Strange Currents Over Saint-Santin

Analysis of 29 days of ionospheric current data obtained by Saint-Santin radar, including both magnetically quiet and disturbed periods, has confirmed the existence of northward currents at all daytime hours. The postulate of field-aligned Van Sabben currents driven by interhemispherical asymmetries seems to be able to account for the anomaly. The desirability of quantitative modeling of the Van Sabben currents on a seasonal or day-to-day basis is highlighted by the Saint-Santin measurements.