More Details
Authors: Yu J., Li L. Y., Cao J. B., Chen L, Wang J., et al.
Title: Propagation characteristics of plasmaspheric hiss: Van Allen Probe observations and global empirical models
Abstract: Based on the Van Allen Probe A observations from 1 October 2012 to 31 December 2014, we develop two empirical models to respectively describe the hiss wave normal angle (WNA) and amplitude variations in the Earth's plasmasphere for different substorm activities. The long-term observations indicate that the plasmaspheric hiss amplitudes on the dayside increase when substorm activity is enhanced (AE index increases), and the dayside hiss amplitudes are greater than the nightside. However, the propagation angles (WNAs) of hiss waves in most regions do not depend strongly on substorm activity, except for the intense substorm-induced increase in WNAs in the nightside low L-region. The propagation angles of plasmaspheric hiss increase with increasing magnetic latitude or decreasing radial distan. . .
Date: 04/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023372 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA023372/full
More Details
Authors: Takahashi Kazue, Hartinger Michael D., Malaspina David M., Smith Charles W., Koga Kiyokazu, et al.
Title: Propagation of ULF waves from the upstream region to the midnight sector of the inner magnetosphere
Abstract: Ultralow frequency (ULF) waves generated in the ion foreshock are a well-known source of Pc3-Pc4 waves (7–100 mHz) observed in the dayside magnetosphere. We use data acquired on 10 April 2013 by multiple spacecraft to demonstrate that ULF waves of upstream origin can propagate to the midnight sector of the inner magnetosphere. At 1130–1730 UT on the selected day, the two Van Allen Probes spacecraft and the geostationary ETS-VIII satellite detected compressional 20 to 40 mHz magnetic field oscillations between L ∼ 4 and L ∼ 7 in the midnight sector, along with other spacecraft located closer to noon. Upstream origin of the oscillations is concluded from the wave frequency that matches a theoretical model, globally coherent amplitude modulation, and duskward propagation that is consi. . .
Date: 08/2016 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA022958 Available at: http://doi.wiley.com/10.1002/2016JA022958
More Details
Authors: Zhang X.-J., Thorne R., Artemyev A., Mourenas D., Angelopoulos V, et al.
Title: Properties of intense field-aligned lower-band chorus waves: Implications for nonlinear wave-particle interactions
Abstract: 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 describe individual short‐term events, are not directly applicable for a statistical evaluation of nonlinear effects and the long‐term dynamics of the outer radiation belt, because they lack information on the properties of intense (nonlinearly resonating with e. . .
Date: 06/2018 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2018JA025390 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JA025390
More Details

Pages