East Siberian Center for the Earth's Ionosphere Research (SDC ESCEIR)

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Incoherent scatter ionosphere diagnostics subdivision

Problems of the IS method theory, metric radiowave propagation and their non-linear interaction in the ionosphere

The radiophysical aspect of the application of the IS method is of interest to ISTP researchers . This interest applies not only the improvement of the measurement quality (space and time resolution), but also for additional problems which can be solved with the Irkutsk radar.

A most promising problem is to investigate the interaction of two VHF powerful radiowave beams in the ionosphere, whose difference frequency is equal to the plasma frequency in some ionospheric area (that is, the difference frequency is taken in the range 1-8 MHz). This problem lies at the junction of radiophysics, ionosphere physics, and plasma physics. Two-frequency interaction effects are based on radiowave non-linear mixing, which is rather complicated when describing and modelling the experiment. The possible generation of ionospheric irregularities gives rise to the questions of their development and propagation from the area of generation. Besides the questions of experiment technical realization, the issues of the physical mechanisms of such interactions in real magnetized plasma still remain open.

Another problem is investigating of IS signal realizations the fine structure, which is thought of as being a stochastic process, hence we must process this signal by a statistical method on the signal parameter field (power, energy spectrum,correlation function). It is correct if the signal/noise ratio is experimentally small. However, if the signal is ten times larger than noise, interest in the signal structure and properties is quite reasonable.

Of great interest are powerful coherent echoes which erise during strong geomagnetic disturbances. Their structure still remains poorly understoos and hence is the subject of scientific research.