Relationships between auroral and concurrent geomagnetic pulsations

Studies of the relationships between auroral and concurrent geomagnetic pulsations, PiC, in the auroral zone are reviewed with emphasis on the most recent developments. Processes are described which lead to the conclusion that the magnetic pulsations are caused by temporal and spatial fluctuations of electric currents induced in enhancements of the ionospheric electric conductivity produced by pulsating precipitation of auroral electrons. It is further concluded that the currents also account for magnetic fluctuations measured by MAGSAT above a pulsating aurora as well as PiC pulsations observed on the ground at the same time. The relationships between auroral and concurrent magnetic pulsations have now been firmly established, not only for the magnetic pulsations on the ground but also for those observed by a low altitude satellite above the ionosphere.