Bibliography



Found 69 entries in the Bibliography.


Showing entries from 1 through 50


2021

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;

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

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

A comparative study on the distributions of incoherent and coherent plasmaspheric hiss

Abstract We perform a comparative study on the distributions of incoherent and coherent plasmaspheric hiss, based on the Van Allen Probe data. The statistics show that incoherent hiss ( ∼10–20 pT) is widely distributed in dayside plasmasphere, with peak frequencies below 500 Hz; intense coherent hiss (amplitudes up to 80 pT) occurs in outer plasmasphere of L > 4 (L denotes the L-shell.), whose frequency increases with ambient magnetic field significantly. The Poynting flux analysis indicates that incoherent hiss generall ...

He, Zhaoguo; Yu, Jiang; Li, Kun; Liu, Nigang; Chen, Zewen; Cui, Jun;

YEAR: 2021     DOI: https://doi.org/10.1029/2021GL092902

Van Allen Probes

2020

Statistical Distribution of Bifurcation of Earth s Inner Energetic Electron Belt at tens of keV

We present a survey of the bifurcation of the Earth s energetic electron belt (tens of keV) using 6-year measurements from Van Allen Probes. The inner energetic electron belt usually presents one-peak radial structure with high flux intensity at L < ∼2.5, which however can be bifurcated to exhibit a double-peak radial structure. By automatically identifying the events of bifurcation based on RBSPICE data, we find that the bifurcation is mostly observed at ∼30–100 keV with a local flux minimum at L=∼2.0–∼2.3 under ...

Hua, Man; Ni, Binbin; Li, Wen; Ma, Qianli; Gu, Xudong; Fu, Song; Cao, Xing; Guo, YingJie; Liu, Yangxizi;

YEAR: 2020     DOI: https://doi.org/10.1029/2020GL091242

Inner electron radiation belt; Flux bifurcation; VLF transmitter waves; Statistical distribution; Van Allen Probes

Correlated Observation on Global Distributions of Magnetosonic Waves and Proton Rings in the Radiation Belts

Fast magnetosonic (MS) waves are excited by the ring distribution of energetic protons preferably when the ring velocity (VR) is within a factor of 2 above or below the local Alfvén speed (VA). Here we examine the global distributions of MS waves and proton rings with 0.5VA ≤ VR ≤ 2VA based on 64 months (from October 25, 2012 to February 28, 2018) of Van Allen Probes observations. The statistical results show that MS waves are present over a broad region of L = 1.2–6.0 and 00–24 magnetic local time (MLT), wit ...

Zhou, Qinghua; Jiang, Zheng; Yang, Chang; He, Yihua; Liu, Si; Xiao, Fuliang;

YEAR: 2020     DOI: https://doi.org/10.1029/2020JA028354

Fast Magnetosonic Waves; global occurrences; proton ring distribution; Radiation belt; Van Allen Probe observation; Van Allen Probes

Global Propagation of Magnetospheric Pc5 ULF Waves Driven by Foreshock Transients

Pc5 (2–7 mHz) ultralow frequency (ULF) waves play a significant role in resonating with particles and transferring energy in the coupled magnetospheric and ionospheric system. Recent studies found that Pc5 ULF waves can be triggered by foreshock transients which can perturb the magnetopause through dynamic pressure variation. However, whether foreshock transient-driven Pc5 ULF waves are geoeffective and can propagate globally is still poorly understood. In this study, we take advantage of the conjunction between in situ (b ...

Wang, Boyi; Liu, Terry; Nishimura, Yukitoshi; Zhang, Hui; Hartinger, Michael; Shi, Xueling; Ma, Qianli; Angelopoulos, Vassilis; Frey, Harald;

YEAR: 2020     DOI: https://doi.org/10.1029/2020JA028411

ULF wave; Field line resonance; wave number; global; THEMIS; aurora; Van Allen Probes

On the loss mechanisms of radiation belt electron dropouts during the 12 September 2014 geomagnetic storm

Radiation belt electron dropouts indicate electron flux decay to the background level during geomagnetic storms, which is commonly attributed to the effects of wave-induced pitch angle scattering and magnetopause shadowing. To investigate the loss mechanisms of radiation belt electron dropouts triggered by a solar wind dynamic pressure pulse event on 12 September 2014, we comprehensively analyzed the particle and wave measurements from Van Allen Probes. The dropout event was divided into three periods: before the storm, the ...

