Bibliography





Van Allen Probes Bibliography is from August 2012 through September 2021

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Found 37 entries in the Bibliography.


Showing entries from 1 through 37


2021

The effect of non-storm time substorms on the ring current dynamics

Abstract During geomagnetically active times such as geomagnetic storms, large amounts of energy can be released into the Earth’s magnetosphere and change the ring current intensity. Previous studies showed that significant enhancement of the ring current was related to geomagnetic storms, while few studies have examined substorm effects on ring current dynamics. In this study, we examine the ring current variation during non-storm time (SYM-H > −50 nT) substorms, especially during super-substorms ( AE > 1000 nT). We per ...

Jang, Eunjin; Yue, Chao; Zong, Qiugang; Fu, Suiyan; Fu, HaoBo;

Published by: Earth and Planetary Physics      Published on: 06/2021

YEAR: 2021     DOI: https://doi.org/10.26464/epp2021032

super-substorms; ring current; ion fluxes; Van Allen Probes

The Characteristics of Three-belt Structure of Sub-MeV Electrons in the Radiation Belts

Abstract After the launch of Van Allen Probes, the three-belt structures of ultra-relativistic electrons are discovered. In this study, we investigate the three-belt structures of sub-MeV electrons, which may form under different mechanism compared with those of ultra-relativistic electrons and are worth in-depth analysis. Based on the differential flux data from MagEIS onboard RBSP-B satellite, we find 54 events, in which two comparable peaks of sub-MeV electron fluxes and a slot appear where there should be the outer radia ...

Li, Yu-Xuan; Yue, Chao; Hao, Yi-Xin; Zong, Qiu-Gang; Zhou, Xu-Zhi; Fu, Sui-Yan; Chen, Xing-Ran; Zhao, Xing-Xin;

Published by: Journal of Geophysical Research: Space Physics      Published on: 06/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021JA029385

Van Allen Probes

The Link between Wedge-like and Nose-like Ion Spectral Structures in the Inner Magnetosphere

AbstractThe wedge-like and nose-like ion spectral structures, named after their characteristic shapes in the energy-time spectrograms, appear to be distinctively different structures in the Earth s inner magnetosphere. Here we present a case study with conjugate observations from the Arase spacecraft and the twin Van Allen Probes on July 1 and 2, 2017, which displayed the characteristic signatures of the wedge-like and nose-like ion structures, respectively. When the spacecraft nearly intersected at L =2.8, the two structure ...

Ren, Jie; Zhou, Xu-Zhi; Zong, Qiu-Gang; Yue, Chao; Fu, Sui-Yan; Miyoshi, Y.; Zhang, Xiao-Xin; Asamura, K.; Shinohara, I.;

Published by: Geophysical Research Letters      Published on: 06/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021GL093930

Van Allen Probes

Origin of Electron Boomerang Stripes: Statistical Study

Abstract In the outer radiation belt, localized ULF waves can interact with energetic electrons by drift resonance, leading to quasiperiodic oscillations. The oscillations in the pitch angle spectrum can be characterized by either boomerang-shaped or straight stripes. Previous studies have shown that boomerang-shaped stripes evolve from straight ones when electrons drift away from the localized wave interaction region. Based on the time-of-flight technique on the pitch angle-dependent drift velocity, the origin can be remote ...

Zhao, X.; Hao, Y.; Zong, Q.; Zhou, X.; Yue, Chao; Chen, X.; Liu, Y.; Liu, Z.-Y.; Blake, J.; Claudepierre, S.; Reeves, G.;

Published by: Geophysical Research Letters      Published on: 05/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021GL093377

Localized ULF waves; Energetic Elctrons; drift resonance; Time-of-flight Technique; source region; boomerang-shaped stripes; Van Allen Probes

Sustained oxygen spectral gaps and their dynamic evolution in the inner magnetosphere

Abstract Van Allen Probes observations of ion spectra often show a sustained gap within a very narrow energy range throughout the full orbit. To understand their formation mechanism, we statistically investigate the characteristics of the narrow gaps for oxygen ions and find that they are most frequently observed near the noon sector with a peak occurrence rate of over 30\%. The magnetic moment (μ) of the oxygen ions in the gap shows a strong dependence on magnetic local time (MLT), with higher and lower μ in the morning a ...

