Bibliography





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Found 26 entries in the Bibliography.


Showing entries from 1 through 26


2021

Electromagnetic characteristics of fast magnetosonic waves in the inner magnetosphere

Abstract In evaluating the effects of fast magnetosonic (MS) waves on magnetospheric particles, their magnetic spectra are often obtained from satellite observations, while electric field components are usually derived under the cold plasma approximation. However, such an approximation has not been verified with in situ observations yet. In this paper, we report the electromagnetic characteristic for MS waves in various plasma environments with observations of the Van Allen Probe A. It is found that a considerable number of ...

Yu, Xiongdong; Yuan, Zhigang; Yao, Fei; Ouyang, Zhihai; Wang, Dedong;

Published by: Journal of Geophysical Research: Space Physics      Published on: 08/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021JA029759

Fast Magnetosonic Waves; Electromagnetic characteristics; Van Allen Probes; Cold plasma approximation

Formation of the mass density peak at the magnetospheric equator triggered by EMIC waves

Abstract We report a simultaneous observation of two band electromagnetic ion cyclotron (EMIC) waves and toroidal Alfvén waves by the Van Allen Probe mission. Through wave frequency analyses, the mass density ρ is found to be locally peaked at the magnetic equator. Perpendicular fluxes of ions (< 100 eV) increase simultaneously with the appearances of EMIC waves, indicating a heating of these ions by EMIC waves. In addition, the measured ion distributions also support the equatorial peak formation, which accords with the r ...

Xue, Zuxiang; Yuan, Zhigang; Yu, Xiongdong; Shiyong, Huang; Qiao, Zheng;

Published by: Earth and Planetary Physics      Published on: 03/2021

YEAR: 2021     DOI: https://doi.org/10.26464/epp2021008

Toroidal Alfven waves; EMIC waves; magnetoseismology; equatorial mass density peak; Van Allen Probes

Effects of the plasmapause on the radial propagation of fast magnetosonic waves: An Analytical Approach

Abstract In this paper, analytical approximation is used to solve the wave equations near the plasmapause boundary layer in order to examine the validity of ray tracing approach for fast magnetosonic (MS) wave propagations, and then analytical solutions for electromagnetic fields of MS waves through the plasmapause boundary layer are provided for the first time. Both theoretical calculations from the analytical expressions and observations of Van Allen Probes have indicated that electric fields of MS waves decrease rapidly b ...

Yu, Xiongdong; Yuan, Zhigang; Ouyang, Zhihai; Yao, Fei;

Published by: Journal of Geophysical Research: Space Physics      Published on: 02/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2020JA028330

MS waves; Radial propagation; Analytical approach; WKB approximation; Van Allen Probes

2020

Prompt emergence and disappearance of EMIC waves driven by the sequentially enhanced solar wind dynamic pressure

Van Allen Probes (VAPs) and multiple ground-based stations simultaneously observed prompt emergences and disappearances of electromagnetic ion cyclotron (EMIC) waves driven by the sequentially enhanced solar wind dynamic pressure in the dayside inner magnetosphere on 6 November 2015. The measured hot protons (> 60 keV) display enhancements of perpendicular temperature during compressions, which provides sufficient temperature anisotropies for the EMIC wave generation so that the calculated linear growth rate also agrees well ...

Xue, Zuxiang; Yuan, Zhigang; Yu, Xiongdong;

Published by: Geophysical Research Letters      Published on: 12/2020

YEAR: 2020     DOI: https://doi.org/10.1029/2020GL091479

EMIC wave; solar wind dynamic pressure; Magnetospheric compression; Multipoint observations; Van Allen Probes

Narrowband Magnetosonic Waves Near the Lower Hybrid Resonance Frequency in the Inner Magnetosphere: Wave Properties and Excitation Conditions

In this study, the excitation of narrowband fast magnetosonic (MS) waves near the lower hybrid resonance frequency (fLHR) has been investigated with observations from Van Allen Probes mission and linear growth theory. A typical wave event is first examined to show that these waves can be excited through linear instabilities driven by partial shell distributions of protons. Then it is found that these narrowband MS waves from 188 wave events observed by the Van Allen Probe A between January 1, 2013 to December 31, 2015 have c ...

