F-region Drift Research Articles

Observation of movement of perturbations in the F-region

A summary is given of investigations into the phenomenon of travelling ionospheric disturbances in the F-region made at the Radio Research Laboratories, University of Sydney, Australia. The results of these investigations are compared with those made by other methods, and on a statistical basis measured speeds and directions do not agree. Possible explanations are given for this discrepancy. It is suggested that many general conclusions on F-region drift are drawn from selective data and that a whole range of different size perturbations exist in the ionospheric medium, the size and speed and direction of movement depending on the particular observational technique chosen. It is proposed that the Mitra method in particular is not entirely satisfactory for investigating F-region movement and should be supplemented by other techniques.

The correlation of radio-star-scintillation phenomena with geomagnetic disturbances and the mechanism of motion of the ionospheric irregularities in the F region

The paper describes an experimental investigation of the relation between the phenomena of scintillations of the radio stars and geomagnetic disturbances. A close correlation is found between the magnitude of the variations in the earth's magnetic field and F-region drift velocities as determined by the radio-star scintillation method. There is also occasional correlation between the amplitude of the scintillations and the magnetic variations. These results and those concerned with the reversals in drift directions are shown to be in agreement with the predictions of Martyn's theory, which ascribes the F-region phenomena to the interaction of the earth's magnetic field with an electric field communicated from the dynamo region.