Yue, Chao; Zhou, Xu-Zhi; Bortnik, Jacob; Zong, Qiu-Gang; Li, Yuxuan; Ren, Jie; Reeves, Geoffrey; Spence, Harlan;

Published by: Journal of Geophysical Research: Space Physics      Published on: 04/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2020JA029092

oxygen spectral gaps; corotational drift resonance; sustained gaps; drainage void; test particle simulations; Van Allen Probes

Pitch Angle Phase Shift in Ring Current Ions Interacting with ULF Waves: Van Allen Probes Observations

Abstract Drift-bounce resonance between ultra-low-frequency (ULF) waves and ring current ions has been widely studied, because of its important role in ring current acceleration and relevant geomagnetic activities. To identify drift-bounce resonance in observations, 180° phase shifts across resonant pitch angle have been proposed as diagnostic signatures. This study, however, presents observations that suggest this criterion may be invalid when phase space density (PSD) distributions vary non-monochromatically with energy. ...

Li, Xing-Yu; Liu, Zhi-Yang; Zong, Qiu-Gang; Zhou, Xu-Zhi; Hao, Yi-Xin; Rankin, Robert; Zhang, Xiao-Xin;

Published by: Journal of Geophysical Research: Space Physics      Published on: 03/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2020JA029025

ring current; ultra-low-frequency waves; drift-bounce resonance; Van Allen Probes

2020

Ring Current Decay During Geomagnetic Storm Recovery Phase: Comparison Between RBSP Observations and Theoretical Modeling

Ring current decay during storm recovery phase may be affected by different loss processes. In this study, we have investigated the lifetimes of ring current ions (H+ and O+) of energies from 1 keV to several hundred keV at L shell from 3 to 6 during the storm recovery phase through a statistical survey. The observational data of 48 geomagnetic storms from March 2013 to May 2019 are collected based on Van Allen Probe observations. We find that (1) the observed lifetimes of H+ and O+ in general increase with L shell and (2) ...

Chen, Ao; Yue, Chao; Chen, HongFei; Zong, Qiugang; Fu, Suiyan; Wang, Yongfu; Ren, Jie;

Published by: Journal of Geophysical Research: Space Physics      Published on: 12/2020

YEAR: 2020     DOI: https://doi.org/10.1029/2020JA028500

charge exchange; lifetime; ring current decay; Van Allen Probes

On the Formation of Wedge-Like Ion Spectral Structures in the Nightside Inner Magnetosphere

Recent observations in the nightside inner magnetosphere have identified a series of wedge-like spectral structures in the energy-time spectrograms of oxygen, helium, and hydrogen ion fluxes. Although the shapes and distributions of these structures have been characterized by case and statistical studies, their formation mechanism remains unclear. Here we utilize a particle tracing model to reproduce the wedge-like structures successively observed by the twin Van Allen Probes. The model suggests that these structures origina ...

Zhou, Xu-Zhi; Ren, Jie; Yang, Fan; Yue, Chao; Zong, Qiu-Gang; Fu, Sui-Yan; Wang, Yongfu;

Published by: Journal of Geophysical Research: Space Physics      Published on: 11/2020

YEAR: 2020     DOI: https://doi.org/10.1029/2020JA028420

wedge-like structure; inner magnetosphere; substorm injection; magnetospheric convection; ring current; magnetotail; Van Allen Probes

Simultaneously Formed Wedge-Like Structures of Different Ion Species Deep in the Inner Magnetosphere

In this study, ion data from the Helium, Oxygen, Proton, and Electron (HOPE) spectrometers onboard Van Allen Probes reveal the existence of wedge-like structures of O+, He+, and H+ ions deep in the inner magnetosphere. The behaviors of the wedge-like structures in terms of temporal evolution, spatial distribution, upper energy limit, as well as dependence on solar wind and different geomagnetic indices are investigated from both event studies of several consecutive orbits on 3 February 2013 and the subsequent statistical ana ...

Ren, Jie; Zong, Q.; Yue, C.; Zhou, X.; Fu, S; Spence, H.; Funsten, H.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 11/2020

YEAR: 2020     DOI: https://doi.org/10.1029/2020JA028192

wedge-like structures; Ring current ions; inner magnetosphere; Substorm Injections; Van Allen Probes

Origin of Electron Boomerang Stripes: Localized ULF Wave-Particle Interactions

Ultralow frequency (ULF) wave-particle interactions play a significant role in the radiation belt dynamic process, during which drift resonance can accelerate and transport energetic electrons in the outer radiation belt. Observations of wave-electron drift resonance are characterized by quasiperiodic straight or “boomerang-shaped” stripes in the pitch angle spectrogram. Here we present an ULF wave event on 1 December 2015, during which both kinds stripes were observed by Van Allen Probes A and B, respectively. Using the ...

