Diffusive scattering of electrons by electron holes around injection fronts - INSU - Institut national des sciences de l'Univers Accéder directement au contenu
Article Dans Une Revue Journal of Geophysical Research Space Physics Année : 2017

Diffusive scattering of electrons by electron holes around injection fronts

Résumé

Van Allen Probes have detected nonlinear electrostatic spikes around injection fronts in the outer radiation belt. These spikes include electron holes (EH), double layers, and more complicated solitary waves. We show that EHs can efficiently scatter electrons due to their substantial transverse electric fields. Although the electron scattering driven by EHs is diffusive, it cannot be evaluated via the standard quasi-linear theory. We derive analytical formulas describing local electron scattering by a single EH and verify them via test particle simulations. We show that the most efficiently scattered are gyroresonant electrons (crossing EH on a time scale comparable to the local electron gyroperiod). We compute bounce-averaged diffusion coefficients and demonstrate their dependence on the EH spatial distribution (latitudinal extent and spatial filling factor) and individual EH parameters (amplitude of electrostatic potential, velocity, and spatial scales). We show that EHs can drive pitch angle scattering of ≲5 keV electrons at rates 10 −2 − 10 −4 s −1 and, hence, can contribute to electron losses and conjugated diffuse aurora brightenings. The momentum and pitch angle scattering rates can be comparable, so that EHs can also provide efficient electron heating. The scattering rates driven by EHs at L shells L ∼ 5–8 are comparable to those due to chorus waves and may exceed those due to electron cyclotron harmonics.
Fichier principal
Vignette du fichier
Vasko_et_al-2017-Journal_of_Geophysical_Research__Space_Physics.pdf (5.16 Mo) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte

Dates et versions

insu-01520861 , version 1 (11-05-2017)

Identifiants

Citer

I. Y. Vasko, O. V. Agapitov, F. S. Mozer, A. V. Artemyev, Vladimir Krasnoselskikh, et al.. Diffusive scattering of electrons by electron holes around injection fronts. Journal of Geophysical Research Space Physics, 2017, 122 (3), pp.3163-3182. ⟨10.1002/2016JA023337⟩. ⟨insu-01520861⟩
120 Consultations
130 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More