Theory of short‐scale field‐aligned density striations due to ionospheric heating

The theoretical saturation spectrum of parametrically excited Langmuir waves in a locally uniform ionosphere is shown by the present claculations to produce, by ohmic dissipation, short‐scale field‐aligned density striations. The spectrum of the calculated striations is not inconsistent with observations of field‐aligned scatter of VHF and UHF waves in ionospheric modification experiments if local increases of the pump field due to focusing are invoked.