Ouyang, Zhihai; Yuan, Zhigang; Yu, Xiongdong; Yao, Fei;

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

YEAR: 2020     DOI: https://doi.org/10.1029/2020JA028158

central frequencies; linear growth rates; lower hybrid resonance frequency; narrowband fast magnetosonic wave; Proton rings; Van Allen Probes

Analytical Fast Magnetosonic Wave Model Based on Observations of Van Allen Probe

Based on observations of Van Allen Probe-A during the period from 19 September 2012 to 28 February 2016, the relations of the fast magnetosonic (MS) wave amplitude Bw with kp index, the wave normal angle (WNA), and the wave normalized frequency (norF) are presented. Then, we establish an analytical regression model for MS wave amplitude as a function of geomagnetic storm activity (presented by kp index), L-shell (L), magnetic local time (MLT), magnetic latitude (λ), and the characteristics of MS wave, that is, wave norF and ...

Yao, Fei; Yuan, Zhigang; Yu, Xiongdong; Wang, Dedong; Ouyang, Zhihai;

Published by: Journal of Geophysical Research: Space Physics      Published on: 10/2020

YEAR: 2020     DOI: https://doi.org/10.1029/2020JA028527

fast magnetosonic wave; Van Allen Probe; analytical regression model; wave normal angle; Plasmapause; Van Allen Probes

Ionospheric Signatures of Ring Current Ions Scattered by Magnetosonic Waves

In this letter, we present unique conjugated satellite observations of ionospheric signatures of ring current (RC) ions scattered by fast magnetosonic (MS) waves. In the plasmasphere, the Van Allen Probe in situ observed MS waves. At ionospheric altitudes, the NOAA 16 satellite at the footprint of Van Allen Probe simultaneously observed obvious enhancements of mirroring RC ions, but no obvious variations of precipitating RC ions at subauroral latitudes. Theoretical calculations of pitch angle diffusion coefficients for RC io ...

Yuan, Zhigang; Yao, Fei; Yu, Xiongdong; Ouyang, Zhihai; Huang, Shiyong;

Published by: Geophysical Research Letters      Published on: 08/2020

YEAR: 2020     DOI: https://doi.org/10.1029/2020GL089032

magnetosonic waves; mirroring ions; pitch angle scatter; precipitating ions; Van Allen Probes; Ring current ions

Evolutions of equatorial ring current ions during a magnetic storm

In this paper, we present evolutions of the phase space density (PSD) spectra of ring current (RC) ions based on observations made by Van Allen Probe B during a geomagnetic storm on 23–24 August 2016. By analyzing PSD spectra ratios from the initial phase to the main phase of the storm, we find that during the main phase, RC ions with low magnetic moment μ values can penetrate deeper into the magnetosphere than can those with high μ values, and that the μ range of PSD enhancement meets the relationship: S(O+) > S(He+) > ...

Huang, Zheng; Yuan, Zhigang; Yu, Xiongdong;

Published by: Earth and Planetary Physics      Published on: 03/2020

YEAR: 2020     DOI: 10.26464/epp2020019

ULF waves; ring current; wave-particle interactions; Radial Transport; Geomagnetic storm; Decay rates; Van Allen Probes

2019

An Automatic Detection Algorithm Applied to Fast Magnetosonic Waves With Observations of the Van Allen Probes

Fast magnetosonic (MS) waves can play an important role in the evolution of the inner magnetosphere. However, there is still not an effective method to quantitatively identify such waves for observations of the Van Allen Probes reasonably. In this paper, we used Van Allen Probes data from 18 September 2012 to 30 September 2014 to find a more comprehensive automatic detection algorithm for fast MS waves through statistical analysis of the major properties, including the planarity, ellipticity, and wave normal angle of whole f ...

Yuan, Zhigang; Yao, Fei; Yu, Xiongdong; Huang, Shiyong; Ouyang, Zhihai;

Published by: Journal of Geophysical Research: Space Physics      Published on: Apr-05-2021

YEAR: 2019     DOI: 10.1029/2018JA026387

ellipticity; magnetosonic wave; normalized distribution; planarity; Van Allen Probes; wave normal angle

Saturation Characteristics of Parallel EMIC Waves in the Inner Magnetosphere

In this letter, detailed evolution process of parallel electromagnetic ion cyclotron waves in the inner magnetosphere has been investigated through quasilinear theory. A new saturation has been found to occur after the usual first saturation. During the interval between these two saturations, the energy transfers from H+ band to He+ band electromagnetic ion cyclotron waves. Moreover, through a best fitting, we obtain new model parameters for the anisotropy-beta inverse relation of hot H+, which identifies the threshold of io ...

