Toward some new directions in Pc5 pulsation theory—I. Consequences of ionosphere hall current

The Pc5 pulsation model of Rostoker and Lam (1978), which was constructed on the assumption of a non-axisymmetric magnetosphere-ionosphere, is extended to account for the consequence of the ionosphere Hall current. The purpose of the extension is to determine if the more difficult equivalent extension of the hydromagnetic wave theory would be profitable by obtaining some insight into the probable results of such an extension. The new model predicts that the natural resonant frequency is altered by the ionosphere conductivities. This alteration is examined in detail. Another prediction is that the east-west current flow in the ionosphere differs in phase from the north-south current. This phase difference contributes to the polarization properties of the ground-observed pulsations. These results are consequences of the behaviour of the resonant circuit and not that of the signal source. The relationship of this work to that using the traditional approach is discussed.