Ma, Xin; Xiang, Zheng; Ni, Binbin; Fu, Song; Cao, Xing; Hua, Man; Guo, DeYu; Guo, YingJie; Gu, Xudong; Liu, ZeYuan; Zhu, Qi;

YEAR: 2020     DOI: https://doi.org/10.26464/epp2020060

radiation belt electron flux dropouts; Geomagnetic storm; electron phase space density; magnetopause shadowing; wave–particle interactions; Van Allen Probes

Relation Between Shock-Related Impulse and Subsequent ULF Wave in the Earth s Magnetosphere

The generation of Pc4-5 ultralow frequency (ULF) waves after interplanetary shock-induced electric field impulses in the Earth s magnetosphere is studied using Van Allen Probes measurements by investigating the relationship between the first impulses and subsequent resonant ULF waves. In the dayside, the relevant time scales of the first impulse is correlated better with local Alfvén speed than with local eigenfrequency, implying that the temporal scale of the first impulse is more likely related to fast-mode wave propagati ...

Zhang, Dianjun; Liu, Wenlong; Li, Xinlin; Sarris, Theodore; Wang, Yongfu; Xiao, Chao; Zhang, Zhao; Wygant, John;

YEAR: 2020     DOI: https://doi.org/10.1029/2020GL090027

ULF wave; interplanetary shock; Magnetosphere; Field line resonance; electric field; wave excitation; Van Allen Probes

Suprathermal Electron Evolution Under the Competition Between Plasmaspheric Plume Hiss Wave Heating and Collisional Cooling

Suprathermal electrons are a major heat source of ionospheric plasma. How the suprathermal electrons evolve during their bounces inside the plasmasphere is a fundamental question for the magnetosphere-ionosphere coupling. On the basis of Van Allen Probes observations and quasi-linear simulations, we present here the first quantitative study on the evolution of suprathermal electrons under the competition between Landau heating by whistler mode hiss waves and Coulomb collisional cooling by background plasma inside a plasmasph ...

Wang, Zhongshan; Su, Zhenpeng; Liu, Nigang; Dai, Guyue; Zheng, Huinan; Wang, Yuming; Wang, Shui;

YEAR: 2020     DOI: https://doi.org/10.1029/2020GL089649

magnetosphere-ionosphere coupling; whistler mode hiss waves; Landau resonance; Coulomb collisions; suprathermal electrons; ring current; Van Allen Probes

Can Solar Wind Decompressive Discontinuities Suppress Magnetospheric Electromagnetic Ion Cyclotron Waves Associated With Fresh Proton Injections?

Electromagnetic ion cyclotron (EMIC) waves play an important role in the energy transfer among particles of different energies and species in the magnetosphere, whose drivers have been commonly recognized as solar wind compressions and storm/substorm proton injections. However, how the solar wind decompressions related to frequently occurring discontinuities compete with the proton injections in the evolution of EMIC waves has been rarely investigated. Here we present a complete end-to-end observation by Wind, THEMIS, and Va ...

Liu, Nigang; Su, Zhenpeng; Gao, Zhonglei; Zheng, Huinan; Wang, Yuming; Wang, Shui;

YEAR: 2020     DOI: https://doi.org/10.1029/2020GL090296

EMIC waves; solar wind discontinuity; storm/substorm injection; wave generation; adiabatic deceleration; inner magnetosphere; 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.;

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

boomerang-shaped stripes; ULF waves; drift resonance; time of flight; 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.; . Y. Fu, S; Baker, D.; Spence, H.; Blake, J.; Reeves, G.; Claudepierre, S.;

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

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

Simulations of Electron Flux Oscillations as Observed by MagEIS in Response to Broadband ULF Waves

Coherent electron flux oscillations of hundreds of keV are often observed by the Van Allen Probes in the magnetosphere during quiet times in association with ultralow frequency (ULF) waves. They are observed in the form of periodic flux fluctuations, with a drift frequency that is energy dependent, but are not associated with drift echoes following storm- or substorm-related energetic particle injections. Instead, they are associated with the resonant interaction of electrons with ULF waves and are an indication of ongoing e ...

Sarris, Theodore; Li, Xinlin; Temerin, Michael; Zhao, Hong; Khoo, Leng; Turner, Drew; Liu, Wenlong; Claudepierre, Seth;

YEAR: 2020     DOI: https://doi.org/10.1029/2020JA027798

electron flux oscillations; ULF waves; Magnetosphere; Radiation belts; radial diffusion; particle tracing simulations; 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.; . Y. Fu, S; Blake, J.; Reeves, G.; Claudepierre, S.;

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 Relation Between Electron Cyclotron Harmonic Waves and Plasmapause: Case and Statistical Studies

Abstract Observationally, electron cyclotron harmonic (ECH) waves are often terminated at the outer boundary of the plasmasphere boundary layer (PBL, i.e., plasmapause). Physics of this empirical relation is not well established. In this study, two categories of ECH waves are shown by their different behaviors near PBL. For Category I, all bands of ECH waves terminate at PBL because the density ratio (nh/nc) between hot and cold electrons decreases dramatically across PBL. For Category II, ECH waves, especially the lower har ...