Zhao, X.; Hao, Y.; Zong, Q.-G.; Zhou, X.-Z.; Yue, Chao; Chen, X.; Liu, Y.; Blake, J.; Claudepierre, S.; Reeves, G.;

Published by: Geophysical Research Letters      Published on: 07/2020

YEAR: 2020     DOI: https://doi.org/10.1029/2020GL087960

boomerang-shaped stripes; ULF waves; drift resonance; time of flight; Van Allen Probes

The Modulation of Plasma and Waves by Background Electron Density Irregularities in the Inner Magnetosphere

The background cold electron density plays an important role in plasma and wave dynamics. Here, we investigate an event with clear modulation of the particle fluxes and wave intensities by background electron density irregularities based on Van Allen Probes observations. The energies at the peak fluxes of protons and Helium ions of 100 eV to several keV are well correlated with the total electron density variation. Intense electromagnetic ion cyclotron (EMIC) and magnetosonic (MS) waves are simultaneously observed in the hi ...

Yue, Chao; Ma, Qianli; Jun, Chae-Woo; Bortnik, Jacob; Zong, Qiugang; Zhou, Xuzhi; Jang, Eunjin; Reeves, Geoffrey; Spence, Harlan; Wygant, John;

Published by: Geophysical Research Letters      Published on: 07/2020

YEAR: 2020     DOI: https://doi.org/10.1029/2020GL088855

electron density irregularities; electromagnetic ion cyclotron; magnetosonic waves; suprathermal particles; Wave-particle interaction; wave growth rate; Van Allen Probes

A Short-lived Three-Belt Structure for sub-MeV Electrons in the Van Allen Belts: Time Scale and Energy Dependence

In this study we focus on the radiation belt dynamics driven by the geomagnetic storms during September 2017. Besides the long-lasting three-belt structures of ultrarelativistic electrons (>2 MeV, existing for tens of days), which has been studied intensively during the Van Allen Probe era, it is found that magnetospheric electrons of hundreds of keVs can also have three-belt structures at similar L extent during storm time. Measurements of 500–800 keV electrons from MagEIS instrument onboard Van Allen Probes show double- ...

Hao, Y.; Zong, Q.-G.; Zhou, X.-Z.; Zou, H.; Rankin, R.; Sun, Y.; Chen, X.; Liu, Y.; Fu, S; Baker, D.; Spence, H.; Blake, J.; Reeves, G.; Claudepierre, S.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 07/2020

YEAR: 2020     DOI: https://doi.org/10.1029/2020JA028031

storage ring; three-belt structure; hiss wave; electron lifetime; Radial Transport; Van Allen Probes

Simultaneous Observations of Localized and Global Drift Resonance

In this study, we present Van Allen Probe observations showing that seed (hundreds of keV) and core ( 1 MeV) electrons can resonate with ultra-low-frequency (ULF) wave modes with distinctive m values simultaneously. An unusual electron energy spectrogram with double-banded resonant structure was recorded by energetic particle, composition, and thermal plasma (ECT)-magnetic electron ion spectrometer (MagEIS) and, meanwhile, boomerang stripes in pitch angle spectrogram appeared at the lower energy band. A localized drift reson ...

Hao, Y.; Zhao, X.; Zong, Q.-G.; Zhou, X.-Z.; Rankin, R.; Chen, X.; Liu, Y.; Fu, S; Blake, J.; Reeves, G.; Claudepierre, S.;

Published by: Geophysical Research Letters      Published on: 05/2020

YEAR: 2020     DOI: https://doi.org/10.1029/2020GL088019

drift resonance; ULF waves; Radiation Belt Dynamics; boomerang stripes; azimuthal wave number; multiple resonances; Van Allen Probes

The Dynamics of the Inner Boundary of the Outer Radiation Belt During Geomagnetic Storms

Abstract We investigate the shapes of the inner boundary of the outer radiation belt during different geomagnetic storm phases using energetic electron observations from Van Allen Probes. The case of two consecutive but isolated storms in April 2016 shows that (a) the inner boundary, as a function of L shell and energy, exhibits a “V-shaped” form with the energetic electrons showing a kappa-like energy spectrum (electron flux steeply falling with increasing energies), whereas it is in a “S-shaped” form as the energet ...

