Biblio

Found 4 results
Filters: Author is Agapitov, O.V.  [Clear All Filters]
2015
Authors: Mourenas D., Artemyev A. V., and Agapitov O.V.
Title: Approximate analytical formulation of radial diffusion and whistler-induced losses from a pre-existing flux peak in the plasmasphere
Abstract: Modeling the spatio-temporal evolution of relativistic electron fluxes trapped in the Earth's radiation belts in the presence of radial diffusion coupled with wave-induced losses should address one important question: how deep can relativistic electrons penetrate into the inner magnetosphere? However, a full modelling requires extensive numerical simulations solving the comprehensive quasi-linear equations describing pitch-angle and radial diffusion of the electron distribution, making it rather difficult to perform parametric studies of the flux behavior. Here, we consider the particular situation where a localized flux peak (or storage ring) has been produced at low L < 4 during a period of strong disturbances, through a combination of chorus-induced energy diffusion (or direct injection. . .
Date: 08/2015 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2015JA021623 Available at: http://doi.wiley.com/10.1002/2015JA021623
More Details
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
More Details
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
More Details
2014
Authors: Mourenas D., Artemyev A. V., Agapitov O.V., Krasnoselskikh V., and Li W
Title: Approximate analytical solutions for the trapped electron distribution due to quasi-linear diffusion by whistler-mode waves
Abstract: The distribution of trapped energetic electrons inside the Earth's radiation belts is the focus of intense studies aiming at better describing the evolution of the space environment in the presence of various disturbances induced by the solar wind or by an enhanced lightning activity. Such studies are usually performed by means of comparisons with full numerical simulations solving the Fokker-Planck quasi-linear diffusion equation for the particle distribution function. Here, we present for the first time approximate but realistic analytical solutions for the electron distribution, which are shown to be in good agreement with exact numerical solutions in situations where resonant scattering of energetic electrons by whistler-mode hiss, lightning-generated or chorus waves, is the dominant p. . .
Date: 11/2014 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2014JA020443 Available at: http://doi.wiley.com/10.1002/2014JA020443
More Details