Rocket observation of topside resonances

In a recent rocket experiment designed to resolve the slow-wave echoes comprising the resonances excited by topside sounders the plasma, the upper hybrid resonance, and the first three electron cyclotron resonances were observed. In particular, the variation of echo frequency versus delay was observed for the upper hybrid resonance. The good agreement found between the observed and the predicted frequency delay function confirms the slow-wave propagation nature of the phenomenon. The frequency of all three electron cyclotron resonances are consistent with the Pogo (3/68) magnetic-field model within its stated accuracy.