DescriptionIonospheric beat- wave Brillouin scattering experiment: Observation and Numerical Simulations
We report experimental observations of Brillouin scattering at EISCAT in Northern Norway 29 November 2014 during ionospheric beat-wave heating using a large amplitude electromagnetic (EM) pump wave combined with a weaker probe wave that was stepped down in frequency below that of the pump wave. When the large amplitude EM waves are injected vertically into the overhead plasma, the over-dense ionosphere works as a reflector, enabling resonant interaction between the down-going and up-going EM waves at altitudes where the difference frequency and wave vector of the probe and pump locally match those of the ion-acoustic (IA) wave. The results are supported by full-wave and ray-tracing simulations. Observed frequency sidebands are attributed to nonlinear wave mixing in the ionosphere between the EM pump and probe waves. Extraordinary (X) mode waves are efficiently reflected at their cut-off, while ordinary (O) mode waves reach the upper hybrid and critical layers 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||19 May 2021|
|Event title||International e-Conference on Recent Trends in Plasma Physics|
- ionospheric turbulence
- Brillouin scattering
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