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Filters: Author is Mozer, F.S.  [Clear All Filters]
2015
Authors: Mozer F.S., Agapitov O.V., Artemyev A., Drake J.F., Krasnoselskikh V., et al.
Title: Time Domain Structures: what and where they are, what they do, and how they are made
Abstract: Time Domain Structures (TDS) (electrostatic or electromagnetic electron holes, solitary waves, double layers, etc.) are ≥1 msec pulses having significant parallel (to the background magnetic field) electric fields. They are abundant through space and occur in packets of hundreds in the outer Van Allen radiation belts where they produce magnetic-field-aligned electron pitch angle distributions at energies up to a hundred keV. TDS can provide the seed electrons that are later accelerated to relativistic energies by whistlers and they also produce field-aligned electrons that may be responsible for some types of auroras. These field-aligned electron distributions result from at least three processes. The first process is parallel acceleration by Landau trapping in the TDS parallel electric . . .
Date: 04/2015 Publisher: Geophysical Research Letters DOI: 10.1002/2015GL063946 Available at: http://doi.wiley.com/10.1002/2015GL063946
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Authors: Mourenas D., Artemyev A. V., Agapitov O. V., Krasnoselskikh V., and Mozer F.S.
Title: Very Oblique Whistler Generation By Low Energy Electron Streams
Abstract: Whistler-mode chorus waves are present throughout the Earth's outer radiation belt as well as at larger distances from our planet. While the generation mechanisms of parallel lower-band chorus waves and oblique upper-band chorus waves have been identified and checked in various instances, the statistically significant presence in recent satellite observations of very oblique lower-band chorus waves near the resonance cone angle remains to be explained. Here we discuss two possible generation mechanisms for such waves. The first one is based on Landau resonance with sporadic very low energy (<4 keV) electron beams either injected from the plasmasheet or produced in situ. The second one relies on cyclotron resonance with low energy electron streams, such that their velocity distribution poss. . .
Date: 04/2015 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2015JA021135 Available at: http://doi.wiley.com/10.1002/2015JA021135
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Authors: Artemyev A.V., Agapitov O.V., Mourenas D., Krasnoselskikh V.V., and Mozer F.S.
Title: Wave energy budget analysis in the Earth’s radiation belts uncovers a missing energy
Abstract: Whistler-mode emissions are important electromagnetic waves pervasive in the Earth’s magnetosphere, where they continuously remove or energize electrons trapped by the geomagnetic field, controlling radiation hazards to satellites and astronauts and the upper-atmosphere ionization or chemical composition. Here, we report an analysis of 10-year Cluster data, statistically evaluating the full wave energy budget in the Earth’s magnetosphere, revealing that a significant fraction of the energy corresponds to hitherto generally neglected very oblique waves. Such waves, with 10 times smaller magnetic power than parallel waves, typically have similar total energy. Moreover, they carry up to 80% of the wave energy involved in wave–particle resonant interactions. It implies that electron heat. . .
Date: 05/2015 Publisher: Nature Communications Pages: 8143 DOI: 10.1038/ncomms8143 Available at: http://www.nature.com/doifinder/10.1038/ncomms8143
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