Shi, Xiaofei; Ren, Jie; Zong, Q.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 04/2020

YEAR: 2020     DOI: 10.1029/2019JA027309

Van Allen Probes

The Dynamics of the Inner Boundary of the Outer Radiation Belt During Geomagnetic Storms

We investigate the shapes of the inner boundary of the outer radiation belt during different geomagnetic storm phases using energetic electron observations from Van Allen Probes. The case of two consecutive but isolated storms in April 2016 shows that (a) the inner boundary, as a function of L shell and energy, exhibits a “V-shaped” form with the energetic electrons showing a kappa-like energy spectrum (electron flux steeply falling with increasing energies), whereas it is in a “S-shaped” form as the energetic electr ...

Shi, Xiaofei; Ren, Jie; Zong, Q.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 04/2020

YEAR: 2020     DOI: https://doi.org/10.1029/2019JA027309

Van Allen Probes

Episodic Occurrence of Field-Aligned Energetic Ions on the Dayside

The tens of kiloelectron volt ions observed in the ring current region at L ~ 3\textendash7 generally have pancake pitch angle distributions, that is, peaked at 90\textdegree. However, in this study, by using the Van Allen Probe observations on the dayside, unexpectedly, we have found that about 5\% time, protons with energies of ~30 to 50 keV show two distinct populations, having an additional field-aligned population overlapping with the original pancake population. The newly appearing field-aligned populations have higher ...

Yue, Chao; Bortnik, Jacob; Zou, Shasha; Nishimura, Yukitoshi; Foster, John; Coppeans, Thomas; Ma, Qianli; Zong, Qiugang; Hull, A.; Henderson, Mike; Reeves, Geoffrey; Spence, Harlan;

Published by: Geophysical Research Letters      Published on: 01/2020

YEAR: 2020     DOI: 10.1029/2019GL086384

Van Allen Probes

2019

Cold Plasmaspheric Electrons Affected by ULF Waves in the Inner Magnetosphere: A Van Allen Probes Statistical Study

Six years of Van Allen Probes data are used to investigate cold plasmaspheric electrons affected by ultralow-frequency (ULF) waves in the inner magnetosphere (L<7) including spatial distributions, occurrence conditions, and resonant energy range. Events exhibit a global distribution within L= 4\textendash7 but preferentially occur at L\~5.5\textendash7 in the dayside, while there is higher occurrence rate in the duskside than dawnside. They can occur under different geomagnetic activities and solar wind velocities (VS), but ...

Ren, Jie; Zong, Q.; Zhou, X.; Spence, H.; Funsten, H.; Wygant, J.; Rankin, R.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 10/2019

YEAR: 2019     DOI: 10.1029/2019JA027009

Cold plasmaspheric electrons; drift-bounce resonance; ULF waves; Van Allen Probes; Wave-particle interaction

2018

Nonlinear drift resonance between charged particles and ultra-low frequency waves: Theory and Observations

In Earth\textquoterights inner magnetosphere, electromagnetic waves in the ultra-low frequency (ULF) range play an important role in accelerating and diffusing charged particles via drift resonance. In conventional drift-resonance theory, linearization is applied under the assumption of weak wave-particle energy exchange so particle trajectories are unperturbed. For ULF waves with larger amplitudes and/or durations, however, the conventional theory becomes inaccurate since particle trajectories are strongly perturbed. Here, ...

Li, Li; Zhou, Xu-Zhi; Omura, Yoshiharu; Wang, Zi-Han; Zong, Qiu-Gang; Liu, Ying; Hao, Yi-Xin; Fu, Sui-Yan; Kivelson, Margaret; Rankin, Robert; Claudepierre, Seth; Wygant, John;

Published by: Geophysical Research Letters      Published on: 08/2018

YEAR: 2018     DOI: 10.1029/2018GL079038

drift resonance; nonlinear process; Particle acceleration; Radiation belts; ULF waves; Van Allen Probes; wave-particle interactions

A comparative study of ULF waves\textquoteright role in the dynamics of charged particles in the plasmasphere: Van Allen Probes observation

By analyzing observations from Van Allen Probes in its inbound and outbound orbits, we present evidence of coherent enhancement of cold plasmaspheric electrons and ions due to drift-bounce resonance with ULF waves. From 18:00 UT on 28 May 2017 to 10:00 UT on 29 May 2017, newly formed poloidal mode standing ULF waves with significant electric field oscillations were observed in two consecutive orbits when Probe B was travelling inbound. In contrast to observations during outbound orbits, the cold (< 150 eV) electorns measured ...

