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Observational evidence of electron pitch angle scattering driven by ECH waves
Author(s) -
Kurita Satoshi,
Miyoshi Yoshizumi,
Cully Christopher M.,
Angelopoulos Vassilis,
Contel Olivier Le,
Hikishima Mitsuru,
Misawa Hiroaki
Publication year - 2014
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2014gl061927
Subject(s) - physics , scattering , pitch angle , whistler , computational physics , electron , diffusion , atomic physics , optics , geophysics , nuclear physics , thermodynamics
Using the plasma wave and electron data obtained from Time History of Events and Macroscale Interactions during Substorms, we show a signature of electron pitch angle scattering driven by Electrostatic Cyclotron Harmonic (ECH) waves in the velocity distribution function (VDF). The diffusion curve of whistler mode waves is used as a proxy to identify changes in VDFs due to wave‐particle interactions. We confirm that the shape of the VDF well agrees with the diffusion curve of whistler mode waves when whistler mode chorus alone is active. On the other hand, we find that the shape of the VDF deviates from the diffusion curves at low pitch angles when ECH waves are active following the inactivation of chorus waves. The result is observational support for electron pitch angle scattering caused by ECH waves and suggests that ECH waves can contribute to generation of diffuse auroras.