Abstrakt
In this study, we use the observations of electromagnetic waves by Detection of Electromagnetic Emissions Transmitted from Earthquake Regions satellite to investigate propagation characteristics of low-altitude ionospheric hiss. In an event study, intense hiss wave power is concentrated over a narrow frequency band with a central frequency that decreases as latitude decreases, which coincides to the variation of local proton cyclotron frequency f(CH).
The wave propagates obliquely to the background magnetic field and equatorward from high latitude region. We use about similar to 6 years of observations to statistically study the dependence of ionospheric hiss wave power on location, local time, geomagnetic activity, and season.
The results demonstrate that the ionospheric hiss power is stronger on the dayside than nightside, under higher geomagnetic activity conditions, in local summer than local winter. The wave power is confined near the region where the local fCH is equal to the wave frequency.
A ray tracing simulation is performed to account for the dependence of wave power on frequency and latitude.