Found 9 entries in the Bibliography.
Showing entries from 1 through 9
| 2021 |
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Abstract This paper examines the rapid losses and acceleration of trapped relativistic and ultrarelativistic electron populations in the Van Allen radiation belt during the September 7-9, 2017, geomagnetic storm. By analyzing the dynamics of the last closed drift shell (LCDS) and the electron flux and phase space density (PSD), we show that the electron dropouts are consistent with magnetopause shadowing and outward radial diffusion to the compressed LCDS. During the recovery phase an in-bound pass of Van Allen Probe A shows ... Olifer, L.; Mann, I.; Ozeke, L.; Morley, S.; Louis, H.; YEAR: 2021 DOI: https://doi.org/10.1029/2020GL092351 Van Allen Probes; magnetopause shadowing; ULF wave radial diffusion; electron phase space density |
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Abstract Based on Van Allen Probes observations, in this study we perform a statistical analysis of the spectral intensities of plasmaspheric hiss at L-shells of 1.8 – 3.0 in the slot region. Our results show that slot region hiss power intensifies with a strong day-night asymmetry as the level of substorm activity or L-shell increases. Using the statistical spectral profiles of plasmaspheric hiss, we calculate the drift- and bounce-averaged electron pitch angle diffusion coefficients and subsequently obtain the resultant ... Zhu, Qi; Cao, Xing; Gu, Xudong; Ni, Binbin; Xiang, Zheng; Fu, Song; Summers, Danny; Hua, Man; Lou, Yuequn; Ma, Xin; Guo, YingJie; Guo, DeYu; Zhang, Wenxun; YEAR: 2021 DOI: https://doi.org/10.1029/2020JA029057 Plasmaspheric Hiss; Slot region; Electron loss timescales; Van Allen Probes |
| 2019 |
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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 |
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Electromagnetic ion cyclotron waves have long been recognized to play a crucial role in the dynamic loss of ring current protons. While the field-aligned propagation approximation of electromagnetic ion cyclotron waves was widely used to quantify the scattering loss of ring current protons, in this study, we find that the wave normal distribution strongly affects the pitch angle scattering efficiency of protons. Increase of peak normal angle or angular width can considerably reduce the scattering rates of <=10 keV protons. F ... Cao, Xing; Ni, Binbin; Summers, Danny; Shprits, Yuri; Gu, Xudong; Fu, Song; Lou, Yuequn; Zhang, Yang; Ma, Xin; Zhang, Wenxun; Huang, He; Yi, Juan; YEAR: 2019 DOI: 10.1029/2018GL081550 EMIC waves; Quasi-linear diffusion; Ring current protons; Van Allen Probes; wave-particle interactions |
| 2018 |
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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 |
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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 |
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We describe a lightweight, accurate nowcasting model for electron flux levels measured by the Van Allen probes. Largely motivated by Rigler et al. [2004], we turn to a time-varying linear filter of previous flux levels and Kp. We train and test this model on data gathered from the 2.10 MeV channel of the Relativistic Electron-Proton Telescope (REPT) sensor onboard the Van Allen probes. Dynamic linear models are a specific case of state space models, and can be made flexible enough to emulate the nonlinear behavior of particl ... Coleman, Tim; McCollough, James; Young, Shawn; Rigler, E.; YEAR: 2018 DOI: 10.1029/2017SW001788 |
| 2017 |
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Intelligent Sampling of Hazardous Particle Populations in Resource-Constrained Environments Sampling of anomaly-causing space environment drivers is necessary for both real-time operations and satellite design efforts, and optimizing measurement sampling helps minimize resource demands. Relating these measurements to spacecraft anomalies requires the ability to resolve spatial and temporal variability in the energetic charged particle hazard of interest. Here we describe a method for sampling particle fluxes informed by magnetospheric phenomenology so that, along a given trajectory, the variations from both tempora ... McCollough, J.; Quinn, J.; Starks, M.; Johnston, W.; YEAR: 2017 DOI: 10.1002/2017SW001629 data sampling; magnetospheric plasma; measurement; Solar Energetic Protons; trapped electrons; trapped protons; Van Allen Probes |
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An interesting form of \textquotedblleftzipper-like\textquotedblright magnetosonic waves consisting of two bands of interleaved periodic rising-tone spectra was newly observed by the Van Allen Probes, the Time History of Events and Macroscale Interactions during Substorms (THEMIS), and the Magnetospheric Multiscale (MMS) missions. The two discrete bands are distinct in frequency and intensity; however, they maintain the same periodicity which varies in space and time, suggesting that they possibly originate from one single s ... Li, J.; Bortnik, J.; Li, W.; Ma, Q.; Thorne, R.; Kletzing, C.; Kurth, W.; Hospodarsky, G.; Wygant, J.; Breneman, A.; Thaller, S.; Funsten, H.; Mitchell, D.; Manweiler, J.; Torbert, R.; Le Contel, O.; Ergun, R.; Lindqvist, P.-A.; Torkar, K.; Nakamura, R.; Andriopoulou, M.; Russell, C.; YEAR: 2017 DOI: 10.1002/2016JA023536 magnetosonic wave; Radiation belt; rising-tone; Van Allen Probes; zipper-like |
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