Van Allen Probes Bibliography is from August 2012 through September 2021 Notice:
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Bounce resonance scattering of radiation belt electrons by low-frequency hiss: Comparison with cyclotron and Landau resonances
Author | Cao, Xing; Ni, Binbin; Summers, Danny; Zou, Zhengyang; Fu, Song; Zhang, Wenxun; |
Keywords | bounce resonance; Low-frequency hiss; Radiation Belt Dynamics; Van Allen Probes; wave-particle interactions |
Abstract | Bounce-resonant interactions with magnetospheric waves have been proposed as important contributing mechanisms for scattering near-equatorially mirroring electrons by violating the second adiabatic invariant associated with the electron bounce motion along a geomagnetic field line. This study demonstrates that low-frequency plasmaspheric hiss with significant wave power below 100 Hz can bounce-resonate efficiently with radiation belt electrons. By performing quantitative calculations of pitch-angle scattering rates, we show that low-frequency hiss induced bounce-resonant scattering of electrons has a strong dependence on equatorial pitch-angle αeq. For electrons with αeq close to 90\textdegree, the timescale associated with bounce resonance scattering can be comparable to or even less than 1 hour. Cyclotron- and Landau-resonant interactions between low-frequency hiss and electrons are also investigated for comparisons. It is found that while the bounce and Landau resonances are responsible for the diffusive transport of near-equatorially mirroring electrons to lower αeq, pitch-angle scattering by cyclotron resonance could take over to further diffuse electrons into the atmosphere. Bounce resonance provides a more efficient pitch-angle scattering mechanism of relativistic (>= 1 MeV) electrons than Landau resonance due to the stronger scattering rates and broader resonance coverage of αeq, thereby demonstrating that bounce resonance scattering by low-frequency hiss can contribute importantly to the evolution of the electron pitch-angle distribution and the loss of radiation belt electrons. |
Year of Publication | 2017 |
Journal | Geophysical Research Letters |
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Number of Pages | |
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Date Published | 09/2017 |
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URL | http://onlinelibrary.wiley.com/doi/10.1002/2017GL075104/full |
DOI | 10.1002/2017GL075104 |