Ren, Jie; Zong, Qiu-Gang; Miyoshi, Yoshizumi; Rankin, Robert; Spence, Harlan; Funsten, Herbert; Wygant, John; Kletzing, Craig;

Published by: Journal of Geophysical Research: Space Physics      Published on: 06/2018

YEAR: 2018     DOI: 10.1029/2018JA025255

Cold plasmaspheric electrons acceleration; Drfit-bounce resonance; Modification of electron and ion density profile; Substorm activities; ULF waves; Van Allen Probes

Poloidal mode wave-particle interactions inferred from Van Allen Probes and CARISMA ground-based observations

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 Alfv\ en waves detected near the magnetic equator at L\~5.7. Results obtained from simulations reproduce important features of the observations, including a substantial e ...

Wang, C.; Rankin, R.; Wang, Y.; Zong, Q.-G.; Zhou, X.; Takahashi, K.; Marchand, R.; Degeling, A.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 05/2018

YEAR: 2018     DOI: 10.1029/2017JA025123

ULF wave; drift-resonant; test particle simulation; Van Allen Probes

The Radial Propagation Characteristics of the Injection Front: A Statistical Study Based on BD-IES and Van Allen Probes Observations

Electron flux measurements outside geosynchronous orbit (GSO) obtained by the BeiDa Imaging Electron Spectrometer instrument onboard a 55 degrees-inclined GSO satellite, and inside GSO obtained by the Van Allen Probes are analyzed to investigate the temporal and spatial evolutions of the substorm injection region. In one year data started from October 2015, 63 injection events are identified. Firstly, our study shows that the injection signatures can be detected in a large radial extent in one single event, for example, from ...

Liu, Z; Zong, Q.-G.; Hao, Y.; Liu, Y.; Chen, X.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 02/2018

YEAR: 2018     DOI: 10.1002/2018JA025185

earthward propagation; radial propagation speed; substorm injection; tailward propagation; upper-cutoff magnetic moment; Van Allen Probes

2017

Low-energy (< 200 eV) electron acceleration by ULF waves in the plasmaspheric boundary layer: Van Allen Probes observation

We report observational evidence of cold plamsmaspheric electron (< 200 eV) acceleration by ultra-low-frequency (ULF) waves in the plasmaspheric boundary layer on 10 September 2015. Strongly enhanced cold electron fluxes in the energy spectrogram were observed along with second harmonic mode waves with a period of about 1 minute which lasted several hours during two consecutive Van Allen Probe B orbits. Cold electron (<200 eV) and energetic proton (10-20 keV) bi-directional pitch angle signatures observed during the event ar ...

Ren, Jie; Zong, Q.; Miyoshi, Y.; Zhou, X.; Wang, Y.; Rankin, R.; Yue, C.; Spence, H.; Funsten, H.; Wygant, J.; Kletzing, C.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 08/2017

YEAR: 2017     DOI: 10.1002/2017JA024316

Cold plasmaspheric electrons; drift-bounce resonance; Plasma instability; Plasmaspheric boundary layer; Substorm-injected protons; ULF waves; Van Allen Probes

Relativistic electron dynamics produced by azimuthally localized poloidal mode ULF waves: Boomerang-shaped pitch angle evolutions

We present an analysis of \textquotedblleftboomerang-shaped\textquotedblright pitch angle evolutions of outer radiation belt relativistic electrons observed by the Van Allen Probes after the passage of an interplanetary shock on June 7th, 2014. The flux at different pitch angles is modulated by Pc5 waves, with equatorially mirroring electrons reaching the satellite first. For 90o pitch angle electrons, the phase change of the flux modulations across energy exceeds 180o, and increasingly tilts with time. Using estimates of th ...

Hao, Y.; Zong, Q.-G.; Zhou, X.-Z.; Rankin, R.; Chen, X.; Liu, Y.; Fu, S; Spence, H.; Blake, J.; Reeves, G.;

Published by: Geophysical Research Letters      Published on: 07/2017

YEAR: 2017     DOI: 10.1002/2017GL074006

drift resonance; interplanetary shock; localized waves; Radiation belts; ULF waves; Van Allen Probes; Wave-particle interaction

Statistical study of the storm-time radiation belt evolution during Van Allen Probes era: CME- versus CIR-driven storms

CME- or CIR-driven storms can change the electron distributions in the radiation belt dramatically, which can in turn affect the spacecraft in this region or induce geomagnetic effects. The Van Allen Probes twin spacecraft, launched on 30 August 2012, orbit near the equatorial plane and across a wide range of L* with apogee at 5.8 RE and perigee at 620 km. Electron data from Van Allen Probes MagEIS and REPT instruments have been binned every six hours at L*=3 (defined as 2.5

