Conjugate and closely-spaced observations of auroral radio absorption—V: Alternation of auroral particle precipitation between hemispheres

Abstract

Short-term differences of auroral radio absorption in conjugate regions are investigated by means of specific absorption events observed with spaced riometer systems at Great Whale River and Byrd. It is demonstrated that some of the observed conjugate differences cannot be explained by displacement of the conjugate point, and probably arise from an inter-hemispheric difference of particle precipitation in which the flux of auroral particles in enhanced alternately in the northern and southern hemispheres. The phenomenon occurs mainly in the night sector, and the alternation periods are tens of minutes to an hour or two. The observations may be indicative of the behaviour of magnetospheric electric fields aligned parallel to the geomagnetic field.