Liu, Xu; Chen, Lunjin; Xia, Zhiyang;

YEAR: 2020     DOI: 10.1029/2020GL087365

two types of ECH wave; Plasmapause; instability; excitation and attenuation mechanism; statistical characteristics of two types of ECH wave; Van Allen Probes

The Relation Between Electron Cyclotron Harmonic Waves and Plasmapause: Case and Statistical Studies

Observationally, electron cyclotron harmonic (ECH) waves are often terminated at the outer boundary of the plasmasphere boundary layer (PBL, i.e., plasmapause). Physics of this empirical relation is not well established. In this study, two categories of ECH waves are shown by their different behaviors near PBL. For Category I, all bands of ECH waves terminate at PBL because the density ratio (nh/nc) between hot and cold electrons decreases dramatically across PBL. For Category II, ECH waves, especially the lower harmonic ban ...

Liu, Xu; Chen, Lunjin; Xia, Zhiyang;

YEAR: 2020     DOI: https://doi.org/10.1029/2020GL087365

two types of ECH wave; Plasmapause; instability; excitation and attenuation mechanism; statistical characteristics of two types of ECH wave; Van Allen Probes

Global Simulation of Electron Cyclotron Harmonic Wave Instability in a Storm-Time Magnetosphere

Abstract Electron cyclotron harmonic (ECH) waves are electrostatic emissions between the ECHs and play a dominant role for precipitating energetic electrons in the magnetotail. Statistically, the ECH wave intensity is stronger at nightside and dawnside than at dayside and duskside. In this study, we, for the first time, simulate the global ECH wave evolution during a geomagnetic storm event using Ring current Atmosphere interactions Model with Self-Consistent Magnetic field (RAM-SCB) combined with a linear growth rate solver ...

Liu, Xu; Chen, Lunjin; Engel, Miles; Jordanova, Vania;

YEAR: 2020     DOI: https://doi.org/10.1029/2019GL086368

ECH wave global instability; RAM-SCB model; Geomagnetic storm; Van Allen Probes

Comprehensive Observations of Substorm-Enhanced Plasmaspheric Hiss Generation, Propagation, and Dissipation

Plasmaspheric hiss is an important whistler-mode emission shaping the Van Allen radiation belt environment. How the plasmaspheric hiss waves are generated, propagate, and dissipate remains under intense debate. With the five spacecraft of Van Allen Probes, Exploration of energization and Radiation in Geospace (Arase), and Geostationary Operational Environmental Satellites missions at widely spaced locations, we present here the first comprehensive observations of hiss waves growing from the substorm-injected electron instabi ...

Liu, Nigang; Su, Zhenpeng; Gao, Zhonglei; Zheng, Huinan; Wang, Yuming; Wang, Shui; Miyoshi, Yoshizumi; Shinohara, Iku; Kasahara, Yoshiya; Tsuchiya, Fuminori; Kumamoto, Atsushi; Matsuda, Shoya; Shoji, Masafumi; Mitani, Takefumi; Takashima, Takeshi; Kazama, Yoichi; Wang, Bo-Jhou; Wang, Shiang-Yu; Jun, Chae-Woo; Chang, Tzu-Fang; W. Y. Tam, Sunny; Kasahara, Satoshi; Yokota, Shoichiro; Keika, Kunihiro; Hori, Tomoaki; Matsuoka, Ayako;

YEAR: 2020     DOI: 10.1029/2019GL086040

plasmasphere; Plasmaspheric Hiss; Radiation belt; Van Allen Probes; Wave Dissipation; wave generation; wave propagation

Comprehensive Observations of Substorm-Enhanced Plasmaspheric Hiss Generation, Propagation, and Dissipation

Abstract Plasmaspheric hiss is an important whistler-mode emission shaping the Van Allen radiation belt environment. How the plasmaspheric hiss waves are generated, propagate, and dissipate remains under intense debate. With the five spacecraft of Van Allen Probes, Exploration of energization and Radiation in Geospace (Arase), and Geostationary Operational Environmental Satellites missions at widely spaced locations, we present here the first comprehensive observations of hiss waves growing from the substorm-injected electro ...

Liu, Nigang; Su, Zhenpeng; Gao, Zhonglei; Zheng, Huinan; Wang, Yuming; Wang, Shui; Miyoshi, Yoshizumi; Shinohara, Iku; Kasahara, Yoshiya; Tsuchiya, Fuminori; Kumamoto, Atsushi; Matsuda, Shoya; Shoji, Masafumi; Mitani, Takefumi; Takashima, Takeshi; Kazama, Yoichi; Wang, Bo-Jhou; Wang, Shiang-Yu; Jun, Chae-Woo; Chang, Tzu-Fang; W. Y. Tam, Sunny; Kasahara, Satoshi; Yokota, Shoichiro; Keika, Kunihiro; Hori, Tomoaki; Matsuoka, Ayako;

YEAR: 2020     DOI: 10.1029/2019GL086040

Plasmaspheric Hiss; Radiation belt; plasmasphere; wave generation; wave propagation; Wave Dissipation

2019

Identifying STEVE\textquoterights Magnetospheric Driver Using Conjugate Observations in the Magnetosphere and on the Ground

The magnetospheric driver of strong thermal emission velocity enhancement (STEVE) is investigated using conjugate observations when Van Allen Probes\textquoteright footprint directly crossed both STEVE and stable red aurora (SAR) arc. In the ionosphere, STEVE is associated with subauroral ion drift features, including electron temperature peak, density gradient, and westward ion flow. The SAR arc at lower latitudes corresponds to regions inside the plasmapause with isotropic plasma heating, which causes redline-only SAR emis ...

