Brillouin scattering during ionospheric beat wave heating: EISCAT observations and numerical modelling results

Description

Abstract C5.1-0003-21 (oral), id.821.
We report experimental observations of Brillouin scattering at EISCAT during ionospheric beat-wave heating. Observed nonlinear sidebands are attributed to nonlinear wave mixing in the ionosphere between the electromagnetic pump and probe waves. The results are supported by full-wave and ray-tracing simulations. When the large amplitude electromagnetic waves are injected vertically into the overhead plasma, the over-dense ionosphere works as a reflector, enabling resonant interaction between the reflected and up-going electromagnetic waves at altitudes where the difference frequency and wave vector of the probe and pump locally match those of the ion-acoustic (IA) wave. Extraordinary (X) mode waves are efficiently reflected at their cut-off, while ordinary (O) mode waves reach the critical layer where they are anomalously absorbed via conversion to electrostatic waves, heating the electrons. This leads to significant differences in the observed signals for O and X mode polarization.

Period	28 Jan 2021 → 4 Feb 2021
Event title	COSPAR Scientific Assembly 2020
Event type	Conference
Conference number	43rd
Location	Sydney, AustraliaShow on map
Degree of Recognition	International