A TEST FOR DISPERSION IN F-REGION DRIFTS OBSERVED BY RADIO STAR SCINTILLATION METHOD

Records of scintillations of the source Cassiopeia A made on 38 Mc/s using three spaced interferometers have been analysed to determine whether Fourier components of different frequencies give different values of drift velocity. Such an effect is found to occur, and in most cases the speed of drift increases with frequency, while the direction of drift does not change. This effect is related to a systematic 'skewness' of the cross-correlation functions. The dispersion could be produced by the propagation of some type of dispersive wave through the F-region of the ionosphere, but it is considered more likely that it is produced by a variation of drift velocity along the line of sight. © 1968.