Shen, Xiao-Chen; Hudson, Mary; Jaynes, Allison; Shi, Quanqi; Tian, Anmin; Claudepierre, Seth; Qin, Mu-Rong; Zong, Qiu-Gang; Sun, Wei-Jie;

Published by: Journal of Geophysical Research: Space Physics      Published on: 07/2017

YEAR: 2017     DOI: 10.1002/2017JA024100

CIR-driven storm; CME-driven storm; outer radiation belt; Van Allen Probes

Van Allen Probes observation of a 360\textdegree phase shift in the flux modulation of injected electrons by ULF waves

We present Van Allen Probe observation of drift-resonance interaction between energetic electrons and ultralow frequency (ULF) waves on 29 October 2013. Oscillations in electron flux were observed at the period of \~450 s, which is also the dominant period of the observed ULF magnetic pulsations. The phase shift of the electron fluxes (\~50 to 150 keV) across the estimated resonant energy (\~104 keV) is \~360\textdegree. This phase relationship is different from the characteristic 180\textdegree phase shift as expected from ...

Chen, X.-R.; Zong, Q.-G.; Zhou, X.-Z.; Blake, Bernard; Wygant, J.; Kletzing, C.;

Published by: Geophysical Research Letters      Published on: 02/2017

YEAR: 2017     DOI: 10.1002/2016GL071252

drift resonance; injection; PSD gradient; ULF waves; Van Allen Probes

2016

Van Allen Probes observation of a 360\textdegree phase shift in the flux modulation of injected electrons by ULF waves

We present Van Allen Probe observation of drift-resonance interaction between energetic electrons and ultra-low frequency (ULF) waves on October 29, 2013. Oscillations in electron flux were observed at the period of \~450s, which is also the dominant period of the observed ULF magnetic pulsations. The phase shift of the electron fluxes (\~50 to 150 keV) across the estimated resonant energy (\~104 keV) is \~360\textdegree. This phase relationship is different from the characteristic 180\textdegree phase shift as expected from ...

Chen, X.-R.; Zong, Q.-G.; Zhou, X.-Z.; Blake, Bernard; Wygant, John; Kletzing, Craig;

Published by: Geophysical Research Letters      Published on: 12/2016

YEAR: 2016     DOI: 10.1002/2016GL071252

drift-resonance; injection; PSD gradient; ULF waves; Van Allen Probes

Rapid enhancement of low-energy (<100 eV) ion flux in response to interplanetary shocks based on two Van Allen Probes case studies: Implications for source regions and heating mechanisms

Interactions between interplanetary (IP) shocks and the Earth\textquoterights magnetosphere manifest many important space physics phenomena including low-energy ion flux enhancements and particle acceleration. In order to investigate the mechanisms driving shock-induced enhancement of low-energy ion flux, we have examined two IP shock events that occurred when the Van Allen Probes were located near the equator while ionospheric and ground observations were available around the spacecraft footprints. We have found that, assoc ...

Yue, Chao; Li, Wen; Nishimura, Yukitoshi; Zong, Qiugang; Ma, Qianli; Bortnik, Jacob; Thorne, Richard; Reeves, Geoffrey; Spence, Harlan; Kletzing, Craig; Wygant, John; Nicolls, Michael;

Published by: Journal of Geophysical Research: Space Physics      Published on: 06/2016

YEAR: 2016     DOI: 10.1002/2016JA022808

adiabatic accelerations; enhancement of low-energy ion flux; ionospheric ion outflows; response to IP shocks; Van Allen Probes

Compressional ULF wave modulation of energetic particles in the inner magnetosphere

We present Van Allen Probes observations of modulations in the flux of very energetic electrons up to a few MeV and protons between 1200 - 1400 UT on February 19th, 2014. During this event the spacecraft were in the dayside magnetosphere at L*≈5.5. The modulations extended across a wide range of particle energies, from 79.80 keV to 2.85 MeV for electrons and from 82.85 keV to 636.18 keV for protons. The fluxes of π/2 pitch angle particles were observed to attain maximum values simultaneously with the ULF compressional mag ...