Chu, Xiangning; Malaspina, David; Gallardo-Lacourt, Bea; Liang, Jun; Andersson, Laila; Ma, Qianli; Artemyev, Anton; Liu, Jiang; Ergun, Robert; Thaller, Scott; Akbari, Hassanali; Zhao, Hong; Larsen, Brian; Reeves, Geoffrey; Wygant, John; Breneman, Aaron; Tian, Sheng; Connors, Martin; Donovan, Eric; Archer, William; MacDonald, Elizabeth;

YEAR: 2019     DOI: 10.1029/2019GL082789

aurora; kinetic Alfven wave; Plasmapause; STEVE; subauroral ion drift; table red auroral arc; Van Allen Probes

Global Occurrences of Auroral Kilometric Radiation Related to Suprathermal Electrons in Radiation Belts

Auroral kilometric radiation (AKR) can potentially produce serious damage to space-borne systems by accelerating trapped radiation belt electrons to relativistic energies. Here we examine the global occurrences of AKR emissions in radiation belts based on Van Allen Probes observations from 1 October 2012 to 31 December 2016. The statistical results (1,848 events in total) show that AKR covers a broad region of L= 3\textendash6.5 and 00\textendash24 magnetic local time (MLT), with a higher occurrence on the nightside (20\text ...

Zhao, Wanli; Liu, Si; Zhang, Sai; Zhou, Qinghua; Yang, Chang; He, Yihua; Gao, Zhonglei; Xiao, Fuliang;

YEAR: 2019     DOI: 10.1029/2019GL083944

Auroral kilometric radiation; global occurrence; Radiation belt; suprathermal electron flux enhancenments; Van Allen Probes

Characteristics of high energy proton responses to geomagnetic activities in the inner radiation belt observed by the RBSP satellite

High energy trapped particles in the radiation belts constitute potential threats to the functionality of satellites as they enter into those regions. In the inner radiation belt, the characteristics of high-energy (>20MeV) protons variations during geomagnetic activity times have been studied by implementing four-year (2013-2016) observations of the Van Allen probes. An empirical formula has been used to remove the satellite orbit effect, by which proton fluxes have been normalized to the geomagnetic equator. Case studies s ...

Xu, Jiyao; He, Zhaohai; Baker, D.N.; Roth, Ilan; Wang, C.; Kanekal, S.G.; Jaynes, A.N.; Liu, Xiao;

YEAR: 2019     DOI: 10.1029/2018JA026205

geomagnetic activities; high energy proton; Inner radiation belt; one-to-one correspondence; prompt responses; RBSP satellite; Van Allen Probes

Quenching of Equatorial Magnetosonic Waves by Substorm Proton Injections

Near equatorial (fast) magnetosonic waves, characterized by high magnetic compressibility, are whistler-mode emissions destabilized by proton shell/ring distributions. In the past, substorm proton injections are widely known to intensify magnetosonic waves in the inner magnetosphere. Here we report the unexpected observations by the Van Allen Probes of the magnetosonic wave quenching associated with the substorm proton injections under both high- and low-density conditions. The enhanced proton thermal pressure distorted the ...

Dai, Guyue; Su, Zhenpeng; Liu, Nigang; Wang, Bin; Zheng, Huinan; Wang, Yuming; Wang, Shui;

YEAR: 2019     DOI: 10.1029/2019GL082944

Bernstein mode instability; magnetosonic wave; Radiation belt; ring current; substorm injection; Van Allen Probes; Wave-particle interaction

Triggered Plasmaspheric Hiss: Rising Tone Structures

In this study, a rare hiss event observed by Van Allen Probe is reported and the possible generation is investigated based on wave and plasma measurements. The results suggest that the normal hiss (from 0.05fce to 0.5fce) with dominantly equatorward Poynting fluxes is locally generated by plasma sheet electrons via cyclotron instability. The low-frequency band (from 30 Hz to 0.05fce) with a mixture of equatorward and poleward Poynting fluxes is probably due to multiple reflections inside the plasmasphere. Such difference in ...

