OSCILLATION OF THE GEOMAGNETIC FIELD LINES AND ASSOCIATED MAGNETIC PERTURBATIONS AT CONJUGATE POINTS

By means of an idealized elastic string model, the symmetry relations in the magnetic perturbation at a pair of conjugate points due to oscillation of the lines of force of the geomagnetic field are studied. For oscillations of odd modes the change in H( DELTA H) is parallel, and that in the east c omponent ( DELTA D) is antiparallel, at the conjugate points, whereas for oscillations of even modes DELTA H is antiparallel and DELTA D is parallel at the conjugate points. Hence, in the former case the polarizations (as viewed downward) at the conjugate points are mirror images of each other with respect to the meridian plane, and in the latter case they are mirror images with respect to the equator. Several examples indicating these symmetry relations are presented. (auth) density had decreased in these regions of space as we moved away from the period of solar maximum. (auth)