Hemispheric Effects in Ionospheric Plasma Convection and Irregularity Occurrence

Abstract:

Extensive statistical studies have demonstrated the extent of asymmetries between the hemispheres in terms of the global pattern of plasma convection in the high-latitude ionosphere. However, relatively little is known about the asymmetries that arise on meso and smaller spatial scales or in the course of reconfiguration of the global convection following changes in IMF or substorm onsets. Moreover the correspondence between the hemispheres in space weather effects such as the occurrence of ionospheric plasma irregularities is almost unexplored. Some of the challenges in conducting such studies are traceable to more limited observational capabilities in the southern hemisphere. New capabilities have recently been achieved with the expansion of the SuperDARN radar network such that simultaneous and quasi-conjugate coverage is sometimes possible from midlatitudes to the polar cap. We review findings on the asymmetric aspects of high-latitude convection and press further to consider evidence of correspondence and asymmetry in convection when varying in time and across the equatorward auroral and midlatitude regions where conjugacy should obtain more reliably. We also discuss evidence of correlation between the hemispheres in terms of the occurrence of small-scale irregularities as a space weather phenomenon of practical importance.