Source of the low-altitude hiss in the ionosphere

Lunjin Chen (1) , Ondřej Santolík (2) , Mychajlo Hajoš (2) , Liheng Zheng (1) , Zeren Zhima (1) , Roderick Heelis (1) , Miroslav Hanzelka (2) , Richard B. Horne (3) , Michel Parrot (4)

1 William B. Hanson Center for Space Sciences
2 Faculty of Mathematics and Physics [Praha/Prague]
3 BAS - British Antarctic Survey
4 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace

We analyze the propagation properties of low-altitude hiss emission in the ionosphere observed by DEMETER (Detection of Electromagnetic Emissions Transmitted from Earthquake Regions). There exist two types of low-altitude hiss: type I emission at high latitude is characterized by vertically downward propagation and broadband spectra, while type II emission at low latitude is featured with equatorward propagation and a narrower frequency band above ∼f cH+. Our ray tracing simulation demonstrates that both types of the low-altitude hiss at different latitude are connected and they originate from plasmaspheric hiss and in part chorus emission. Type I emission represents magnetospheric whistler emission that accesses the ionosphere. Equatorward propagation associated with type II emission is a consequence of wave trapping mechanisms in the ionosphere. Two different wave trapping mechanisms are identified to explain the equatorial propagation of Type II emission; one is associated with the proximity of wave frequency and local proton cyclotron frequency, while the other occurs near the ionospheric density peak.

Domains: Sciences of the Universe [physics]; Earth Sciences; Geophysics [physics.geo-ph]; Physics [physics]; Physics [physics]; Space Physics [physics.space-ph]

Lunjin Chen, Ondřej Santolík, Mychajlo Hajoš, Liheng Zheng, Zeren Zhima, et al.. Source of the low-altitude hiss in the ionosphere. Geophysical Research Letters, 2017, 44 (5), pp.2060-2069. ⟨10.1002/2016GL072181⟩. ⟨insu-01503086⟩