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Found 6 entries in the Bibliography.
Showing entries from 1 through 6
2019 |
Statistical analysis on plasmatrough exohiss waves from the Van Allen Probes In this study using Van Allen Probe wave observations we investigate the statistical properties of exohiss waves, which are structureless whistler mode waves observed outside the plasmapause. The exohiss waves are identified based on the cold electron number density, frequency distribution, ellipticity, and wave normal angle. The statistical analysis on exohiss wave properties shows that exohiss waves prefer to occur over 3 Zhu, Hui; Gu, Wenyao; Chen, Lunjin; Published by: Journal of Geophysical Research: Space Physics Published on: 06/2019 YEAR: 2019   DOI: 10.1029/2018JA026359 |
2018 |
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 of electrons resonating with exohiss to total electron number presented in-phase correlation with density variations, which suggests that exohiss can be amplified due to electron density enhancement in terms of cyclotron instability. The calculation of linear growth rates further supports above conclusion. We suggest that exohiss waves have potential to become more significant due to the background plasma fluctuation. Zhu, Hui; Shprits, Yuri; Chen, Lunjin; Liu, Xu; Kellerman, Adam; Published by: Journal of Geophysical Research: Space Physics Published on: 10/2018 YEAR: 2018   DOI: 10.1029/2017JA025023 electromagnetic waves; Exohiss; linear theory; Radiation belts; Van Allen Probes |
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 waves are most intense, the electron butterfly distribution is inhibited by exohiss and chorus, and electrons are considerably accelerated by combined scattering of MS and chorus waves. The simulated electron pitch angle distributions exhibit the variation trend consistent with the observations. Our results strongly suggest that competition and cooperation between resonant interactions with concurrently occurring magnetospheric waves need to be carefully treated in modeling and comprehending the radiation belt electron dynamics. Hua, Man; Ni, Binbin; Fu, Song; Gu, Xudong; Xiang, Zheng; Cao, Xing; Zhang, Wenxun; He, Ying; Huang, He; Lou, Yuequn; Zhang, Yang; Published by: Geophysical Research Letters Published on: 09/2018 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 |
2017 |
Magnetospheric whistler mode waves are of great importance in the radiation belt electron dynamics. Here on the basis of the analysis of a rare event with the simultaneous disappearances of whistler mode plasmaspheric hiss, exohiss, and chorus triggered by a sudden decrease in the solar wind dynamic pressure, we provide evidences for the following physical scenarios: (1) nonlinear generation of chorus controlled by the geomagnetic field inhomogeneity, (2) origination of plasmaspheric hiss from chorus, and (3) leakage of plasmaspheric hiss into exohiss. Following the reduction of the solar wind dynamic pressure, the dayside geomagnetic field configuration with the enhanced inhomogeneity became unfavorable for the generation of chorus, and the quenching of chorus directly caused the disappearances of plasmaspheric hiss and then exohiss. Liu, Nigang; Su, Zhenpeng; Gao, Zhonglei; Zheng, Huinan; Wang, Yuming; Wang, Shui; Spence, H.; Reeves, G.; Baker, D.; Blake, J.; Funsten, H.; Wygant, J.; Published by: Geophysical Research Letters Published on: 01/2017 YEAR: 2017   DOI: 10.1002/2016GL071987 Chorus; Exohiss; Plasmaspheric Hiss; Van Allen Probes; wave disappearance; wave generation |
Magnetospheric whistler mode waves are of great importance in the radiation belt electron dynamics. Here on the basis of the analysis of a rare event with the simultaneous disappearances of whistler mode plasmaspheric hiss, exohiss, and chorus triggered by a sudden decrease in the solar wind dynamic pressure, we provide evidences for the following physical scenarios: (1) nonlinear generation of chorus controlled by the geomagnetic field inhomogeneity, (2) origination of plasmaspheric hiss from chorus, and (3) leakage of plasmaspheric hiss into exohiss. Following the reduction of the solar wind dynamic pressure, the dayside geomagnetic field configuration with the enhanced inhomogeneity became unfavorable for the generation of chorus, and the quenching of chorus directly caused the disappearances of plasmaspheric hiss and then exohiss.
Published by: Geophysical Research Letters Published on: 01/2017 YEAR: 2017   DOI: 10.1002/2016GL071987 Chorus; Exohiss; Plasmaspheric Hiss; Van Allen Probes; wave disappearance; wave generation |
2015 |
Exohiss waves are whistler mode hiss observed in the plasmatrough region. We present a case study of exohiss waves and the corresponding background plasma distributions observed by the Van Allen Probes in the dayside low-latitude region. The analysis of wave Poynting fluxes, suprathermal electron fluxes and cold electron densities supports the scenario that exohiss leaks from the plasmasphere into the plasmatrough. Quasilinear calculations further reveal that exohiss can potentially cause the resonant scattering loss of radiation belt electrons ~ Zhu, Hui; Su, Zhenpeng; Xiao, Fuliang; Zheng, Huinan; Wang, Yuming; Shen, Chao; Xian, Tao; Wang, Shui; Kletzing, C.; Kurth, W.; Hospodarsky, G.; Spence, H.; Reeves, G.; Funsten, H.; Blake, J.; Baker, D.; Published by: Geophysical Research Letters Published on: 02/2015 YEAR: 2015   DOI: 10.1002/2014GL062964 Cyclotron resonance; Exohiss; Landau damping; Plasmaspheric Hiss; Radiation belt electron loss; Van Allen Probes |
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