Liu, H.; Zong, Q.-G.; Zhou, X.-Z.; Fu, S; Rankin, R.; Wang, L.-H.; Yuan, C.; Wang, Y.; Baker, D.; Blake, J.; Kletzing, C.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 05/2016

YEAR: 2016     DOI: 10.1002/2016JA022706

Compressional ULF wave; energetic particles; Magnetosphere; Mirror effect; Modulation; relativistic electrons; Van Allen Probes

Electron dropout echoes induced by interplanetary shock: Van Allen Probes observations

On 23 November 2012, a sudden dropout of the relativistic electron flux was observed after an interplanetary shock arrival. The dropout peaks at \~1MeV and more than 80\% of the electrons disappeared from the drift shell. Van Allen twin Probes observed a sharp electron flux dropout with clear energy dispersion signals. The repeating flux dropout and recovery signatures, or \textquotedblleftdropout echoes\textquotedblright, constitute a new phenomenon referred to as a \textquotedblleftdrifting electron dropout\textquotedblrig ...

Hao, Y.; Zong, Q.-G.; Zhou, X.-Z.; Fu, S; Rankin, R.; Yuan, C.-J.; T. Y. Lui, A.; Spence, H.; Blake, J.; Baker, D.; Reeves, G.;

Published by: Geophysical Research Letters      Published on: 05/2016

YEAR: 2016     DOI: 10.1002/2016GL069140

Drift shell splitting; electron dropout echo; energetic particle; interplanetary shock; magnetopause shadowing; solar wind-magnetospheric coupling; Van Allen Probes

Structure and Evolution of Electron "Zebra Stripes" in the Inner Radiation Belt

Zebra stripes\textquotedblright are newly found energetic electron energy-spatial (L shell) distributed structure with an energy between tens to a few hundreds keV in the inner radiation belt. Using high-quality measurements of electron fluxes from Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) on board the twin Van Allen Probes, we carry out case and statistical studies from April 2013 to April 2014 to study the structural and evolutionary characteristics of zebra stripes below L = 3. It is revealed that t ...

Liu, Y.; Zong, Q.-G.; Zhou, X.-Z.; Foster, J.; Rankin, R.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 05/2016

YEAR: 2016     DOI: 10.1002/2015JA022077

electric field; energetic electrons; particle dynamic; Radiation belt; Van Allen Probes; zebra stripes

Charged particle behavior in the growth and damping stages of ultralow frequency waves: theory and Van Allen Probes observations

Ultralow frequency (ULF) electromagnetic waves in Earth\textquoterights magnetosphere can accelerate charged particles via a process called drift resonance. In the conventional drift-resonance theory, a default assumption is that the wave growth rate is time-independent, positive, and extremely small. However, this is not the case for ULF waves in the real magnetosphere. The ULF waves must have experienced an earlier growth stage when their energy was taken from external and/or internal sources, and as time proceeds the wave ...

Zhou, Xu-Zhi; Wang, Zi-Han; Zong, Qiu-Gang; Rankin, Robert; Kivelson, Margaret; Chen, Xing-Ran; Blake, Bernard; Wygant, John; Kletzing, Craig;

Published by: Journal of Geophysical Research: Space Physics      Published on: 03/2016

YEAR: 2016     DOI: 10.1002/2016JA022447

drift resonance; Radiation belt; ULF waves; Van Allen Probes; wave growth and damping; Wave-particle interaction

2015

Ultra-low-frequency wave-driven diffusion of radiation belt relativistic electrons

Van Allen radiation belts are typically two zones of energetic particles encircling the Earth separated by the slot region. How the outer radiation belt electrons are accelerated to relativistic energies remains an unanswered question. Recent studies have presented compelling evidence for the local acceleration by very-low-frequency (VLF) chorus waves. However, there has been a competing theory to the local acceleration, radial diffusion by ultra-low-frequency (ULF) waves, whose importance has not yet been determined definit ...

Su, Zhenpeng; Zhu, Hui; Xiao, Fuliang; Zong, Q.-G.; Zhou, X.-Z.; Zheng, Huinan; Wang, Yuming; Wang, Shui; Hao, Y.-X.; Gao, Zhonglei; He, Zhaoguo; Baker, D.; Spence, H.; Reeves, G.; Blake, J.; Wygant, J.;

Published by: Nature Communications      Published on: 12/2015

YEAR: 2015     DOI: 10.1038/ncomms10096

Van Allen Probes

Imprints of impulse-excited hydromagnetic waves on electrons in the Van Allen radiation belts

Ultralow frequency electromagnetic oscillations, interpreted as standing hydromagnetic waves in the magnetosphere, are a major energy source that accelerates electrons to relativistic energies in the Van Allen radiation belt. Electrons can rapidly gain energy from the waves when they resonate via a process called drift resonance, which is observationally characterized by energy-dependent phase differences between electron flux and electromagnetic oscillations. Such dependence has been recently observed and interpreted as spa ...