Zhu, Hui; Liu, Xu; Chen, Lunjin;

YEAR: 2019     DOI: 10.1029/2019GL082688

Plasmaspheric Hiss; Radiation belts; Rising tone structure; Van Allen Probes

Global occurrences of electrostatic electron cyclotron harmonic waves associated with radiation belt electron distributions

Electrostatic electron cyclotron harmonic (ECH) waves can yield diffuse aurora primarily at higher L-shells by driving efficient precipitation loss of plasma sheet electrons. Here using the Van Allen Probes high resolution data, we examine in detail the global occurrences of ECH waves during the period from October 1, 2012 to June 30, 2017 and find that there are totally 419 events of enhanced ECH waves. The statistical results demonstrate that ECH waves can be present over a broad region of L=4-6 and 00-24 MLT, with a highe ...

Chen, Yaru; Zhou, Qinghua; He, Yihua; Yang, Chang; Liu, Si; Gao, Zhonglei; Xiao, Fuliang;

YEAR: 2019     DOI: 10.1029/2019GL082668

electron ring distribution; global occurrences; Radiation belt; Van Allen Probe observation; Van Allen Probes; waves

Modulation of Locally Generated Equatorial Noise by ULF Wave

In this paper we report a rare and fortunate event of fast magnetosonic (MS, also called equatorial noise) waves modulated by compressional ultralow frequency (ULF) waves measured by Van Allen Probes. The characteristics of MS waves, ULF waves, proton distribution, and their potential correlations are analyzed. The results show that ULF waves can modulate the energetic ring proton distribution and in turn modulate the MS generation. Furthermore, the variation of MS intensities is attributed to not only ULF wave activities bu ...

Zhu, Hui; Chen, Lunjin; Liu, Xu; Shprits, Yuri;

YEAR: 2019     DOI: 10.1029/2018JA026199

linear growth rate; magnetosonic waves; Radiation belts; ULF waves; Van Allen Probes

Contribution of ULF wave activity to the global recovery of the outer radiation belt during the passage of a high-speed solar wind stream observed in September 2014

Energy coupling between the solar wind and the Earth\textquoterights magnetosphere can affect the electron population in the outer radiation belt. However, the precise role of different internal and external mechanisms that leads to changes of the relativistic electron population is not entirely known. This paper describes how Ultra Low Frequency (ULF) wave activity during the passage of Alfv\ enic solar wind streams contributes to the global recovery of the relativistic electron population in the outer radiation belt. To in ...

Da Silva, L.; Sibeck, D.; Alves, L.; Souza, V.; Jauer, P.; Claudepierre, S.; Marchezi, J.; Agapitov, O.; Medeiros, C.; Vieira, L.; Wang, C.; Jiankui, S.; Liu, Z.; Gonzalez, W.; Dal Lago, A.; Rockenbach, M.; Padua, M.; Alves, M.; Barbosa, M.; Fok, M.-C.; Baker, D.; Kletzing, C.; Kanekal, S.; Georgiou, M.;

YEAR: 2019     DOI: 10.1029/2018JA026184

alfv\ en fluctuations; Earth\textquoterights magnetosphere; high speed stream; Radiation belts; relativistic electron flux; ULF wave; Van Allen Probes

Local Generation of High-Frequency Plasmaspheric Hiss Observed by Van Allen Probes

The generation of a high-frequency plasmaspheric hiss (HFPH) wave observed by Van Allen Probes is studied in this letter for the first time. The wave has a moderate power spectral density (\~10-6 nT2/Hz), with a frequency range extended from 2 to 10 kHz. The correlated observations of waves and particles indicate that HFPH is associated with the enhancement of electron flux during the substorm on 6 January 2014. Calculations of the wave linear growth rate driven by the fitted electron phase space density show that the electr ...

He, Zhaoguo; Chen, Lunjin; Liu, Xu; Zhu, Hui; Liu, Si; Gao, Zhonglei; Cao, Yong;

YEAR: 2019     DOI: 10.1029/2018GL081578

electron; high frequency; local generation; Plasmaspheric Hiss; substorm injection; Van Allen Probes

Local Generation of High-Frequency Plasmaspheric Hiss Observed by Van Allen Probes

The generation of a high-frequency plasmaspheric hiss (HFPH) wave observed by Van Allen Probes is studied in this letter for the first time. The wave has a moderate power spectral density (\~10-6 nT2/Hz), with a frequency range extended from 2 to 10 kHz. The correlated observations of waves and particles indicate that HFPH is associated with the enhancement of electron flux during the substorm on 6 January 2014. Calculations of the wave linear growth rate driven by the fitted electron phase space density show that the electr ...

