Biblio

Found 2 results
Filters: Author is John Wygant  [Clear All Filters]
2017
Authors: Li Jinxing, Bortnik Jacob, Li Wen, Thorne Richard M., Ma Qianli, et al.
Title: Coherently modulated whistler mode waves simultaneously observed over unexpectedly large spatial scales
Abstract: Utilizing simultaneous twin Van Allen Probes observations of whistler mode waves at variable separations, we are able to distinguish the temporal variations from spatial variations, determine the coherence spatial scale, and suggest the possible mechanism of wave modulation. The two probes observed coherently modulated whistler mode waves simultaneously at an unexpectedly large distance up to ~4.3 RE over 3 h during a relatively quiet period. The modulation of 150–500 Hz plasmaspheric hiss was correlated with whistler mode waves measured outside the plasmasphere across 3 h in magnetic local time and 3 L shells, revealing that the modulation was temporal in nature. We suggest that the coherent modulation of whistler mode waves was associated with the coherent ULF waves measured ov. . .
Date: 02/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023706 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA023706/full
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Authors: Takahashi Kazue, Denton Richard E., Kurth William, Kletzing Craig, Wygant John, et al.
Title: Externally driven plasmaspheric ULF waves observed by the Van Allen Probes
Abstract: We analyze data acquired by the Van Allen Probes on 8 November 2012, during a period of extended low geomagnetic activity, to gain new insight into plasmaspheric ultralow frequency (ULF) waves. The waves exhibited strong spectral power in the 5–40 mHz band and included multiharmonic toroidal waves visible up to the eleventh harmonic, unprecedented in the plasmasphere. During this wave activity, the interplanetary magnetic field cone angle was small, suggesting that the waves were driven by broadband compressional ULF waves originating in the foreshock region. This source mechanism is supported by the tailward propagation of the compressional magnetic field perturbations at a phase velocity of a few hundred kilometers per second that is determined by the cross-phase analysis of data from . . .
Date: 01/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2014JA020373 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2014JA020373
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