Zhou, Xu-Zhi; Wang, Zi-Han; Zong, Qiu-Gang; Claudepierre, Seth; Mann, Ian; Kivelson, Margaret; Angelopoulos, Vassilis; Hao, Yi-Xin; Wang, Yong-Fu; Pu, Zu-Yin;

Published by: Geophysical Research Letters      Published on: 08/2015

YEAR: 2015     DOI: 10.1002/grl.v42.1510.1002/2015GL064988

drift resonance; Radiation belt; ULF waves; Van Allen Probes; wave growth; Wave-particle interaction

Fast damping of ultralow frequency waves excited by interplanetary shocks in the magnetosphere

Analysis of Cluster spacecraft data shows that intense ultralow frequency (ULF) waves in the inner magnetosphere can be excited by the impact of interplanetary shocks and solar wind dynamic pressure variations. The observations reveal that such waves can be damped away rapidly in a few tens of minutes. Here we examine mechanisms of ULF wave damping for two interplanetary shocks observed by Cluster on 7 November 2004 and 30 August 2001. The mechanisms considered are ionospheric joule heating, Landau damping, and waveguide ene ...

Wang, Chengrui; Rankin, Robert; Zong, Qiugang;

Published by: Journal of Geophysical Research: Space Physics      Published on: 03/2015

YEAR: 2015     DOI: 10.1002/2014JA020761

drift-bounce resonance; Landau damping; ULF wave

2014

Quantifying the relative contributions of substorm injections and chorus waves to the rapid outward extension of electron radiation belt

We study the rapid outward extension of the electron radiation belt on a timescale of several hours during three events observed by RBSP and THEMIS satellites, and particularly quantify the contributions of substorm injections and chorus waves to the electron flux enhancement near the outer boundary of radiation belt. A comprehensive analysis including both observations and simulations is performed for the first event on 26 May 2013. The outer boundary of electron radiation belt moved from L = 5.5 to L > 6.07 over about 6 ho ...

Su, Zhenpeng; Zhu, Hui; Xiao, Fuliang; Zheng, Huinan; Wang, Yuming; Zong, Q.-G.; He, Zhaoguo; Shen, Chao; Zhang, Min; Wang, Shui; Kletzing, C.; Kurth, W.; Hospodarsky, G.; Spence, H.; Reeves, G.; Funsten, H.; Blake, J.; Baker, D.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 12/2014

YEAR: 2014     DOI: 10.1002/2014JA020709

Chorus wave; Electron acceleration; Radiation belt; substorm injection; Van Allen Probes; Wave-particle interaction

Modeling radiation belt electron acceleration by ULF fast mode waves, launched by solar wind dynamic pressure fluctuations

We investigate the magnetospheric MHD and energetic electron response to a Storm Sudden Commencement (SSC) and subsequent magnetopause buffeting, focusing on an interval following an SSC event on 25 November 2001. We find that the electron flux signatures observed by LANL, Cluster, and GOES spacecraft during this event can largely be reproduced using an advective kinetic model for electron phase space density, using externally prescribed electromagnetic field inputs, (herein described as a \textquotedbllefttest-kinetic model ...

Degeling, A.; Rankin, R.; Zong, Q.-G.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 11/2014

YEAR: 2014     DOI: 10.1002/2013JA019672

adiabatic electron transport; magnetopause buffeting; Radiation belts; ULF waves

Interactions of energetic electrons with ULF waves triggered by interplanetary shock: Van Allen Probes observations in the magnetotail

We present in situ observations of a shock-induced substorm-like event on 13 April 2013 observed by the newly launched Van Allen twin probes. Substorm-like electron injections with energy of 30\textendash500 keV were observed in the region from L\~5.2 to 5.5 immediately after the shock arrival (followed by energetic electron drift echoes). Meanwhile, the electron flux was clearly and strongly varying on the ULF wave time scale. It is found that both toroidal and poloidal mode ULF waves with a period of 150 s emerged followin ...

Hao, Y.; Zong, Q.-G.; Wang, Y.; Zhou, X.-Z.; Zhang, Hui; Fu, S; Pu, Z; Spence, H.; Blake, J.; Bonnell, J.; Wygant, J.; Kletzing, C.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 10/2014

YEAR: 2014     DOI: 10.1002/2014JA020023

energetic particles; interplanetary shock; magnetotail ULF wave; poloidal and toroidal mode; Van Allen Probes; wave-particle interactions



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