Yu, Xiongdong; Yuan, Zhigang;

Published by: Geophysical Research Letters      Published on: 07/2019

YEAR: 2019     DOI: 10.1029/2019GL083630

Anisotropy-beta inverse relation; EMIC waves; Quasilinear theory; RC ions; Van Allen Probes

Excitation of extremely low-frequency chorus emissions: The role of background plasma density

Low-frequency chorus emissions have recently attracted much attention due to the suggestion that they may play important roles in the dynamics of the Van Allen Belts. However, the mechanism (s) generating these low-frequency chorus emissions have not been well understood. . In this letter, we report an interesting case in which background plasma density lowered the lower cutoff frequency of chorus emissions from above 0.1 f ce (typical ordinary chorus) to 0.02 f ce (extremely low-frequency chorus). Those extremely low-freque ...

Yu, Xiongdong; Yuan, Zhigang; Huang, Shiyong; Yao, Fei; Qiao, Zheng; Wygant, John; Funsten, Herbert;

Published by: Earth and Planetary Physics      Published on: 02/2019

YEAR: 2019     DOI: 10.26464/epp2019001

anisotropic temperature instability; linear growth rate; low-frequency chorus emissions; Van Allen Probes; whistler mode

Simultaneous trapping of EMIC and MS waves by background plasmas

Electromagnetic ion cyclotron waves and fast magnetosonic waves are found to be simultaneously modulated by background plasma density: both kinds of waves were observed in high plasma density regions but vanished in low density regions. Theoretical analysis based on Snell\textquoterights law and linear growth theory have been utilized to investigate the physical mechanisms driving such modulation. It is suggested that the modulation of fast magnetosonic waves might be due to trapping by plasma density structures, which resul ...

Yuan, Zhigang; Yu, Xiongdong; Ouyang, Zhihai; Yao, Fei; Huang, Shiyong; Funsten, H.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 02/2019

YEAR: 2019     DOI: 10.1029/2018JA026149

EMIC waves; MS waves; Ring current ions; Van Allen Probes; Wave trapping

2018

Response of banded whistler-mode waves to the enhancement of solar wind dynamic pressure in the inner Earth\textquoterights magnetosphere

With observations of Van Allen Probe A, in this letter we display a typical event where banded whistler waves shifted up their frequencies with frequency bands broadening as a response to the enhancement of solar wind dynamic pressure. Meanwhile, the anisotropy of electrons with energies about several tens of keV was observed to increase. Through the comparison of the calculated wave growth rates and observed wave spectral intensity, we suggest that those banded whistler waves observed with frequencies shifted up and frequen ...

Yu, Xiongdong; Yuan, Zhigang; Li, Haimeng; Huang, Shiyong; Wang, Dedong; Yao, Fei; Funsten, H.; Wygant, J.;

Published by: Geophysical Research Letters      Published on: Mar-08-2020

YEAR: 2018     DOI: 10.1029/2018GL078849

Banded whistler-mode waves; Frequency properties; inner magnetosphere; solar wind dynamic pressure; 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;

Published by: Geophysical Research Letters      Published on: 11/2018

YEAR: 2018     DOI: 10.1029/2018GL080481

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

Global distribution of proton rings and associated magnetosonic wave instability in the inner magnetosphere

Using the Van Allen Probe A observations, we obtained the global distribution of proton rings and calculated the linear wave growth rate of fast magnetosonic (MS) waves in the region L ~ 3-6. Our statistical and calculated results demonstrate that MS waves can be locally excited on the dayside outside the plasmapause, as well as in the dusk sector inside the plasmapause. The frequency range of unstable MS waves is strongly modulated by the ratio of the proton ring velocity (Vr) to the local Alfv\ en speed (VA). High harmonic ...