He, Zhaoguo; Chen, Lunjin; Liu, Xu; Zhu, Hui; Liu, Si; Gao, Zhonglei; Cao, Yong;

YEAR: 2019     DOI: 10.1029/2018GL081578

electron; high frequency; local generation; Plasmaspheric Hiss; substorm injection; Van Allen Probes

2018

Equatorial Evolution of the Fast Magnetosonic Mode in the Source Region: Observation-Simulation Comparison of the Preferential Propagation Direction

Recent analysis of an event observed by the Van Allen Probes in the source region outside the plasmapause has shown that fast magnetosonic waves (also referred to as equatorial noise) propagate preferentially in the azimuthal direction, implying that wave amplification should occur during azimuthal propagation. To demonstrate this, we carry out 2-D particle-in-cell simulations of the fast magnetosonic mode at the dipole magnetic equator with the simulation box size, the magnetic field inhomogeneity, and the plasma parameters ...

Min, Kyungguk; Boardsen, Scott; Denton, Richard; Liu, Kaijun;

YEAR: 2018     DOI: 10.1029/2018JA026037

2D particle-in-cell simulation; Fast Magnetosonic Waves; Perpendicular propagation; Van Allen Probes

Nonlinear coupling between whistler-mode chorus and electron cyclotron harmonic waves in the magnetosphere

Electromagnetic whistler-mode chorus and electrostatic electron cyclotron harmonic (ECH) waves can contribute significantly to auroral electron precipitation and radiation belt electron acceleration. In the past, linear and nonlinear wave-particle interactions have been proposed to explain the occurrences of these magnetospheric waves. By analyzing Van Allen Probes data, we present here the first evidence for nonlinear coupling between chorus and ECH waves. The sum-frequency and difference-frequency interactions produced the ...

Gao, Zhonglei; Su, Zhenpeng; Xiao, Fuliang; Summers, Danny; Liu, Nigang; Zheng, Huinan; Wang, Yuming; Wei, Fengsi; Wang, Shui;

YEAR: 2018     DOI: 10.1029/2018GL080635

aurora; Chorus wave; electron cyclotron harmonic wave; nonlinear wave-wave interaction; Radiation belt; Van Allen Probes

Precipitation of radiation belt electrons by EMIC waves with conjugated observations of NOAA and Van Allen satellites

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

Yuan, Zhigang; Liu, Kun; Yu, Xiongdong; Yao, Fei; Huang, Shiyong; Wang, Dedong; Ouyang, Zhihai;

YEAR: 2018     DOI: 10.1029/2018GL080481

Chorus; EMIC waves; Particle precipitation; Radiation belt; ring current; Van Allen Probes; Wave-particle interaction

An event on simultaneous amplification of exohiss and chorus waves associated with electron density enhancements

Whistler mode exohiss are the structureless hiss waves observed outside the plasmapause with featured equatorward Poynting flux. An event of the amplification of exohiss as well as chorus waves was recorded by Van Allen Probes during the recovery phase of a weak geomagnetic storm. Amplitudes of both types of the waves showed a significant increase at the regions of electron density enhancements. It is found that the electrons resonant with exohiss and chorus showed moderate pitch-angle anisotropies. The ratio of the number o ...

Zhu, Hui; Shprits, Yuri; Chen, Lunjin; Liu, Xu; Kellerman, Adam;

YEAR: 2018     DOI: 10.1029/2017JA025023

electromagnetic waves; Exohiss; linear theory; Radiation belts; Van Allen Probes

Generation of lower L -shell dayside chorus by energetic electrons from the plasmasheet

Currently, the generation mechanism for the lower L-shell dayside chorus has still remained an open question. Here, we report two storm events: 06-07 March 2016 and 20-21 January 2016, when Van Allen Probes observed enhanced dayside chorus with lower and higher wave normal angles (the angles between the wave vector and the geomagnetic field) in the region of L = 3.5-6.3 and MLT = 5.6-13.5. Hot and energetic (\~ 1-100 keV) electrons displayed enhancements in fluxes and anisotropy when they were injected from the plasmasheet a ...

He, Yihua; Xiao, Fuliang; Su, Zhenpeng; Zheng, Huinan; Yang, Chang; Liu, Si; Zhou, Qinghua;

YEAR: 2018     DOI: 10.1029/2017JA024889

Dayside chorus generation; Radiation belt; Van Allen Probes; Wave-particle interaction

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;

YEAR: 2018     DOI: 10.1029/2018GL079038

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

Magnetosonic harmonic falling and rising frequency emissions potentially generated by nonlinear wave-wave interactions in the Van Allen radiation belts

Magnetosonic waves play a potentially important role in the complex evolution of the radiation belt electrons. These waves typically appear as discrete emission lines along the proton gyrofrequency harmonics, consistent with the prediction of the local Bernstein mode instability of hot proton ring distributions. Magnetosonic waves are nearly dispersionless particularly at low harmonics and therefore have the roughly unchanged frequency-time structures during the propagation. On the basis of Van Allen Probes observations, we ...

