Laboratory modeling of ionospheric heating experiments

Turbulent plasma processes, such as those which occur in the Earth's ionosphere during ionospheric heating by powerful radio waves, were studied under laboratory conditions, and new physical models of small‐scale ionospheric turbulence are proposed as a result of these studies. It is shown here that the mechanism of small‐scale plasma filamentation can be connected with the thermal self‐channeling of Langmuir waves. During this process, Langmuir waves are guided by a plasma channel, which in turn is formed by the guided waves through a thermal plasma nonlinearity. The spectrum of the self‐guided Langmuir waves exhibits sidebands whose features are similar to stimulated electromagnetic emission. We present two mechanisms of sideband generation. The first mechanism can be observed during the formation of the plasma channel and is connected with the parametric shift in the frequency of the self‐channeling wave. The second mechanism is connected with the scattering of the self‐channeling wave on the low‐frequency eigenmodes of the plasma irregularity. Key Points Thermal self‐channeling of Langmuir waves is the main mechanism of small‐scale plasma filamentation The spectrum of the self‐guided Langmuir waves exhibits spectral satellites similar to SEE features The satellites are generated due to the parametric effects and due to the guided wave scattering