Effects of long-lasting interplanetary magnetic field perturbations on the equatorial ionosphere

Abstract

During 3 -7 July, 2003, long-lasting and large-amplitude interplanetary magnetic field perturbation event occurred. This event is classified as high-intensity long-duration continuous AE activity (HILDCAA) which occurs outside the main phase of magnetic storms. The responses of the equatorial ionosphere to HILDCAA events have been poorly known so far. In this work, we investigate the effects of HILDCAA events on the equatorial ionosphere using ionosonde data (hmF2) observed at São Luís, Brazil and the ACE satellite data. The results indicate presence of short-time prompt penetration electric field disturbances and long-lived positive charge accumulation at the magnetic equator around the midnight sector due to the disturbance dynamo effect.