Liu, Nigang; Su, Zhenpeng; Zheng, Huinan; Wang, Yuming; Wang, Shui;

YEAR: 2018     DOI: 10.1029/2018GL079232

Bernstein mode instability; magnetosonic wave; Radiation belt; ring current; rising/falling frequency; Van Allen Probes; wave propagation

Observations of impulsive electric fields induced by Interplanetary Shock

We investigate the characteristics of impulsive electric fields in Earth\textquoterights 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 pres ...

Zhang, Dianjun; Liu, Wenlong; Li, Xinlin; Sarris, Theodore; Xiao, Chao; Wygant, J.;

YEAR: 2018     DOI: 10.1029/2018GL078809

electric field; inner magnetosphere; interplanetary shock; particle accelaration; Van Allen Probes

Quantifying Extremely Rapid Flux Enhancements of Radiation Belt Relativistic Electrons Associated With Radial Diffusion

Previous studies have revealed a typical picture that seed electrons are transported inward under the drive of radial diffusion and then accelerated via chorus to relativistic energies. Here we show a potentially different process during the 2\textendash3 October 2013 storm when Van Allen Probes observed extremely rapid (by about 50 times in 2 h) flux enhancements of relativistic (1.8\textendash3.4 MeV) electrons but without distinct chorus at lower L-shells. Meanwhile, Time History of Events and Macroscale Interactions duri ...

Liu, Si; Yan, Qi; Yang, Chang; Zhou, Qinghua; He, Zhaoguo; He, Yihua; Gao, Zhonglei; Xiao, Fuliang;

YEAR: 2018     DOI: 10.1002/grl.v45.310.1002/2017GL076513

chorus-driven acceleration; radial diffusion; Radiation belt; THEMIS; 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 ...

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

YEAR: 2018     DOI: 10.1002/2018JA025185

earthward propagation; radial propagation speed; substorm injection; tailward propagation; upper-cutoff magnetic moment; 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 ...

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

YEAR: 2018     DOI: 10.1002/2018JA025185

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

Storm-time evolution of outer radiation belt relativistic electrons by a nearly continuous distribution of chorus

During the 13-14 November 2012 storm, Van Allen Probe A simultaneously observed a 10-h period of enhanced chorus (including quasi-parallel and oblique propagation components) and relativistic electron fluxes over a broad range of L = 3-6 and MLT=2 - 10 within a complete orbit cycle. By adopting a Gaussian fit to the observed wave spectra, we obtain the wave parameters and calculate the bounce-averaged diffusion coefficients. We solve the Fokker-Planck diffusion equation to simulate flux evolutions of relativistic (1.8-4.2 Me ...

Yang, Chang; Xiao, Fuliang; He, Yihua; Liu, Si; Zhou, Qinghua; Guo, Mingyue; Zhao, Wanli;

YEAR: 2018     DOI: 10.1002/2017GL075894

energetic electron; Geomagnetic storm; outer radiation belt; Van Allen Probes; Wave-particle interaction; whistler-mode chorus wave

The Effect of Hot Protons on Magnetosonic Waves Inside and Outside the Plasmapause: New Observations and Theoretic Results

Based on the wave and proton observations by Van Allen Probes A and B, we examined the effects of hot protons (0.01\textendash50 keV) on fast magnetosonic (MS) waves inside and outside the Earth\textquoterights plasmasphere. In the low-density plasma trough outside the plasmapause, the gyroresonance interactions between hot protons and MS waves not only cause the MS wave growth at some frequencies but also lead to the damping of MS waves at other frequencies, which depends on the proton phase space density gradient and the a ...

Liu, Bin; Li, Liuyuan; Yu, Jiang; Cao, Jinbin;

YEAR: 2018     DOI: 10.1002/2017JA024676

damping of magnetosonic waves; growth of magnetosonic waves; magnetosonic waves; magnetospheric hot protons; Van Allen Probes; wave-particle interactions

Fast Magnetosonic Waves Observed by Van Allen Probes: Testing Local Wave Excitation Mechanism

Linear Vlasov theory and particle-in-cell (PIC) simulations for electromagnetic fluctuations in a homogeneous, magnetized, and collisionless plasma are used to investigate a fast magnetosonic wave event observed by the Van Allen Probes. The fluctuating magnetic field observed exhibits a series of spectral peaks at harmonics of the proton cyclotron frequency Ωp and has a dominant compressional component, which can be classified as fast magnetosonic waves. Furthermore, the simultaneously observed proton phase space density ex ...

Min, Kyungguk; Liu, Kaijun; Wang, Xueyi; Chen, Lunjin; Denton, Richard;

YEAR: 2018     DOI: 10.1002/2017JA024867

Fast Magnetosonic Waves; inner magnetosphere; observation-simulation comparison; Van Allen Probes; wave excitation

Large-Amplitude Extremely Low Frequency Hiss Waves in Plasmaspheric Plumes

Su, Zhenpeng; Liu, Nigang; Zheng, Huinan; Wang, Yuming; Wang, Shui;

YEAR: 2018     DOI: 10.1002/2017GL076754

electron instability; ELF hiss; generation mechanism; pitch angle scattering; precipitation loss; Radiation belt; Van Allen Probes

One-Dimensional Full Wave Simulation of Equatorial Magnetosonic Wave Propagation in an Inhomogeneous Magnetosphere

The effect of the plasmapause on equatorially radially propagating fast magnetosonic (MS) waves in the Earth\textquoterights 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 i ...

