Conjugate three-dimensional polarization of high-latitude micropulsations from a hydromagnetic wave-ionospheric current model

The three-dimensional polarizations of high-latitude micropulsations of 30–300-second period are derived for conjugate point observatories from a simple rotating line current model that represents the actual ionospheric current system induced by circularly polarized standing hydromagnetic waves on the field lines. The sense of polarization in two vertical planes and the orientation of the polarization ellipses are shown to depend on the position of the observing station relative to the terminal point of the oscillating field line. Two classes of conjugate point relationships of the senses of polarization in the three orthogonal planes are derived from the model. The type of conjugate relationship is shown to depend on the mode of the standing transverse hydromagnetic wave. Polarization diagrams in the H-D, H-Z, and D-Z planes are constructed for Pc-4, Pc-5, and Pg-type micropulsations observed at Kiruna, Sweden, and at the College, Alaska-Macquarie Island conjugate pair to show the agreement of the polarization of high-latitude micropulsations with the predictions of the model.