The Polarization of Sky Waves in the Southern Hemisphere

Abstract

In the Southern Hemisphere, and for directions of propagation of downcoming waves very nearly parallel to the lines of force of the earth's magnetic field, the constants of polarization of sky waves deviated by the ionosphere at heights ranging between 94 and 262 kilometers have been measured. At all times the polarization was very nearly circular and right-handed. During the sunrise period, when measurements were thought to be liable to least error, the average value of the ratio of component alternating forces in the downcoming wave was found to be 1.4, the abnormally polarized component being greater than the normally polarized. The angular phase difference between the components was -84 degrees, the normal component leading the abnormal in time, and the sense of rotation of the resultant magnetic vector in the downcoming wave being clockwise. At other times, when the experimental conditions were not quite so suitable, due to the presence of multiple reflections and to phase and amplitude changes of the sky waves, the mean constants of polarization were 1.08 and -89.6 degrees, respectively, again showing circular right-handed polarization. The experimental conditions were carefully made similar to those of Appleton and Ratcliffe in England, these authors having found circular and left-handed polarization for directions of transmission along the lines of force of the earth's magnetic field. Their prediction that observations in the Southern Hemisphere for propagation against the lines of force of the earth's field should show circular polarization with a right-handed sense of rotation, has therefore been verified.