Excitation of strong Langmuir turbulence in the ionosphere: Comparison of theory and observations*

The predictions of models of strong Langmuir turbulence (SLT) are compared with recent space- and time-resolved radar observations of the power spectra of turbulence induced in the ionosphere by powerful high-frequency (HF) waves. Distinct signatures of caviton dynamics, not predicted by the weak turbulence approximation, are seen in the observations. An improved model of the low-frequency fluctuations for equal electron and ion temperatures is presented as well as a discussion of density profile modification by the induced turbulence.