Approximate analytical solutions for the trapped electron distribution due to quasi‐linear diffusion by whistler mode waves. Issue 12 (18th December 2014)

• Record Type: Journal Article
• Authors: Mourenas, D.; Artemyev, A. V.; Agapitov, O. V.; Krasnoselskikh, V.; Li, W.
• Is Part Of: Journal of geophysical research. Volume 119:Issue 12(2014:Dec.)
• Page Start: 9962
• Page End: 9977
• Publication Date: 2014-12-18
• Subjects: electron distribution -- pitch‐angle distribution -- radiation belt; Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1002/2014JA020443
• Languages: English
• ISSNs: 2169-9380

Abstract

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 process. Quiet time distributions are well recovered, as well as the evolution of energized relativistic electron distributions during disturbed geomagnetic conditions. It is further shown that careful comparisons between the analytical solutions and measured distributions may allow to infer important bounce‐ and drift‐averaged wave characteristics (such as wave amplitude). It could also help to improve the global understanding of underlying physical phenomena. Key Points: Approximate analytical solutions for trapped electron distributions Reproduces simulations during quiet and storm times Could allow to infer average wave characteristics from measured distributions