Propagation of equatorial noise to low altitudes: decoupling from the magnetosonic mode - Archive ouverte HAL Access content directly
Journal Articles Geophysical Research Letters Year : 2016

Propagation of equatorial noise to low altitudes: decoupling from the magnetosonic mode

(1) , (2) , (1)
1
2

Abstract

Equatorial noise (often phenomenologically described as magnetosonic waves in the literature) is a natural electromagnetic emission which is generated by instability of ion distributions, and which can interact with electrons in the Van Allen radiation belts. We use multicomponent electromagnetic measurements of the DEMETER spacecraft to investigate if equatorial noise propagates inward down to the Earth. Analysis of a selected event recorded under disturbed geomagnetic conditions shows that equatorial noise can be observed at an altitude of 700 km, while propagating radially downward as a superposition of spectral lines from different distant sources observed at frequencies both below and above the local proton cyclotron frequency. Changes in the local ion composition encountered by the waves during their inward propagation disconnect the identified wave mode from the low frequency magnetosonic mode. The local ion composition also induces a cutoff which prevents the waves from propagating down to the ground.
Fichier principal
Vignette du fichier
Santol-k_et_al-2016-Geophysical_Research_Letters.pdf (3.28 Mo) Télécharger le fichier
Origin : Publisher files allowed on an open archive
Loading...

Dates and versions

insu-01340021 , version 1 (21-11-2016)

Identifiers

Cite

O. Santolík, Michel Parrot, F. Němec. Propagation of equatorial noise to low altitudes: decoupling from the magnetosonic mode. Geophysical Research Letters, 2016, 43, pp.6694-6704. ⟨10.1002/2016GL069582⟩. ⟨insu-01340021⟩
47 View
115 Download

Altmetric

Share

Gmail Facebook Twitter LinkedIn More