Liu, Xu; Chen, Lunjin; Yang, Lixia; Xia, Zhiyang; Malaspina, David;

YEAR: 2018     DOI: 10.1002/2017JA024336

fine-scale density structure; finite difference time domain; magnetosonic wave; Plasmapause; Van Allen Probes

Prompt Disappearance and Emergence of Radiation Belt Magnetosonic Waves Induced by Solar Wind Dynamic Pressure Variations

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 magn ...

Liu, Nigang; Su, Zhenpeng; Zheng, Huinan; Wang, Yuming; Wang, Shui;

YEAR: 2018     DOI: 10.1002/2017GL076382

magnetosonic waves; Radiation belt; ring current; solar wind dynamic pressure; Van Allen Probes; Wave-particle interaction

2017

Shock-induced disappearance and subsequent recovery of plasmaspheric hiss: Coordinated observations of RBSP, THEMIS and POES satellites

Plasmaspheric hiss is an extremely low frequency whistler-mode emission contributing significantly to the loss of radiation belt electrons. There are two main competing mechanisms for the generation of plasmaspheric hiss: excitation by local instability in the outer plasmasphere and origination from chorus outside the plasmasphere. Here, on the basis of the analysis of an event of shock-induced disappearance and subsequent recovery of plasmaspheric hiss observed by RBSP, THEMIS and POES missions, we attempt to identify its d ...

Liu, Nigang; Su, Zhenpeng; Gao, Zhonglei; Reeves, G.; Zheng, Huinan; Wang, Yuming; Wang, Shui;

YEAR: 2017     DOI: 10.1002/2017JA024470

Chorus; interplanetary shock; Plasmaspheric Hiss; Radiation belt; substorm injection; Van Allen Probes; Wave-particle interaction

Butterfly distribution of Earth\textquoterights radiation belt relativistic electrons induced by dayside chorus

Previous theoretical studies have shown that dayside chorus can produce butterfly distribution of energetic electrons in the Earth\textquoterights radiation belts by preferentially accelerating medium pitch angle electrons, but this requires the further confirmation from high-resolution satellite observation. Here, we report correlated Van Allen Probes data on wave and particle during the 11\textendash13 April, 2014 geomagnetic storm. We find that a butterfly pitch angle distribution of relativistic electrons is formed aroun ...

Jin, YuYue; Yang, Chang; He, Yihua; Liu, Si; Zhou, Qinghua; Xiao, Fuliang;

YEAR: 2017     DOI: 10.1007/s11431-017-9067-y

butterfly distribution relativistic electrons radiation belts wave-particle interaction dayside chorus; Van Allen Probes

Direct observation of generation and propagation of magnetosonic waves following substorm injection

Magnetosonic whistler mode waves play an important role in the radiation belt electron dynamics. Previous theory has suggested that these waves are excited by the ring distributions of hot protons and can propagate radially and azimuthally over a broad spatial range. However, because of the challenging requirements on satellite locations and data-processing techniques, this theory was difficult to validate directly. Here we present some experimental tests of the theory on the basis of Van Allen Probes observations of magneto ...

Su, Zhenpeng; Wang, Geng; Liu, Nigang; Zheng, Huinan; Wang, Yuming; Wang, Shui;

YEAR: 2017     DOI: 10.1002/2017GL074362

Bernstein mode instability; magnetosonic waves; Radiation belt; rising tone; substorm injection; Van Allen Probes; Wave-particle interaction

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.; . Y. Fu, S; Spence, H.; Blake, J.; Reeves, G.;

YEAR: 2017     DOI: 10.1002/2017GL074006

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

On the Relationship Between Electron Flux Oscillations and ULF Wave-Driven Radial Transport

The objective of this study is to investigate the relationship between the levels of electron flux oscillations and radial diffusion for different Phase Space Density (PSD) gradients, through observation and particle tracing simulations under the effect of model Ultra Low Frequency (ULF) fluctuations. This investigation aims to demonstrate that electron flux oscillation is associated with and could be used as an indicator of ongoing radial diffusion. To this direction, flux oscillations are observed through the Van Allen Pro ...

Sarris, Theodore; Li, Xinlin; Temerin, Michael; Zhao, Hong; Califf, Sam; Liu, Wenlong; Ergun, Robert;

YEAR: 2017     DOI: 10.1002/2016JA023741

Flux Oscillations; MAGEis; EMFISIS; EFW; Phase space density; radial diffusion; Radiation belts; Van Allen Probes



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