Yuan, Zhigang; Ouyang, Zhihai; Yu, Xiongdong; Huang, Shiyong; Yao, Fei; Funsten, H.;

Published by: Geophysical Research Letters      Published on: 09/2018

YEAR: 2018     DOI: 10.1029/2018GL079999

Fast Magnetosonic Waves; linear growth rates; locally excited; low harmonic magnetosonic waves; Proton rings; Van Allen Probes

Cold Ion Heating by Magnetosonic Waves in a Density Cavity of the Plasmasphere

Fast magnetosonic (MS) waves play an important role in the dynamics of the inner magnetosphere. Theoretical prediction and simulation have demonstrated that MS waves can heat cold ions. However, direct observational evidence of cold ion heating by MS waves has so far remained elusive. In this paper, we show a typical event of cold ion heating by magnetosonic waves in a density cavity of the plasmasphere with observations of the Van Allen Probe mission on 22 August 2013. During enhancements of the MS wave intensity in the den ...

Yuan, Zhigang; Yu, Xiongdong; Huang, Shiyong; Qiao, Zheng; Yao, Fei; Funsten, Herbert;

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

YEAR: 2018     DOI: 10.1002/2017JA024919

cold ion heating; Density cavities; local linear growth rates; magnetosonic waves; Ring current ions; Van Allen Probes; \textquoteleftring\textquoteright distributions

Excitation of O + Band EMIC Waves Through H + Ring Velocity Distributions: Van Allen Probe Observations

A typical case of electromagnetic ion cyclotron (EMIC) emissions with both He+ band and O+ band waves was observed by Van Allen Probe A on 14 July 2014. These emissions occurred in the morning sector on the equator inside the plasmasphere, in which region O+ band EMIC waves prefer to appear. Through property analysis of these emissions, it is found that the He+ band EMIC waves are linearly polarized and propagating quasi-parallelly along the background magnetic field, while the O+ band ones are of linear and left-hand polari ...

Yu, Xiongdong; Yuan, Zhigang; Huang, Shiyong; Yao, Fei; Wang, Dedong; Funsten, Herbert; Wygant, John;

Published by: Geophysical Research Letters      Published on: 02/2018

YEAR: 2018     DOI: 10.1002/grl.v45.310.1002/2018GL077109

linear wave growth; O+ band EMIC waves; ring distributions; Van Allen Probes

2017

EMIC waves covering wide L shells: MMS and Van Allen Probes observations

During 04:45:00\textendash08:15:00 UT on 13 September in 2015, a case of Electromagnetic ion cyclotron (EMIC) waves covering wide L shells (L = 3.6\textendash9.4), observed by the Magnotospheric Multiscale 1 (MMS1) are reported. During the same time interval, EMIC waves observed by Van Allen Probes A (VAP-A) only occurred just outside the plasmapause. As the Van Allen Probes moved outside into a more tenuous plasma region, no intense waves were observed. Combined observations of MMS1 and VAP-A suggest that in the terrestrial ...

Yu, Xiongdong; Yuan, Zhigang; Huang, Shiyong; Wang, Dedong; Li, Haimeng; Qiao, Zheng; Yao, Fei;

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

YEAR: 2017     DOI: 10.1002/2017JA023982

EMIC waves; MMS; solar wind dynamic pressure; Van Allen Probes

In situ observations of magnetosonic waves modulated by background plasma density

We report in situ observations by the Van Allen Probe mission that magnetosonic (MS) waves are clearly relevant to appear relevant to the background plasma number density. As the satellite moved across dense and tenuous plasma alternatively, MS waves occurred only in lower density region. As the observed protons with \textquoteleftring\textquoteright distributions provide free energy, local linear growth rates are calculated and show that magnetosonic waves can be locally excited in tenuous plasma. With variations of the bac ...

Yuan, Zhigang; Yu, Xiongdong; Huang, Shiyong; Wang, Dedong; Funsten, Herbert;

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

YEAR: 2017     DOI: 10.1002/2017GL074681

\textquoterightring\textquoteright distributions; local linear growth rates; magnetosonic waves; Ring current ions; Van Allen Probes

2016

In situ evidence of the modification of the parallel propagation of EMIC waves by heated He + ions

With observations of the Van Allen Probe B, we report in situ evidence of the modification of the parallel propagating electromagnetic ion cyclotron (EMIC) waves by heated He+ ions. In the outer boundary of the plasmasphere, accompanied with the He+ ion heating, the frequency bands of H+ and He+ for EMIC waves merged into each other, leading to the disappearance of a usual stop band between the gyrofrequency of He+ ions (ΩHe+) and the H+ cutoff frequency (ωH+co) in the cold plasma. Moreover, the dispersion relation for EMI ...

