Found 11 entries in the Bibliography.

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How Sudden, Intense Energetic Electron Enhancements Correlate With the Innermost Plasmapause Locations Under Various Solar Wind Drivers and Geomagnetic Conditions

In this report, the relationship between innermost plasmapause locations (Lpp) and initial electron enhancements during both storm and nonstorm (Dst > -30 nT) periods are examined using data from the Van Allen Probes. The geomagnetic storms are classified into coronal mass ejection (CME)-driven and corotating interaction region (CIR)-driven storms to explore their influences on the initial electron enhancements, respectively. We also study nonstorm time electron enhancements and observe frequent, sudden (within two consecuti ...

Khoo, L.-Y.; Li, X.; Zhao, H.; Chu, X.; Xiang, Z.; Zhang, K.;

YEAR: 2019     DOI: 10.1029/2019JA027412

energetic electron enhancements; Plasmapause; Radiation Belt Dynamics; Van Allen Probes

Statistical Properties of Hiss in Plasmaspheric Plumes and Associated Scattering Losses of Radiation Belt Electrons

Whistler mode hiss acts as an important loss mechanism contributing to the radiation belt electron dynamics inside the plasmasphere and plasmaspheric plumes. Based on Van Allen Probes observations from September 2012 to December 2015, we conduct a detailed analysis of hiss properties in plasmaspheric plumes and illustrate that corresponding to the highest occurrence probability of plumes at L = 5.0\textendash6.0 and MLT = 18\textendash21, hiss emissions occur concurrently with a rate of >~80\%. Plume hiss can efficiently sca ...

Zhang, Wenxun; Ni, Binbin; Huang, He; Summers, Danny; Fu, Song; Xiang, Zheng; Gu, Xudong; Cao, Xing; Lou, Yuequn; Hua, Man;

YEAR: 2019     DOI: 10.1029/2018GL081863

Electron scattering; plasmaspheric plumes; plume hiss; Van Allen Probes


On the Initial Enhancement of Energetic Electrons and the Innermost Plasmapause Locations: CME-Driven Storm Periods

Using Van Allen Probes\textquoteright observations and established plasmapause location (Lpp) models, we investigate the relationship between the location of the initial enhancement (IE) of energetic electrons and the innermost (among all magnetic local time sectors) Lpp over five intense storm periods. Our study reveals that the IE events for 30 keV to 2MeV electrons always occurred outside of the innermost Lpp. On average, the inner extent of the IE events (LIE) for <800 keV electrons was closer to the innermost Lpp when c ...

Khoo, Leng; Li, Xinlin; Zhao, Hong; Sarris, Theodore; Xiang, Zheng; Zhang, Kun; Kellerman, Adam; Blake, Bernard;

YEAR: 2018     DOI: 10.1029/2018JA026074

energetic electron; enhancements; plasmasphere; Radiation belt; Van Allen Probes

Combined Scattering of Outer Radiation Belt Electrons by Simultaneously Occurring Chorus, Exohiss, and Magnetosonic Waves

We report a typical event that fast magnetosonic (MS) waves, exohiss, and two-band chorus waves occurred simultaneously on the dayside observed by Van Allen Probes on 25 December 2013. By combining calculations of electron diffusion coefficients and 2-D Fokker-Planck diffusion simulations, we quantitatively analyze the combined scattering effect of multiple waves to demonstrate that the net impact of combined scattering does not simply depend on the wave intensity dominance of various plasma waves. Although the observed MS w ...

Hua, Man; Ni, Binbin; Fu, Song; Gu, Xudong; Xiang, Zheng; Cao, Xing; Zhang, Wenxun; He, Ying; Huang, He; Lou, Yuequn; Zhang, Yang;

YEAR: 2018     DOI: 10.1029/2018GL079533

Combined scattering effect; diffusion simulations; Exohiss; magnetosonic waves; resonant wave-particle interactions; two-band chorus waves; Van Allen Probes

A Statistical Survey of Radiation Belt Dropouts Observed by Van Allen Probes

A statistical analysis on the radiation belt dropouts is performed based on 4 years of electron phase space density data from the Van Allen Probes. The μ, K, and L* dependence of dropouts and their driving mechanisms and geomagnetic and solar wind conditions are investigated using electron phase space density data sets for the first time. Our results suggest that electronmagnetic ion cyclotron (EMIC) wave scattering is the dominant dropout mechanism at low L* region, which requires the most active geomagnetic and solar wind ...

Xiang, Zheng; Tu, Weichao; Ni, Binbin; Henderson, M.; Cao, Xing;

YEAR: 2018     DOI: 10.1029/2018GL078907

EMIC wave; magnetopause shadowing; Phase space density; radial diffusion; radiation belt dropout; Van Allen Probes; wave particle interaction

Electron Scattering by Plasmaspheric Hiss in a Nightside Plume

Plasmaspheric hiss is known to play an important role in radiation belt electron dynamics in high plasma density regions. We present observations of two crossings of a plasmaspheric plume by the Van Allen Probes on 26 December 2012, which occurred unusually at the post-midnight-to-dawn sector between L ~ 4\textendash6 during a geomagnetically quiet period. This plume exhibited pronounced electron densities higher than those of the average plume level. Moderate hiss emissions accompanied the two plume crossings with the peak ...

Zhang, Wenxun; Fu, Song; Gu, Xudong; Ni, Binbin; Xiang, Zheng; Summers, Danny; Zou, Zhengyang; Cao, Xing; Lou, Yuequn; Hua, Man;

YEAR: 2018     DOI: 10.1029/2018GL077212

Electron scattering; nightside plumes; Plasmaspheric Hiss; Van Allen Probes

Resonant Scattering of Radiation Belt Electrons by Off-Equatorial Magnetosonic Waves

Fast magnetosonic (MS) waves are commonly regarded as electromagnetic waves that are characteristically confined within \textpm3\textdegree of the geomagnetic equator. We report two typical off-equatorial MS events observed by Van Allen Probes, that is, the 8 May 2014 event that occurred at the geomagnetic latitudes of 7.5\textdegree\textendash9.2\textdegree both inside and outside the plasmasphere with the wave amplitude up to 590 pT and the 9 January 2014 event that occurred at the latitudes of\textemdash(15.7\textdegree\t ...

Ni, Binbin; Zou, Zhengyang; Fu, Song; Cao, Xing; Gu, Xudong; Xiang, Zheng;

YEAR: 2018     DOI: 10.1002/grl.v45.310.1002/2017GL075788

butterfly pitch angle distributions; off-equatorial MS waves; radiation belt electrons; Van Allen Probes


Understanding the Mechanisms of Radiation Belt Dropouts Observed by Van Allen Probes

To achieve a better understanding of the dominant loss mechanisms for the rapid dropouts of radiation belt electrons, three distinct radiation belt dropout events observed by Van Allen Probes are comprehensively investigated. For each event, observations of the pitch angle distribution of electron fluxes and electromagnetic ion cyclotron (EMIC) waves are analyzed to determine the effects of atmospheric precipitation loss due to pitch angle scattering induced by EMIC waves. Last closed drift shells (LCDS) and magnetopause sta ...

Xiang, Zheng; Tu, Weichao; Li, Xinlin; Ni, Binbin; Morley, S.; Baker, D.;

YEAR: 2017     DOI: 10.1002/2017JA024487

EMIC wave; last closed drift shell; magnetopause shadowing; Phase space density; radiation belt dropout; Van Allen Probes

Variations of the relativistic electron flux after a magnetospheric compression event

On January 21, 2015, a sharp increase of the solar wind dynamic pressure impacted the magnetosphere. The magnetopause moved inward to the region L< 8 without causing a geomagnetic storm. The flux of the relativistic electrons in the outer radiation belt decreased by half during this event based on the observations of the particle radiation monitor (PRM) of the fourth of the China-Brazil Earth Resource Satellites (CBERS-4). The flux remained low for approximately 11 d; it did not recover after a small magnetic storm on Januar ...

Chen, Zhe; Chen, HongFei; Li, YiFan; Xiang, HongWen; Yu, XiangQian; Shi, WeiHong; Hao, ZhiHua; Zou, Hong; Zou, JiQing; Zhong, WeiYing;

YEAR: 2017     DOI: 10.1007/s11431-016-9008-3

outer radiation belt high-energy electrons medium-energy electrons space environment; Van Allen Probes

Inferring electromagnetic ion cyclotron wave intensity from low altitude POES proton flux measurements: A detailed case study with conjugate Van Allen Probes observations

Zhang, Yang; Shi, Run; Ni, Binbin; Gu, Xudong; Zhang, Xianguo; Zuo, Pingbing; Fu, Song; Xiang, Zheng; Wang, Qi; Cao, Xing; Zou, Zhengyang;

YEAR: 2017     DOI: 10.1016/j.asr.2016.12.035

Van Allen Probes


Combined Scattering Loss of Radiation Belt Relativistic Electrons by Simultaneous Three-band EMIC Waves: A Case Study

Multiband electromagnetic ion cyclotron (EMIC) waves can drive efficient scattering loss of radiation belt relativistic electrons. However, it is statistically uncommon to capture the three bands of EMIC waves concurrently. Utilizing data from the Electric and Magnetic Field Instrument Suite and Integrated Science magnetometer onboard Van Allen Probe A, we report the simultaneous presence of three (H+, He+, and O+) emission bands in an EMIC wave event, which provides an opportunity to look into the combined scattering effect ...

He, Fengming; Cao, Xing; Ni, Binbin; Xiang, Zheng; Zhou, Chen; Gu, Xudong; Zhao, Zhengyu; Shi, Run; Wang, Qi;

YEAR: 2016     DOI: 10.1002/2016JA022483

combined scattering rates; electromagnetic ion cyclotron waves; loss timescales; radiation belt relativistic electrons; resonant wave-particle interactions; Van Allen Probes