Yuan, Zhigang; Yu, Xiongdong; Wang, Dedong; Huang, Shiyong; Li, Haimeng; Yu, Tao; Qiao, Zheng; Wygant, John; Funsten, Herbert;

Published by: Journal of Geophysical Research: Space Physics      Published on: 07/2016

YEAR: 2016     DOI: 10.1002/2016JA022573

EMIC waves; He+ ion heating; Ring current ions; stop band; 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.; . Y. 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.; . Y. 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

2015

Multiple loss processes of relativistic electrons outside the heart of outer radiation belt during a storm sudden commencement

By examining the compression-induced changes in the electron phase space density and pitch angle distribution observed by two satellites of Van Allen Probes (RBSP-A/B), we find that the relativistic electrons (>2MeV) outside the heart of outer radiation belt (L*>= 5) undergo multiple losses during a storm sudden commencement (SSC). The relativistic electron loss mainly occurs in the field-aligned direction (pitch angle α< 30\textdegree or >150\textdegree), and the flux decay of the field-aligned electrons is independent of ...

Yu, J.; Li, L.Y.; Cao, J.; Yuan, Z.; Reeves, G.; Baker, D.; Blake, J.; Spence, H.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 11/2015

YEAR: 2015     DOI: 10.1002/2015JA021460

Electromagnetic ion cyclotron (EMIC) waves; outer radiation belt; Outward radial diffusion driven by ULF waves; Plasmaspheric Hiss; relativistic electron loss; Storm sudden commencement; Van Allen Probes

The enhancement of cosmic radio noise absorption due to hiss-driven energetic electron precipitation during substorms

The Van-Allen probes, low-altitude NOAA satellite, MetOp satellite and riometer are used to analyze variations of precipitating energetic electron fluxes and cosmic radio noise absorption (CNA) driven by plasmaspheric hiss with respect to geomagnetic activities. The hiss-driven energetic electron precipitations (at L~4.7-5.3, MLT~8-9) are observed during geomagnetic quiet condition and substorms, respectively. We find that the CNA detected by riometers increased very little in the hiss-driven event during quiet condition on ...

Li, Haimeng; Yuan, Zhigang; Yu, Xiongdong; Huang, Shiyong; Wang, Dedong; Wang, Zhenzhen; Qiao, Zheng; Wygant, John;

Published by: Journal of Geophysical Research: Space Physics      Published on: 06/2015

YEAR: 2015     DOI: 10.1002/2015JA021113

cosmic radio noise absorption; energetic electron precipitation; hiss; substorm; Van Allen Probes

Statistical characteristic of EMIC waves: Van Allen Probe observations

Utilizing the data from the magnetometer instrument which is a part of the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) instrument suite onboard the Van Allen Probe A from Sep. 2012 to Apr. 2014, when the apogee of the satellite has passed all the MLT sectors, we obtain the statistical distribution characteristic of EMIC waves in the inner magnetosphere over all local times from L=3 to L=6. Compared with the previous statistical results about EMIC waves, the occurrence rates of EMIC waves dis ...

Wang, Dedong; Yuan, Zhigang; Yu, Xiongdong; Deng, Xiaohua; Zhou, Meng; Huang, Shiyong; Li, Haimeng; Wang, Zhenzhen; Qiao, Zheng; Kletzing, C.; Wygant, J.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 05/2015

YEAR: 2015     DOI: 10.1002/2015JA021089

distribution; EMIC waves; plasmasphere; Van Allen Probes

In situ observations of EMIC waves in O + band by the Van Allen Probe A

Through polarization and spectra analysis of the magnetic field observed by the Van Allen Probe A, we present two typical cases of O+ band EMIC waves in the outer plasmasphere or plasma trough. Although such O+ band EMIC waves are rarely observed, 18 different events of O+ band EMIC waves (16 events in the outer plasmasphere and 2 events in the plasma trough) are found from September 2012 to August 2014 with observations of the Van Allen Probe A. We find that the preferred region for the occurrence of O+ band EMIC waves is i ...

Yu, Xiongdong; Yuan, Zhigang; Wang, Dedong; Li, Haimeng; Huang, Shiyong; Wang, Zhenzhen; Zheng, Qiao; Zhou, Mingxia; Kletzing, C.; Wygant, J.;

Published by: Geophysical Research Letters      Published on: 02/2015

YEAR: 2015     DOI: 10.1002/2015GL063250

EMIC waves; O+ ion torus; oxygen band; Van Allen Probes



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